first commit

Semester 1/Programming 1/Java/examples/projects/chapter16/taxi-company-later-stage/Actor.ctxt

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+#BlueJ class context
+comment0.params=
+comment0.target=void\ act()
+comment0.text=\n\ Implement\ the\ actor's\ behavior.\n
+numComments=1

Semester 1/Programming 1/Java/examples/projects/chapter16/taxi-company-later-stage/Actor.java

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+/**
+ * An actor in the taxi-company simulation.
+ * 
+ * @author David J. Barnes and Michael Kölling
+ * @version 2016.02.29
+ */
+public interface Actor
+{
+    /**
+     * Implement the actor's behavior.
+     */
+    public void act();
+}

Semester 1/Programming 1/Java/examples/projects/chapter16/taxi-company-later-stage/City.ctxt

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+#BlueJ class context
+comment0.params=width\ height
+comment0.target=City(int,\ int)
+comment0.text=\n\ Constructor\ for\ objects\ of\ class\ City\n\ @param\ width\ The\ city's\ width.\n\ @param\ height\ The\ city's\ height.\n
+comment1.params=
+comment1.target=City()
+comment1.text=\n\ Create\ a\ city\ of\ default\ size.\n
+comment2.params=
+comment2.target=java.util.Iterator\ getItems()
+comment2.text=\n\ @return\ An\ iterator\ over\ the\ items.\n
+comment3.params=item
+comment3.target=void\ addItem(Item)
+comment3.text=\n\ Add\ the\ given\ item\ to\ the\ city's\ collection.\n\ @param\ item\ The\ item\ to\ be\ added.\n
+comment4.params=item
+comment4.target=void\ removeItem(Item)
+comment4.text=\n\ Remove\ the\ given\ item\ from\ the\ city's\ collection.\n\ @param\ item\ The\ item\ to\ be\ removed.\n
+comment5.params=
+comment5.target=java.lang.String\ toString()
+comment5.text=\n\ @return\ A\ string\ representation\ of\ the\ city.\n
+comment6.params=
+comment6.target=int\ getWidth()
+comment6.text=\n\ @return\ The\ width.\n
+comment7.params=
+comment7.target=int\ getHeight()
+comment7.text=\n\ @return\ The\ height.\n
+numComments=8

Semester 1/Programming 1/Java/examples/projects/chapter16/taxi-company-later-stage/City.java

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+import java.util.Iterator;
+import java.util.LinkedList;
+import java.util.List;
+    
+/**
+ * A collection of items in the city.
+ * 
+ * @author David J. Barnes and Michael Kölling
+ * @version 2016.02.29
+ */
+public class City
+{
+    private List<Item> items;
+    private int width;
+    private int height;
+    
+    private static final int DEFAULT_WIDTH = 35;
+    private static final int DEFAULT_HEIGHT = 35;
+
+    /**
+     * Constructor for objects of class City
+     * @param width The city's width.
+     * @param height The city's height.
+     */
+    public City(int width, int height)
+    {
+        if(width < 1) {
+            throw new IllegalArgumentException(
+                        "Width must be positive: " +
+                        width);
+        }
+        if(height < 1) {
+            throw new IllegalArgumentException(
+                        "Height must be positive: " +
+                        height);
+        }
+        this.width = width;
+        this.height = height;
+        items = new LinkedList<>();
+    }
+    
+    /**
+     * Create a city of default size.
+     */
+    public City()
+    {
+        this(DEFAULT_WIDTH, DEFAULT_HEIGHT);
+    }
+    
+    /**
+     * @return An iterator over the items.
+     */
+    public Iterator<Item> getItems()
+    {
+        return items.iterator();
+    }
+
+    /**
+     * Add the given item to the city's collection.
+     * @param item The item to be added.
+     */
+    public void addItem(Item item)
+    {
+        if(items.contains(item)) {
+            throw new IllegalArgumentException(
+                item + " already recorded in the city.");
+        }
+        items.add(item);
+    }
+
+    /**
+     * Remove the given item from the city's collection.
+     * @param item The item to be removed.
+     */
+    public void removeItem(Item item)
+    {
+        if(!items.remove(item)) {
+            throw new IllegalArgumentException(
+                        item + " is not in the city.");
+        }
+    }
+        
+    /**
+     * @return A string representation of the city.
+     */
+    public String toString()
+    {
+        return "City size " + width + " by " + height;
+    }
+    
+    /**
+     * @return The width.
+     */
+    public int getWidth()
+    {
+        return width;
+    }
+    
+    /**
+     * @return The height.
+     */
+    public int getHeight()
+    {
+        return height;
+    }
+}

Semester 1/Programming 1/Java/examples/projects/chapter16/taxi-company-later-stage/CityGUI.ctxt

@@ -0,0 +1,8 @@
+#BlueJ class context
+comment0.params=city
+comment0.target=CityGUI(City)
+comment0.text=\n\ Constructor\ for\ objects\ of\ class\ CityGUI\n\ @param\ city\ The\ city\ whose\ state\ is\ to\ be\ displayed.\n
+comment1.params=
+comment1.target=void\ act()
+comment1.text=\n\ Display\ the\ current\ state\ of\ the\ city.\n
+numComments=2

Semester 1/Programming 1/Java/examples/projects/chapter16/taxi-company-later-stage/CityGUI.java

@@ -0,0 +1,151 @@
+import java.util.HashMap;
+import java.util.Iterator;
+import java.util.Map;
+import java.awt.*;
+import javax.swing.*;
+    
+/**
+ * Provide a view of the vehicles and passengers in the city.
+ * 
+ * @author David J. Barnes and Michael Kölling
+ * @version 2016.02.29
+ */
+public class CityGUI extends JFrame implements Actor
+{
+    // The dimensions of the GUI.
+    public static final int CITY_VIEW_WIDTH = 600;
+    public static final int CITY_VIEW_HEIGHT = 600;
+    private City city;
+    private CityView cityView;
+    
+    /**
+     * Constructor for objects of class CityGUI
+     * @param city The city whose state is to be displayed.
+     */
+    public CityGUI(City city)
+    {
+        this.city = city;
+        cityView = new CityView(city.getWidth(), city.getHeight());
+        getContentPane().add(cityView);
+        setTitle("Taxiville");
+        setSize(CITY_VIEW_WIDTH, CITY_VIEW_HEIGHT);
+        setVisible(true);
+        cityView.preparePaint();
+        cityView.repaint();    
+    }
+    
+    /**
+     * Display the current state of the city.
+     */
+    public void act()
+    {
+        cityView.preparePaint();
+        Iterator<Item> items = city.getItems();
+        while(items.hasNext()) {
+            Item item = items.next();
+            if(item instanceof DrawableItem){
+                DrawableItem drawable = (DrawableItem) item;
+                Location location = item.getLocation();
+                cityView.drawImage(location.getX(), location.getY(), drawable.getImage());
+            }
+        }
+        cityView.repaint();    
+    }
+    
+    /**
+     * Provide a graphical view of a rectangular city. This is 
+     * a nested class (a class defined inside a class) which
+     * defines a custom component for the user interface. This
+     * component displays the city.
+     * This is rather advanced GUI stuff - you can ignore this 
+     * for your project if you like.
+     */
+    private class CityView extends JPanel
+    {
+        private final int VIEW_SCALING_FACTOR = 6;
+
+        private int cityWidth, cityHeight;
+        private int xScale, yScale;
+        private Dimension size;
+        private Graphics g;
+        private Image cityImage;
+
+        /**
+         * Create a new CityView component.
+         */
+        public CityView(int width, int height)
+        {
+            cityWidth = width;
+            cityHeight = height;
+            setBackground(Color.white);
+            size = new Dimension(0, 0);
+        }
+
+        /**
+         * Tell the GUI manager how big we would like to be.
+         */
+        public Dimension getPreferredSize()
+        {
+            return new Dimension(cityWidth * VIEW_SCALING_FACTOR,
+                                 cityHeight * VIEW_SCALING_FACTOR);
+        }
+        
+        /**
+         * Prepare for a new round of painting. Since the component
+         * may be resized, compute the scaling factor again.
+         */
+        public void preparePaint()
+        {
+            if(!size.equals(getSize())) {  // if the size has changed...
+                size = getSize();
+                cityImage = cityView.createImage(size.width, size.height);
+                g = cityImage.getGraphics();
+
+                xScale = size.width / cityWidth;
+                if(xScale < 1) {
+                    xScale = VIEW_SCALING_FACTOR;
+                }
+                yScale = size.height / cityHeight;
+                if(yScale < 1) {
+                    yScale = VIEW_SCALING_FACTOR;
+                }
+            }
+            g.setColor(Color.white);
+            g.fillRect(0, 0, size.width, size.height);
+            g.setColor(Color.gray);
+            for(int i = 0, x = 0; x < size.width; i++, x = i * xScale) {
+                g.drawLine(x, 0, x, size.height - 1);
+            }
+            for(int i = 0, y = 0; y < size.height; i++, y = i * yScale) {
+                g.drawLine(0, y, size.width - 1, y);
+            }
+        }
+        
+        /**
+         * Draw the image for a particular item.
+         */
+        public void drawImage(int x, int y, Image image)
+        {
+            g.drawImage(image, x * xScale + 1, y * yScale + 1,
+                        xScale - 1, yScale - 1, this);
+        }
+
+        /**
+         * The city view component needs to be redisplayed. Copy the
+         * internal image to screen.
+         */
+        public void paintComponent(Graphics g)
+        {
+            if(cityImage != null) {
+                Dimension currentSize = getSize();
+                if(size.equals(currentSize)) {
+                    g.drawImage(cityImage, 0, 0, null);
+                }
+                else {
+                    // Rescale the previous image.
+                    g.drawImage(cityImage, 0, 0, currentSize.width, currentSize.height, null);
+                }
+            }
+        }
+    }
+}

Semester 1/Programming 1/Java/examples/projects/chapter16/taxi-company-later-stage/DrawableItem.ctxt

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+#BlueJ class context
+comment0.params=
+comment0.target=java.awt.Image\ getImage()
+numComments=1

Semester 1/Programming 1/Java/examples/projects/chapter16/taxi-company-later-stage/DrawableItem.java

@@ -0,0 +1,13 @@
+import java.awt.Image;
+    
+/**
+ * An item that is able to return an image of itself.
+ * 
+ * @author David J. Barnes and Michael Kölling
+ * @version 2016.02.29
+ */
+
+public interface DrawableItem extends Item
+{
+    public Image getImage();
+}

Semester 1/Programming 1/Java/examples/projects/chapter16/taxi-company-later-stage/Item.ctxt

@@ -0,0 +1,4 @@
+#BlueJ class context
+comment0.params=
+comment0.target=Location\ getLocation()
+numComments=1

Semester 1/Programming 1/Java/examples/projects/chapter16/taxi-company-later-stage/Item.java

@@ -0,0 +1,11 @@
+/**
+ * An item in the city.
+ * 
+ * @author David J. Barnes and Michael Kölling
+ * @version 2016.02.29
+ */
+
+public interface Item
+{
+    public Location getLocation();
+}

Semester 1/Programming 1/Java/examples/projects/chapter16/taxi-company-later-stage/Location.ctxt

@@ -0,0 +1,26 @@
+#BlueJ class context
+comment0.params=x\ y
+comment0.target=Location(int,\ int)
+comment0.text=\n\ Model\ a\ location\ in\ the\ city.\n\ @param\ x\ The\ x\ coordinate.\ Must\ be\ positive.\n\ @param\ y\ The\ y\ coordinate.\ Must\ be\ positive.\n\ @throws\ IllegalArgumentException\ If\ a\ coordinate\ is\ negative.\n
+comment1.params=destination
+comment1.target=Location\ nextLocation(Location)
+comment1.text=\n\ Generate\ the\ next\ location\ to\ visit\ in\ order\ to\n\ reach\ the\ destination.\n\ @param\ destination\ Where\ we\ want\ to\ get\ to.\n\ @return\ A\ location\ in\ a\ direct\ line\ from\ this\ to\n\ \ \ \ \ \ \ \ \ destination.\n
+comment2.params=destination
+comment2.target=int\ distance(Location)
+comment2.text=\n\ Determine\ the\ number\ of\ movements\ required\ to\ get\n\ from\ here\ to\ the\ destination.\n\ @param\ destination\ The\ required\ destination.\n\ @return\ The\ number\ of\ movement\ steps.\n
+comment3.params=other
+comment3.target=boolean\ equals(java.lang.Object)
+comment3.text=\n\ Implement\ content\ equality\ for\ locations.\n\ @return\ true\ if\ this\ location\ matches\ the\ other,\n\ \ \ \ \ \ \ \ \ false\ otherwise.\n
+comment4.params=
+comment4.target=java.lang.String\ toString()
+comment4.text=\n\ @return\ A\ representation\ of\ the\ location.\n
+comment5.params=
+comment5.target=int\ hashCode()
+comment5.text=\n\ Use\ the\ top\ 16\ bits\ for\ the\ y\ value\ and\ the\ bottom\ for\ the\ x.\n\ Except\ for\ very\ big\ grids,\ this\ should\ give\ a\ unique\ hash\ code\n\ for\ each\ (x,\ y)\ pair.\n\ @return\ A\ hashcode\ for\ the\ location.\n
+comment6.params=
+comment6.target=int\ getX()
+comment6.text=\n\ @return\ The\ x\ coordinate.\n
+comment7.params=
+comment7.target=int\ getY()
+comment7.text=\n\ @return\ The\ y\ coordinate.\n
+numComments=8

Semester 1/Programming 1/Java/examples/projects/chapter16/taxi-company-later-stage/Location.java

@@ -0,0 +1,117 @@
+/**
+ * Model a location in a city.
+ * 
+ * @author David J. Barnes and Michael Kölling
+ * @version 2016.02.29
+ */
+public class Location
+{
+    private int x;
+    private int y;
+
+    /**
+     * Model a location in the city.
+     * @param x The x coordinate. Must be positive.
+     * @param y The y coordinate. Must be positive.
+     * @throws IllegalArgumentException If a coordinate is negative.
+     */
+    public Location(int x, int y)
+    {
+        if(x < 0) {
+            throw new IllegalArgumentException(
+                        "Negative x-coordinate: " + x);
+        }
+        if(y < 0) {
+            throw new IllegalArgumentException(
+                        "Negative y-coordinate: " + y);
+        }
+        this.x = x;
+        this.y = y;
+    }
+    
+    /**
+     * Generate the next location to visit in order to
+     * reach the destination.
+     * @param destination Where we want to get to.
+     * @return A location in a direct line from this to
+     *         destination.
+     */
+    public Location nextLocation(Location destination)
+    {
+        int destX = destination.getX();
+        int destY = destination.getY();
+        int offsetX = x < destX ? 1 : x > destX ? -1 : 0;
+        int offsetY = y < destY ? 1 : y > destY ? -1 : 0;
+        if(offsetX != 0 || offsetY != 0) {
+            return new Location(x + offsetX, y + offsetY);
+        }
+        else {
+            return destination;
+        }
+    }
+
+    /**
+     * Determine the number of movements required to get
+     * from here to the destination.
+     * @param destination The required destination.
+     * @return The number of movement steps.
+     */
+    public int distance(Location destination)
+    {
+        int xDist = Math.abs(destination.getX() - x);
+        int yDist = Math.abs(destination.getY() - y);
+        return Math.max(xDist, yDist);
+    }
+    
+    /**
+     * Implement content equality for locations.
+     * @return true if this location matches the other,
+     *         false otherwise.
+     */
+    public boolean equals(Object other)
+    {
+        if(other instanceof Location) {
+            Location otherLocation = (Location) other;
+            return x == otherLocation.getX() &&
+                   y == otherLocation.getY();
+        }
+        else {
+            return false;
+        }
+    }
+    
+    /**
+     * @return A representation of the location.
+     */
+    public String toString()
+    {
+        return "location " + x + "," + y;
+    }
+
+    /**
+     * Use the top 16 bits for the y value and the bottom for the x.
+     * Except for very big grids, this should give a unique hash code
+     * for each (x, y) pair.
+     * @return A hashcode for the location.
+     */
+    public int hashCode()
+    {
+        return (y << 16) + x;
+    }
+
+    /**
+     * @return The x coordinate.
+     */
+    public int getX()
+    {
+        return x;
+    }
+
+    /**
+     * @return The y coordinate.
+     */
+    public int getY()
+    {
+        return y;
+    }
+}

Semester 1/Programming 1/Java/examples/projects/chapter16/taxi-company-later-stage/MissingPassengerException.ctxt

@@ -0,0 +1,8 @@
+#BlueJ class context
+comment0.params=vehicle
+comment0.target=MissingPassengerException(Vehicle)
+comment0.text=\n\ Constructor\ for\ objects\ of\ class\ MissingPassengerException.\n\ @param\ vehicle\ The\ vehicle\ expecting\ a\ passenger.\n
+comment1.params=
+comment1.target=Vehicle\ getVehicle()
+comment1.text=\n\ @return\ The\ vehicle\ for\ which\ there\ was\ no\ passenger.\n
+numComments=2

Semester 1/Programming 1/Java/examples/projects/chapter16/taxi-company-later-stage/MissingPassengerException.java

@@ -0,0 +1,27 @@
+
+/**
+ * Indicate that there was no passenger at a pickup point.
+ * 
+ * @author David J. Barnes and Michael Kölling
+ * @version 2016.02.29
+ */
+public class MissingPassengerException extends RuntimeException
+{
+    private Vehicle vehicle;
+    /**
+     * Constructor for objects of class MissingPassengerException.
+     * @param vehicle The vehicle expecting a passenger.
+     */
+    public MissingPassengerException(Vehicle vehicle)
+    {
+        super("Missing passenger at pickup location.");
+    }
+
+    /**
+     * @return The vehicle for which there was no passenger.
+     */
+    public Vehicle getVehicle()
+    {
+        return vehicle;
+    }
+}

Semester 1/Programming 1/Java/examples/projects/chapter16/taxi-company-later-stage/Passenger.ctxt

@@ -0,0 +1,20 @@
+#BlueJ class context
+comment0.params=pickup\ destination
+comment0.target=Passenger(Location,\ Location)
+comment0.text=\n\ Constructor\ for\ objects\ of\ class\ Passenger\n\ @param\ pickup\ The\ pickup\ location,\ must\ not\ be\ null.\n\ @param\ destination\ The\ destination\ location,\ must\ not\ be\ null.\n\ @throws\ NullPointerException\ If\ either\ location\ is\ null.\n
+comment1.params=
+comment1.target=java.lang.String\ toString()
+comment1.text=\n\ @return\ A\ string\ representation\ of\ this\ person.\n
+comment2.params=
+comment2.target=java.awt.Image\ getImage()
+comment2.text=\n\ @return\ The\ image\ to\ be\ displayed\ on\ a\ GUI.\n
+comment3.params=
+comment3.target=Location\ getLocation()
+comment3.text=\n\ @return\ The\ passenger's\ pickup\ location.\n
+comment4.params=
+comment4.target=Location\ getPickupLocation()
+comment4.text=\n\ @return\ The\ pickup\ location.\n
+comment5.params=
+comment5.target=Location\ getDestination()
+comment5.text=\n\ @return\ The\ destination\ location.\n
+numComments=6

Semester 1/Programming 1/Java/examples/projects/chapter16/taxi-company-later-stage/Passenger.java

@@ -0,0 +1,78 @@
+import java.awt.Image;
+import javax.swing.ImageIcon;
+
+/**
+ * Model a passenger wishing to get from one
+ * location to another.
+ * 
+ * @author David J. Barnes and Michael Kölling
+ * @version 2016.02.29
+ */
+public class Passenger implements DrawableItem
+{
+    private Location pickup;
+    private Location destination;
+    private Image image;
+
+    /**
+     * Constructor for objects of class Passenger
+     * @param pickup The pickup location, must not be null.
+     * @param destination The destination location, must not be null.
+     * @throws NullPointerException If either location is null.
+     */
+    public Passenger(Location pickup, Location destination)
+    {
+        if(pickup == null) {
+            throw new NullPointerException("Pickup location");
+        }
+        if(destination == null) {
+            throw new NullPointerException("Destination location");
+        }
+        this.pickup = pickup;
+        this.destination = destination;
+        // Load the image used to represent a person.
+        image = new ImageIcon(getClass().getResource(
+                              "images/person.jpg")).getImage();
+    }
+    
+    /**
+     * @return A string representation of this person.
+     */
+    public String toString()
+    {
+        return "Passenger travelling from " +
+               pickup + " to " + destination;
+    }
+
+    /**
+     * @return The image to be displayed on a GUI.
+     */
+    public Image getImage()
+    {
+        return image;
+    }
+    
+    /**
+     * @return The passenger's pickup location.
+     */
+    public Location getLocation()
+    {
+        return pickup;
+    }
+
+    /**
+     * @return The pickup location.
+     */
+    public Location getPickupLocation()
+    {
+        return pickup;
+    }
+    
+    /**
+     * @return The destination location.
+     */
+    public Location getDestination()
+    {
+        return destination;
+    }
+}

Semester 1/Programming 1/Java/examples/projects/chapter16/taxi-company-later-stage/PassengerSource.ctxt

@@ -0,0 +1,14 @@
+#BlueJ class context
+comment0.params=city\ company
+comment0.target=PassengerSource(City,\ TaxiCompany)
+comment0.text=\n\ Constructor\ for\ objects\ of\ class\ PassengerSource.\n\ @param\ city\ The\ city.\ Must\ not\ be\ null.\n\ @param\ company\ The\ company\ to\ be\ used.\ Must\ not\ be\ null.\n\ @throws\ NullPointerException\ if\ city\ or\ company\ is\ null.\n
+comment1.params=
+comment1.target=void\ act()
+comment1.text=\n\ Randomly\ generate\ a\ new\ passenger.\n\ Keep\ a\ count\ of\ missed\ pickups.\n
+comment2.params=
+comment2.target=int\ getMissedPickups()
+comment2.text=\n\ @return\ The\ number\ of\ passengers\ for\ whom\ a\ pickup\n\ \ \ \ \ \ \ \ \ could\ not\ be\ found.\n
+comment3.params=
+comment3.target=Passenger\ createPassenger()
+comment3.text=\n\ Create\ a\ new\ passenger\ with\ distinct\ pickup\ and\n\ destination\ locations.\n\ @return\ The\ created\ passenger.\n
+numComments=4

Semester 1/Programming 1/Java/examples/projects/chapter16/taxi-company-later-stage/PassengerSource.java

@@ -0,0 +1,91 @@
+import java.util.Iterator;
+import java.util.LinkedList;
+import java.util.List;
+import java.util.Random;
+
+/**
+ * Periodically generate passengers.
+ * Keep track of the number of passengers for whom
+ * a vehicle cannot be found.
+ * 
+ * @author David J. Barnes and Michael Kölling
+ * @version 2016.02.29
+ */
+public class PassengerSource implements Actor
+{
+    private City city;
+    private TaxiCompany company;
+    private Random rand;
+    private static final double CREATION_PROBABILITY = 0.06;
+    private int missedPickups;
+
+    /**
+     * Constructor for objects of class PassengerSource.
+     * @param city The city. Must not be null.
+     * @param company The company to be used. Must not be null.
+     * @throws NullPointerException if city or company is null.
+     */
+    public PassengerSource(City city, TaxiCompany company)
+    {
+        if(city == null) {
+            throw new NullPointerException("city");
+        }
+        if(company == null) {
+            throw new NullPointerException("company");
+        }
+        this.city = city;
+        this.company = company;
+        // Use a fixed random seed for repeatable effects.
+        // Change this to produce more random effects.
+        rand = new Random(12345);
+        missedPickups = 0;
+    }
+
+    /**
+     * Randomly generate a new passenger.
+     * Keep a count of missed pickups.
+     */
+    public void act()
+    {
+        if(rand.nextDouble() <= CREATION_PROBABILITY) {
+            Passenger passenger = createPassenger();
+            if(company.requestPickup(passenger)) {
+                city.addItem(passenger);
+            }
+            else {
+                missedPickups++;
+            }
+        }
+    }
+
+    /**
+     * @return The number of passengers for whom a pickup
+     *         could not be found.
+     */
+    public int getMissedPickups()
+    {
+        return missedPickups;
+    }
+
+    /**
+     * Create a new passenger with distinct pickup and
+     * destination locations.
+     * @return The created passenger.
+     */
+    private Passenger createPassenger()
+    {
+        int cityWidth = city.getWidth();
+        int cityHeight = city.getHeight();
+
+        Location pickupLocation =
+                    new Location(rand.nextInt(cityWidth),
+                                 rand.nextInt(cityHeight));
+        Location destination;
+        do{
+            destination =
+                    new Location(rand.nextInt(cityWidth),
+                                 rand.nextInt(cityHeight));
+        } while(pickupLocation.equals(destination));
+        return new Passenger(pickupLocation, destination);
+    }
+}

Semester 1/Programming 1/Java/examples/projects/chapter16/taxi-company-later-stage/README.TXT

@@ -0,0 +1,21 @@
+Project: taxi-company-later-stage
+Authors: David J. Barnes and Michael Kölling
+
+This project is part of the material for chapter 14 of the book
+
+   Objects First with Java - A Practical Introduction using BlueJ
+   Sixth edition
+   David J. Barnes and Michael Kölling
+   Pearson Education, 2016
+
+This project provides a partial implementation of a simulation of
+taxis operating on a city grid to pick up and transport passengers.
+    
+This is the fourth stage of this project. It illustrates the 
+implementation of operation with multiple taxis.
+
+How to start this project:
+    Create a Simulation object and invoke its run method.
+
+Use this version to explore further development ideas, such
+as implementation of the Shuttle class.

Semester 1/Programming 1/Java/examples/projects/chapter16/taxi-company-later-stage/Shuttle.ctxt

@@ -0,0 +1,23 @@
+#BlueJ class context
+comment0.params=company\ location
+comment0.target=Shuttle(TaxiCompany,\ Location)
+comment0.text=\n\ Constructor\ for\ objects\ of\ class\ Shuttle\n\ @param\ company\ The\ taxi\ company.\ Must\ not\ be\ null.\n\ @param\ location\ The\ vehicle's\ starting\ point.\ Must\ not\ be\ null.\n\ @throws\ NullPointerException\ If\ company\ or\ location\ is\ null.\n
+comment1.params=
+comment1.target=void\ act()
+comment1.text=\n\ Carry\ out\ a\ shuttle's\ actions.\n
+comment2.params=
+comment2.target=boolean\ isFree()
+comment2.text=\n\ Is\ the\ shuttle\ free?\n\ @return\ Whether\ or\ not\ this\ vehicle\ is\ free.\n
+comment3.params=location
+comment3.target=void\ setPickupLocation(Location)
+comment3.text=\n\ Receive\ a\ pickup\ location.\n\ @param\ location\ The\ pickup\ location.\n
+comment4.params=passenger
+comment4.target=void\ pickup(Passenger)
+comment4.text=\n\ Receive\ a\ passenger.\n\ Add\ their\ destination\ to\ the\ list.\n\ @param\ passenger\ The\ passenger.\n
+comment5.params=
+comment5.target=void\ chooseTargetLocation()
+comment5.text=\n\ Decide\ where\ to\ go\ next,\ based\ on\ the\ list\ of\n\ possible\ destinations.\n
+comment6.params=
+comment6.target=void\ offloadPassenger()
+comment6.text=\n\ Offload\ a\ passenger\ whose\ destination\ is\ the\n\ current\ location.\n
+numComments=7

Semester 1/Programming 1/Java/examples/projects/chapter16/taxi-company-later-stage/Shuttle.java

@@ -0,0 +1,84 @@
+import java.util.List;
+import java.util.LinkedList;
+    
+/**
+ * A shuttle is able to carry multiple passengers.
+ * This implementation is non-functional.
+ * 
+ * @author David J. Barnes and Michael Kölling
+ * @version 2016.02.29
+ */
+public class Shuttle extends Vehicle
+{
+    // The list of destinations for the shuttle.
+    private List<Location> destinations;
+    // The list of passengers on the shuttle.
+    private List<Passenger> passengers;
+
+    /**
+     * Constructor for objects of class Shuttle
+     * @param company The taxi company. Must not be null.
+     * @param location The vehicle's starting point. Must not be null.
+     * @throws NullPointerException If company or location is null.
+     */
+    public Shuttle(TaxiCompany company, Location location)
+    {
+        super(company, location);
+        destinations = new LinkedList<>();
+        passengers = new LinkedList<>();
+    }
+
+    /**
+     * Carry out a shuttle's actions.
+     */
+    public void act()
+    {
+    }
+
+    /**
+     * Is the shuttle free?
+     * @return Whether or not this vehicle is free.
+     */
+    public boolean isFree()
+    {
+        return true;
+    }
+    
+    /**
+     * Receive a pickup location.
+     * @param location The pickup location.
+     */
+    public void setPickupLocation(Location location)
+    {
+        destinations.add(location);
+        chooseTargetLocation();
+    }
+    
+    /**
+     * Receive a passenger.
+     * Add their destination to the list.
+     * @param passenger The passenger.
+     */
+    public void pickup(Passenger passenger)
+    {
+        passengers.add(passenger);
+        destinations.add(passenger.getDestination());
+        chooseTargetLocation();
+    }
+
+    /**
+     * Decide where to go next, based on the list of
+     * possible destinations.
+     */
+    private void chooseTargetLocation()
+    {
+    }
+
+    /**
+     * Offload a passenger whose destination is the
+     * current location.
+     */
+    public void offloadPassenger()
+    {
+    }
+}

Semester 1/Programming 1/Java/examples/projects/chapter16/taxi-company-later-stage/Simulation.ctxt

@@ -0,0 +1,14 @@
+#BlueJ class context
+comment0.params=
+comment0.target=Simulation()
+comment0.text=\n\ Create\ the\ initial\ set\ of\ actors\ for\ the\ simulation.\n
+comment1.params=
+comment1.target=void\ run()
+comment1.text=\n\ Run\ the\ simulation\ for\ a\ fixed\ number\ of\ steps.\n\ Pause\ after\ each\ step\ to\ allow\ the\ GUI\ to\ keep\ up.\n
+comment2.params=
+comment2.target=void\ step()
+comment2.text=\n\ Take\ a\ single\ step\ of\ the\ simulation.\n
+comment3.params=milliseconds
+comment3.target=void\ wait(int)
+comment3.text=\n\ Wait\ for\ a\ specified\ number\ of\ milliseconds\ before\ finishing.\n\ This\ provides\ an\ easy\ way\ to\ cause\ a\ small\ delay.\n\ @param\ milliseconds\ The\ number\ of\ milliseconds\ to\ wait.\n
+numComments=4

Semester 1/Programming 1/Java/examples/projects/chapter16/taxi-company-later-stage/Simulation.java

@@ -0,0 +1,71 @@
+import java.util.Iterator;
+import java.util.LinkedList;
+import java.util.List;
+
+/**
+ * Run the simulation by asking a collection of actors to act.
+ * 
+ * @author David J. Barnes and Michael Kölling
+ * @version 2016.02.29
+ */
+public class Simulation
+{
+    private List<Actor> actors;
+    private int step;
+
+    /**
+     * Create the initial set of actors for the simulation.
+     */
+    public Simulation()
+    {
+        actors = new LinkedList<>();
+        step = 0;
+        City city = new City();
+        TaxiCompany company = new TaxiCompany(city);
+        PassengerSource source = new PassengerSource(city, company);
+        
+        actors.addAll(company.getVehicles());
+        actors.add(source);
+        actors.add(new CityGUI(city));
+    }
+    
+    /**
+     * Run the simulation for a fixed number of steps.
+     * Pause after each step to allow the GUI to keep up.
+     */
+    public void run()
+    {
+        for(int i = 0; i < 500; i++){
+            step++;
+            step();
+            wait(100);
+        }
+    }
+
+    /**
+     * Take a single step of the simulation.
+     */
+    public void step()
+    {
+        for(Actor actor : actors) {
+            actor.act();
+        }
+    }
+    
+    /**
+     * Wait for a specified number of milliseconds before finishing.
+     * This provides an easy way to cause a small delay.
+     * @param milliseconds The number of milliseconds to wait.
+     */
+    private void wait(int milliseconds)
+    {
+        try
+        {
+            Thread.sleep(milliseconds);
+        } 
+        catch (InterruptedException e)
+        {
+            // ignore the exception
+        }
+    }
+}

Semester 1/Programming 1/Java/examples/projects/chapter16/taxi-company-later-stage/Taxi.ctxt

@@ -0,0 +1,26 @@
+#BlueJ class context
+comment0.params=company\ location
+comment0.target=Taxi(TaxiCompany,\ Location)
+comment0.text=\n\ Constructor\ for\ objects\ of\ class\ Taxi\n\ @param\ company\ The\ taxi\ company.\ Must\ not\ be\ null.\n\ @param\ location\ The\ vehicle's\ starting\ point.\ Must\ not\ be\ null.\n\ @throws\ NullPointerException\ If\ company\ or\ location\ is\ null.\n
+comment1.params=
+comment1.target=void\ act()
+comment1.text=\n\ Move\ towards\ the\ target\ location\ if\ we\ have\ one.\n\ Otherwise\ record\ that\ we\ are\ idle.\n
+comment2.params=
+comment2.target=boolean\ isFree()
+comment2.text=\n\ Is\ the\ taxi\ free?\n\ @return\ Whether\ or\ not\ this\ taxi\ is\ free.\n
+comment3.params=location
+comment3.target=void\ setPickupLocation(Location)
+comment3.text=\n\ Receive\ a\ pickup\ location.\ This\ becomes\ the\n\ target\ location.\n\ @param\ location\ The\ pickup\ location.\n
+comment4.params=passenger
+comment4.target=void\ pickup(Passenger)
+comment4.text=\n\ Receive\ a\ passenger.\n\ Set\ their\ destination\ as\ the\ target\ location.\n\ @param\ passenger\ The\ passenger.\n
+comment5.params=
+comment5.target=void\ offloadPassenger()
+comment5.text=\n\ Offload\ the\ passenger.\n
+comment6.params=
+comment6.target=java.awt.Image\ getImage()
+comment6.text=\n\ Return\ an\ image\ that\ describes\ our\ state\:\n\ either\ empty\ or\ carrying\ a\ passenger.\n
+comment7.params=
+comment7.target=java.lang.String\ toString()
+comment7.text=\n\ Return\ details\ of\ the\ taxi,\ such\ as\ where\ it\ is.\n\ @return\ A\ string\ representation\ of\ the\ taxi.\n
+numComments=8

Semester 1/Programming 1/Java/examples/projects/chapter16/taxi-company-later-stage/Taxi.java

@@ -0,0 +1,121 @@
+import java.awt.Image;
+import javax.swing.ImageIcon;
+
+/**
+ * A taxi is able to carry a single passenger.
+ * 
+ * @author David J. Barnes and Michael Kölling
+ * @version 2016.02.29
+ */
+public class Taxi extends Vehicle implements DrawableItem
+{
+    private Passenger passenger;
+    // Maintain separate images for when the taxi is empty
+    // and full.
+    private Image emptyImage, passengerImage;
+    
+    /**
+     * Constructor for objects of class Taxi
+     * @param company The taxi company. Must not be null.
+     * @param location The vehicle's starting point. Must not be null.
+     * @throws NullPointerException If company or location is null.
+     */
+    public Taxi(TaxiCompany company, Location location)
+    {
+        super(company, location);
+    // Load the two images.
+        emptyImage = new ImageIcon(getClass().getResource(
+                                "images/taxi.jpg")).getImage();
+
+        passengerImage = new ImageIcon(getClass().getResource(
+                                "images/taxi+person.jpg")).getImage();
+    }
+    
+    /**
+     * Move towards the target location if we have one.
+     * Otherwise record that we are idle.
+     */
+    public void act()
+    {
+        Location target = getTargetLocation();
+        if(target != null) {
+            // Find where to move to next.
+            Location next = getLocation().nextLocation(target);
+            setLocation(next);
+            if(next.equals(target)) {
+                if(passenger != null) {
+                    notifyPassengerArrival(passenger);
+                    offloadPassenger();
+                }
+                else {
+                    notifyPickupArrival();
+                }
+            }
+        }
+        else {
+            incrementIdleCount();
+        }
+    }
+
+    /**
+     * Is the taxi free?
+     * @return Whether or not this taxi is free.
+     */
+    public boolean isFree()
+    {
+        return getTargetLocation() == null && passenger == null;
+    }
+    
+    /**
+     * Receive a pickup location. This becomes the
+     * target location.
+     * @param location The pickup location.
+     */
+    public void setPickupLocation(Location location)
+    {
+        setTargetLocation(location);
+    }
+    
+    /**
+     * Receive a passenger.
+     * Set their destination as the target location.
+     * @param passenger The passenger.
+     */
+    public void pickup(Passenger passenger)
+    {
+        this.passenger = passenger;
+        setTargetLocation(passenger.getDestination());
+    }
+
+    /**
+     * Offload the passenger.
+     */
+    public void offloadPassenger()
+    {
+        passenger = null;
+        clearTargetLocation();
+    }
+    
+    /**
+     * Return an image that describes our state:
+     * either empty or carrying a passenger.
+     */
+    public Image getImage()
+    {
+        if(passenger != null) {
+            return passengerImage;
+        }
+        else {
+            return emptyImage;
+        }
+    }
+
+    /**
+     * Return details of the taxi, such as where it is.
+     * @return A string representation of the taxi.
+     */
+    public String toString()
+    {
+        return "Taxi at " + getLocation();
+    }
+}

Semester 1/Programming 1/Java/examples/projects/chapter16/taxi-company-later-stage/TaxiCompany.ctxt

@@ -0,0 +1,23 @@
+#BlueJ class context
+comment0.params=city
+comment0.target=TaxiCompany(City)
+comment0.text=\n\ @param\ city\ The\ city.\n
+comment1.params=passenger
+comment1.target=boolean\ requestPickup(Passenger)
+comment1.text=\n\ Request\ a\ pickup\ for\ the\ given\ passenger.\n\ @param\ passenger\ The\ passenger\ requesting\ a\ pickup.\n\ @return\ Whether\ a\ free\ vehicle\ is\ available.\n
+comment2.params=vehicle
+comment2.target=void\ arrivedAtPickup(Vehicle)
+comment2.text=\n\ A\ vehicle\ has\ arrived\ at\ a\ pickup\ point.\n\ @param\ vehicle\ The\ vehicle\ at\ the\ pickup\ point.\n\ @throws\ MissingPassengerException\ If\ there\ is\ no\ passenger\ waiting.\n
+comment3.params=vehicle\ passenger
+comment3.target=void\ arrivedAtDestination(Vehicle,\ Passenger)
+comment3.text=\n\ A\ vehicle\ has\ arrived\ at\ a\ passenger's\ destination.\n\ @param\ vehicle\ The\ vehicle\ at\ the\ destination.\n\ @param\ passenger\ The\ passenger\ being\ dropped\ off.\n
+comment4.params=
+comment4.target=java.util.List\ getVehicles()
+comment4.text=\n\ @return\ The\ list\ of\ vehicles.\n
+comment5.params=
+comment5.target=Vehicle\ scheduleVehicle()
+comment5.text=\n\ Find\ a\ free\ vehicle,\ if\ any.\n\ @return\ A\ free\ vehicle,\ or\ null\ if\ there\ is\ none.\n
+comment6.params=
+comment6.target=void\ setupVehicles()
+comment6.text=\n\ Set\ up\ this\ company's\ vehicles.\ The\ optimum\ number\ of\n\ vehicles\ should\ be\ determined\ by\ analysis\ of\ the\n\ data\ gathered\ from\ the\ simulation.\n\n\ Vehicles\ start\ at\ random\ locations.\n
+numComments=7

Semester 1/Programming 1/Java/examples/projects/chapter16/taxi-company-later-stage/TaxiCompany.java

@@ -0,0 +1,129 @@
+import java.util.HashMap;
+import java.util.Iterator;
+import java.util.List;
+import java.util.LinkedList;
+import java.util.Map;
+import java.util.Random;
+
+/**
+ * Model the operation of a taxi company, operating different
+ * types of vehicle. This version operates a only taxis.
+ * 
+ * @author David J. Barnes and Michael Kölling
+ * @version 2016.02.29
+ */
+public class TaxiCompany  
+{
+    // The vehicles operated by the company.
+    private List<Vehicle> vehicles;
+    private City city;
+    // The associations between vehicles and the passengers
+    // they are to pick up.
+    private Map<Vehicle, Passenger> assignments;
+
+    private static final int NUMBER_OF_TAXIS = 3;
+
+    /**
+     * @param city The city.
+     */
+    public TaxiCompany(City city)
+    {
+        this.city = city;
+        vehicles = new LinkedList<>();
+        assignments = new HashMap<>();
+        setupVehicles();
+    }
+
+    /**
+     * Request a pickup for the given passenger.
+     * @param passenger The passenger requesting a pickup.
+     * @return Whether a free vehicle is available.
+     */
+    public boolean requestPickup(Passenger passenger)
+    {
+        Vehicle vehicle = scheduleVehicle();
+        if(vehicle != null) {
+            assignments.put(vehicle, passenger);
+            vehicle.setPickupLocation(passenger.getPickupLocation());
+            return true;
+        }
+        else {
+            return false;
+        }
+    }
+    
+    /**
+     * A vehicle has arrived at a pickup point.
+     * @param vehicle The vehicle at the pickup point.
+     * @throws MissingPassengerException If there is no passenger waiting.
+     */
+    public void arrivedAtPickup(Vehicle vehicle)
+    {
+        Passenger passenger = assignments.remove(vehicle);
+        if(passenger == null) {
+            throw new MissingPassengerException(vehicle);
+        }
+        city.removeItem(passenger);
+        vehicle.pickup(passenger);
+    }
+    
+    /**
+     * A vehicle has arrived at a passenger's destination.
+     * @param vehicle The vehicle at the destination.
+     * @param passenger The passenger being dropped off.
+     */
+    public void arrivedAtDestination(Vehicle vehicle,
+                                     Passenger passenger)
+    {
+    }
+    
+    /**
+     * @return The list of vehicles.
+     */
+    public List<Vehicle> getVehicles()
+    {
+        return vehicles;
+    }
+    
+    /**
+     * Find a free vehicle, if any.
+     * @return A free vehicle, or null if there is none.
+     */
+    private Vehicle scheduleVehicle()
+    {
+        Iterator<Vehicle> it = vehicles.iterator();
+        while(it.hasNext()) {
+            Vehicle vehicle = it.next();
+            if(vehicle.isFree()) {
+                return vehicle;
+            }
+        }
+        return null;
+    }
+
+    /**
+     * Set up this company's vehicles. The optimum number of
+     * vehicles should be determined by analysis of the
+     * data gathered from the simulation.
+     *
+     * Vehicles start at random locations.
+     */
+    private void setupVehicles()
+    {
+        int cityWidth = city.getWidth();
+        int cityHeight = city.getHeight();
+        // Used a fixed random seed for predictable behavior.
+        // Use different seeds for less predictable behavior.
+        Random rand = new Random(12345);
+
+        // Create the taxis.
+        for(int i = 0; i < NUMBER_OF_TAXIS; i++){
+            Taxi taxi =
+                new Taxi(this,
+                         new Location(rand.nextInt(cityWidth),
+                                      rand.nextInt(cityHeight)));
+            vehicles.add(taxi);
+            city.addItem(taxi);
+        }
+   }
+}

Semester 1/Programming 1/Java/examples/projects/chapter16/taxi-company-later-stage/Vehicle.ctxt

@@ -0,0 +1,44 @@
+#BlueJ class context
+comment0.params=company\ location
+comment0.target=Vehicle(TaxiCompany,\ Location)
+comment0.text=\n\ Constructor\ of\ class\ Vehicle\n\ @param\ company\ The\ taxi\ company.\ Must\ not\ be\ null.\n\ @param\ location\ The\ vehicle's\ starting\ point.\ Must\ not\ be\ null.\n\ @throws\ NullPointerException\ If\ company\ or\ location\ is\ null.\n
+comment1.params=
+comment1.target=void\ notifyPickupArrival()
+comment1.text=\n\ Notify\ the\ company\ of\ our\ arrival\ at\ a\ pickup\ location.\n
+comment10.params=location
+comment10.target=void\ setTargetLocation(Location)
+comment10.text=\n\ Set\ the\ required\ target\ location.\n\ @param\ location\ Where\ to\ go.\ Must\ not\ be\ null.\n\ @throws\ NullPointerException\ If\ location\ is\ null.\n
+comment11.params=
+comment11.target=void\ clearTargetLocation()
+comment11.text=\n\ Clear\ the\ target\ location.\n
+comment12.params=
+comment12.target=int\ getIdleCount()
+comment12.text=\n\ @return\ On\ how\ many\ steps\ this\ vehicle\ has\ been\ idle.\n
+comment13.params=
+comment13.target=void\ incrementIdleCount()
+comment13.text=\n\ Increment\ the\ number\ of\ steps\ on\ which\ this\ vehicle\n\ has\ been\ idle.\n
+comment2.params=passenger
+comment2.target=void\ notifyPassengerArrival(Passenger)
+comment2.text=\n\ Notify\ the\ company\ of\ our\ arrival\ at\ a\n\ passenger's\ destination.\n
+comment3.params=location
+comment3.target=void\ setPickupLocation(Location)
+comment3.text=\n\ Receive\ a\ pickup\ location.\n\ How\ this\ is\ handled\ depends\ on\ the\ type\ of\ vehicle.\n\ @param\ location\ The\ pickup\ location.\n
+comment4.params=passenger
+comment4.target=void\ pickup(Passenger)
+comment4.text=\n\ Receive\ a\ passenger.\n\ How\ this\ is\ handled\ depends\ on\ the\ type\ of\ vehicle.\n\ @param\ passenger\ The\ passenger.\n
+comment5.params=
+comment5.target=boolean\ isFree()
+comment5.text=\n\ Is\ the\ vehicle\ free?\n\ @return\ Whether\ or\ not\ this\ vehicle\ is\ free.\n
+comment6.params=
+comment6.target=void\ offloadPassenger()
+comment6.text=\n\ Offload\ any\ passengers\ whose\ destination\ is\ the\n\ current\ location.\n
+comment7.params=
+comment7.target=Location\ getLocation()
+comment7.text=\n\ @return\ Where\ this\ vehicle\ is\ currently\ located.\n
+comment8.params=location
+comment8.target=void\ setLocation(Location)
+comment8.text=\n\ Set\ the\ current\ location.\n\ @param\ location\ Where\ it\ is.\ Must\ not\ be\ null.\n\ @throws\ NullPointerException\ If\ location\ is\ null.\n
+comment9.params=
+comment9.target=Location\ getTargetLocation()
+comment9.text=\n\ Get\ the\ target\ location.\n\ @return\ Where\ this\ vehicle\ is\ currently\ headed,\ or\ null\n\ \ \ \ \ \ \ \ \ if\ it\ is\ idle.\n
+numComments=14

Semester 1/Programming 1/Java/examples/projects/chapter16/taxi-company-later-stage/Vehicle.java

@@ -0,0 +1,152 @@
+/**
+ * Model the common elements of taxis and shuttles.
+ * 
+ * @author David J. Barnes and Michael Kölling
+ * @version 2016.02.29
+ */
+public abstract class Vehicle implements Actor
+{
+    private TaxiCompany company;
+    // Where the vehicle is.
+    private Location location;
+    // Where the vehicle is headed.
+    private Location targetLocation;
+    // Record how often the vehicle has nothing to do.
+    private int idleCount;
+    
+    /**
+     * Constructor of class Vehicle
+     * @param company The taxi company. Must not be null.
+     * @param location The vehicle's starting point. Must not be null.
+     * @throws NullPointerException If company or location is null.
+     */
+    public Vehicle(TaxiCompany company, Location location)
+    {
+        if(company == null) {
+            throw new NullPointerException("company");
+        }
+        if(location == null) {
+            throw new NullPointerException("location");
+        }
+        this.company = company;
+        this.location = location;
+        targetLocation = null;
+        idleCount = 0;
+    }
+    
+    /**
+     * Notify the company of our arrival at a pickup location.
+     */
+    public void notifyPickupArrival()
+    {
+        company.arrivedAtPickup(this);
+    }
+    
+    /**
+     * Notify the company of our arrival at a
+     * passenger's destination.
+     */
+    public void notifyPassengerArrival(Passenger passenger)
+    {
+        company.arrivedAtDestination(this, passenger);
+    }
+    
+    /**
+     * Receive a pickup location.
+     * How this is handled depends on the type of vehicle.
+     * @param location The pickup location.
+     */
+    public abstract void setPickupLocation(Location location);
+    
+    /**
+     * Receive a passenger.
+     * How this is handled depends on the type of vehicle.
+     * @param passenger The passenger.
+     */
+    public abstract void pickup(Passenger passenger);
+    
+    /**
+     * Is the vehicle free?
+     * @return Whether or not this vehicle is free.
+     */
+    public abstract boolean isFree();
+    
+    /**
+     * Offload any passengers whose destination is the
+     * current location.
+     */
+    public abstract void offloadPassenger();
+    
+    /**
+     * @return Where this vehicle is currently located.
+     */
+    public Location getLocation()
+    {
+        return location;
+    }
+    
+    /**
+     * Set the current location.
+     * @param location Where it is. Must not be null.
+     * @throws NullPointerException If location is null.
+     */
+    public void setLocation(Location location)
+    {
+        if(location != null) {
+            this.location = location;
+        }
+        else {
+            throw new NullPointerException();
+        }
+    }
+    
+    /**
+     * Get the target location.
+     * @return Where this vehicle is currently headed, or null
+     *         if it is idle.
+     */
+    public Location getTargetLocation()
+    {
+        return targetLocation;
+    }
+    
+    /**
+     * Set the required target location.
+     * @param location Where to go. Must not be null.
+     * @throws NullPointerException If location is null.
+     */
+    public void setTargetLocation(Location location)
+    {
+        if(location != null) {
+            targetLocation = location;
+        }
+        else {
+            throw new NullPointerException();
+        }
+    }
+    
+    /**
+     * Clear the target location.
+     */
+    public void clearTargetLocation()
+    {
+        targetLocation = null;
+    }
+
+    /**
+     * @return On how many steps this vehicle has been idle.
+     */
+    public int getIdleCount()
+    {
+        return idleCount;
+    }
+    
+    /**
+     * Increment the number of steps on which this vehicle
+     * has been idle.
+     */
+    public void incrementIdleCount()
+    {
+        idleCount++;
+    }
+}

Semester 1/Programming 1/Java/examples/projects/chapter16/taxi-company-later-stage/package.bluej

@@ -0,0 +1,294 @@
+#BlueJ package file
+dependency1.from=Shuttle
+dependency1.to=TaxiCompany
+dependency1.type=UsesDependency
+dependency10.from=MissingPassengerException
+dependency10.to=Vehicle
+dependency10.type=UsesDependency
+dependency11.from=Taxi
+dependency11.to=Passenger
+dependency11.type=UsesDependency
+dependency12.from=Taxi
+dependency12.to=TaxiCompany
+dependency12.type=UsesDependency
+dependency13.from=Taxi
+dependency13.to=Location
+dependency13.type=UsesDependency
+dependency14.from=Item
+dependency14.to=Location
+dependency14.type=UsesDependency
+dependency15.from=TaxiCompany
+dependency15.to=City
+dependency15.type=UsesDependency
+dependency16.from=TaxiCompany
+dependency16.to=Passenger
+dependency16.type=UsesDependency
+dependency17.from=TaxiCompany
+dependency17.to=Vehicle
+dependency17.type=UsesDependency
+dependency18.from=TaxiCompany
+dependency18.to=MissingPassengerException
+dependency18.type=UsesDependency
+dependency19.from=TaxiCompany
+dependency19.to=Taxi
+dependency19.type=UsesDependency
+dependency2.from=Shuttle
+dependency2.to=Location
+dependency2.type=UsesDependency
+dependency20.from=TaxiCompany
+dependency20.to=Location
+dependency20.type=UsesDependency
+dependency21.from=CityGUI
+dependency21.to=City
+dependency21.type=UsesDependency
+dependency22.from=CityGUI
+dependency22.to=DrawableItem
+dependency22.type=UsesDependency
+dependency23.from=CityGUI
+dependency23.to=Location
+dependency23.type=UsesDependency
+dependency24.from=PassengerSource
+dependency24.to=City
+dependency24.type=UsesDependency
+dependency25.from=PassengerSource
+dependency25.to=TaxiCompany
+dependency25.type=UsesDependency
+dependency26.from=PassengerSource
+dependency26.to=Passenger
+dependency26.type=UsesDependency
+dependency27.from=PassengerSource
+dependency27.to=Location
+dependency27.type=UsesDependency
+dependency28.from=Vehicle
+dependency28.to=TaxiCompany
+dependency28.type=UsesDependency
+dependency29.from=Vehicle
+dependency29.to=Location
+dependency29.type=UsesDependency
+dependency3.from=Shuttle
+dependency3.to=Passenger
+dependency3.type=UsesDependency
+dependency30.from=Vehicle
+dependency30.to=Passenger
+dependency30.type=UsesDependency
+dependency31.from=City
+dependency31.to=Item
+dependency31.type=UsesDependency
+dependency32.from=CityGUI
+dependency32.to=Item
+dependency32.type=UsesDependency
+dependency4.from=Simulation
+dependency4.to=City
+dependency4.type=UsesDependency
+dependency5.from=Simulation
+dependency5.to=TaxiCompany
+dependency5.type=UsesDependency
+dependency6.from=Simulation
+dependency6.to=PassengerSource
+dependency6.type=UsesDependency
+dependency7.from=Simulation
+dependency7.to=CityGUI
+dependency7.type=UsesDependency
+dependency8.from=Simulation
+dependency8.to=Actor
+dependency8.type=UsesDependency
+dependency9.from=Passenger
+dependency9.to=Location
+dependency9.type=UsesDependency
+objectbench.height=76
+objectbench.width=1080
+package.editor.height=541
+package.editor.width=972
+package.editor.x=70
+package.editor.y=80
+package.numDependencies=32
+package.numTargets=14
+package.showExtends=true
+package.showUses=true
+project.charset=UTF-8
+readme.editor.height=567
+readme.editor.width=790
+readme.editor.x=53
+readme.editor.y=23
+target1.editor.height=700
+target1.editor.width=900
+target1.editor.x=53
+target1.editor.y=23
+target1.height=50
+target1.name=MissingPassengerException
+target1.naviview.expanded=true
+target1.showInterface=false
+target1.type=ClassTarget
+target1.typeParameters=
+target1.width=190
+target1.x=130
+target1.y=430
+target10.editor.height=734
+target10.editor.width=763
+target10.editor.x=53
+target10.editor.y=60
+target10.height=50
+target10.name=Taxi
+target10.naviview.expanded=false
+target10.showInterface=false
+target10.type=ClassTarget
+target10.typeParameters=
+target10.width=80
+target10.x=570
+target10.y=270
+target11.editor.height=700
+target11.editor.width=900
+target11.editor.x=53
+target11.editor.y=23
+target11.height=50
+target11.name=Passenger
+target11.naviview.expanded=true
+target11.showInterface=false
+target11.type=ClassTarget
+target11.typeParameters=
+target11.width=90
+target11.x=760
+target11.y=270
+target12.editor.height=730
+target12.editor.width=785
+target12.editor.x=53
+target12.editor.y=60
+target12.height=50
+target12.name=PassengerSource
+target12.naviview.expanded=true
+target12.showInterface=false
+target12.type=ClassTarget
+target12.typeParameters=
+target12.width=130
+target12.x=320
+target12.y=130
+target13.editor.height=702
+target13.editor.width=828
+target13.editor.x=53
+target13.editor.y=60
+target13.height=50
+target13.name=Shuttle
+target13.naviview.expanded=false
+target13.showInterface=false
+target13.type=ClassTarget
+target13.typeParameters=
+target13.width=80
+target13.x=430
+target13.y=270
+target14.editor.height=700
+target14.editor.width=900
+target14.editor.x=53
+target14.editor.y=23
+target14.height=50
+target14.name=Location
+target14.naviview.expanded=true
+target14.showInterface=false
+target14.type=ClassTarget
+target14.typeParameters=
+target14.width=80
+target14.x=690
+target14.y=410
+target2.editor.height=728
+target2.editor.width=797
+target2.editor.x=53
+target2.editor.y=60
+target2.height=50
+target2.name=City
+target2.naviview.expanded=true
+target2.showInterface=false
+target2.type=ClassTarget
+target2.typeParameters=
+target2.width=80
+target2.x=260
+target2.y=230
+target3.editor.height=700
+target3.editor.width=900
+target3.editor.x=53
+target3.editor.y=23
+target3.height=50
+target3.name=DrawableItem
+target3.naviview.expanded=true
+target3.showInterface=false
+target3.type=InterfaceTarget
+target3.typeParameters=
+target3.width=100
+target3.x=660
+target3.y=180
+target4.editor.height=719
+target4.editor.width=796
+target4.editor.x=53
+target4.editor.y=60
+target4.height=50
+target4.name=Vehicle
+target4.naviview.expanded=false
+target4.showInterface=false
+target4.type=AbstractTarget
+target4.typeParameters=
+target4.width=80
+target4.x=490
+target4.y=130
+target5.editor.height=700
+target5.editor.width=900
+target5.editor.x=53
+target5.editor.y=23
+target5.height=50
+target5.name=Item
+target5.naviview.expanded=true
+target5.showInterface=false
+target5.type=InterfaceTarget
+target5.typeParameters=
+target5.width=80
+target5.x=850
+target5.y=90
+target6.editor.height=724
+target6.editor.width=802
+target6.editor.x=53
+target6.editor.y=60
+target6.height=50
+target6.name=TaxiCompany
+target6.naviview.expanded=true
+target6.showInterface=false
+target6.type=ClassTarget
+target6.typeParameters=
+target6.width=100
+target6.x=110
+target6.y=320
+target7.editor.height=719
+target7.editor.width=829
+target7.editor.x=53
+target7.editor.y=60
+target7.height=50
+target7.name=Simulation
+target7.naviview.expanded=true
+target7.showInterface=false
+target7.type=ClassTarget
+target7.typeParameters=
+target7.width=80
+target7.x=60
+target7.y=20
+target8.editor.height=735
+target8.editor.width=648
+target8.editor.x=53
+target8.editor.y=60
+target8.height=50
+target8.name=Actor
+target8.naviview.expanded=true
+target8.showInterface=false
+target8.type=InterfaceTarget
+target8.typeParameters=
+target8.width=80
+target8.x=330
+target8.y=30
+target9.editor.height=732
+target9.editor.width=974
+target9.editor.x=64
+target9.editor.y=83
+target9.height=50
+target9.name=CityGUI
+target9.naviview.expanded=true
+target9.showInterface=false
+target9.type=ClassTarget
+target9.typeParameters=
+target9.width=80
+target9.x=190
+target9.y=130

Semester 1/Programming 1/Java/examples/projects/chapter16/taxi-company-outline-testing/Location.ctxt

@@ -0,0 +1,5 @@
+#BlueJ class context
+comment0.params=
+comment0.target=Location()
+comment0.text=\n\ Constructor\ for\ objects\ of\ class\ Location\n
+numComments=1

Semester 1/Programming 1/Java/examples/projects/chapter16/taxi-company-outline-testing/Location.java

@@ -0,0 +1,15 @@
+/**
+ * Model a location in a city.
+ * 
+ * @author David J. Barnes and Michael Kölling
+ * @version 2016.02.29
+ */
+public class Location
+{
+    /**
+     * Constructor for objects of class Location
+     */
+    public Location()
+    {
+    }
+}

Semester 1/Programming 1/Java/examples/projects/chapter16/taxi-company-outline-testing/Passenger.ctxt

@@ -0,0 +1,11 @@
+#BlueJ class context
+comment0.params=pickup\ destination
+comment0.target=Passenger(Location,\ Location)
+comment0.text=\n\ Constructor\ for\ objects\ of\ class\ Passenger\n\ @param\ pickup\ The\ pickup\ location,\ must\ not\ be\ null.\n\ @param\ destination\ The\ destination\ location,\ must\ not\ be\ null.\n\ @throws\ NullPointerException\ If\ either\ location\ is\ null.\n
+comment1.params=
+comment1.target=Location\ getPickupLocation()
+comment1.text=\n\ @return\ The\ pickup\ location.\n
+comment2.params=
+comment2.target=Location\ getDestination()
+comment2.text=\n\ @return\ The\ destination\ location.\n
+numComments=3

Semester 1/Programming 1/Java/examples/projects/chapter16/taxi-company-outline-testing/Passenger.java

@@ -0,0 +1,46 @@
+/**
+ * Model a passenger wishing to get from one
+ * location to another.
+ * 
+ * @author David J. Barnes and Michael Kölling
+ * @version 2016.02.29
+ */
+public class Passenger
+{
+    private Location pickup;
+    private Location destination;
+
+    /**
+     * Constructor for objects of class Passenger
+     * @param pickup The pickup location, must not be null.
+     * @param destination The destination location, must not be null.
+     * @throws NullPointerException If either location is null.
+     */
+    public Passenger(Location pickup, Location destination)
+    {
+        if(pickup == null) {
+            throw new NullPointerException("Pickup location");
+        }
+        if(destination == null) {
+            throw new NullPointerException("Destination location");
+        }
+        this.pickup = pickup;
+        this.destination = destination;
+    }
+
+    /**
+     * @return The pickup location.
+     */
+    public Location getPickupLocation()
+    {
+        return pickup;
+    }
+    
+    /**
+     * @return The destination location.
+     */
+    public Location getDestination()
+    {
+        return destination;
+    }
+}

Semester 1/Programming 1/Java/examples/projects/chapter16/taxi-company-outline-testing/PassengerSource.ctxt

@@ -0,0 +1,11 @@
+#BlueJ class context
+comment0.params=company
+comment0.target=PassengerSource(TaxiCompany)
+comment0.text=\n\ Constructor\ for\ objects\ of\ class\ PassengerSource.\n\ @param\ company\ The\ company\ to\ be\ used.\ Must\ not\ be\ null.\n\ @throws\ NullPointerException\ if\ company\ is\ null.\n
+comment1.params=
+comment1.target=boolean\ requestPickup()
+comment1.text=\n\ Have\ the\ source\ generate\ a\ new\ passenger\ and\n\ request\ a\ pickup\ from\ the\ company.\n\ @return\ true\ If\ the\ request\ succeeds,\ false\ otherwise.\n
+comment2.params=
+comment2.target=Passenger\ createPassenger()
+comment2.text=\n\ Create\ a\ new\ passenger.\n\ @return\ The\ created\ passenger.\n
+numComments=3

Semester 1/Programming 1/Java/examples/projects/chapter16/taxi-company-outline-testing/PassengerSource.java

@@ -0,0 +1,44 @@
+/**
+ * Simulate passengers requesting rides from a taxi company.
+ * Passengers should be generated at random intervals.
+ * 
+ * @author David J. Barnes and Michael Kölling
+ * @version 2016.02.29
+ */
+public class PassengerSource
+{
+    private TaxiCompany company;
+
+    /**
+     * Constructor for objects of class PassengerSource.
+     * @param company The company to be used. Must not be null.
+     * @throws NullPointerException if company is null.
+     */
+    public PassengerSource(TaxiCompany company)
+    {
+        if(company == null) {
+            throw new NullPointerException("company");
+        }
+        this.company = company;
+    }
+
+    /**
+     * Have the source generate a new passenger and
+     * request a pickup from the company.
+     * @return true If the request succeeds, false otherwise.
+     */
+    public boolean requestPickup()
+    {
+        Passenger passenger = createPassenger();
+        return company.requestPickup(passenger);
+    }
+
+    /**
+     * Create a new passenger.
+     * @return The created passenger.
+     */
+    private Passenger createPassenger()
+    {
+        return new Passenger(new Location(), new Location());
+    }
+}

Semester 1/Programming 1/Java/examples/projects/chapter16/taxi-company-outline-testing/PassengerSourceTest.ctxt

@@ -0,0 +1,14 @@
+#BlueJ class context
+comment0.params=
+comment0.target=PassengerSourceTest()
+comment0.text=\n\ Default\ constructor\ for\ test\ class\ PassengerSourceTest\n
+comment1.params=
+comment1.target=void\ setUp()
+comment1.text=\n\ Sets\ up\ the\ test\ fixture.\n\n\ Called\ before\ every\ test\ case\ method.\n
+comment2.params=
+comment2.target=void\ tearDown()
+comment2.text=\n\ Tears\ down\ the\ test\ fixture.\n\n\ Called\ after\ every\ test\ case\ method.\n
+comment3.params=
+comment3.target=void\ testPickup()
+comment3.text=\n\ Test\ for\ successful\ pickup\ of\ a\ passenger.\n
+numComments=4

Semester 1/Programming 1/Java/examples/projects/chapter16/taxi-company-outline-testing/PassengerSourceTest.java

@@ -0,0 +1,55 @@
+import static org.junit.Assert.*;
+import org.junit.After;
+import org.junit.Before;
+import org.junit.Test;
+
+/**
+ * The test class PassengerSourceTest.
+ *
+ * @author David J. Barnes and Michael Kölling
+ * @version 2016.02.29
+ */
+public class PassengerSourceTest
+{
+    private PassengerSource source;
+    
+    /**
+     * Default constructor for test class PassengerSourceTest
+     */
+    public PassengerSourceTest()
+    {
+    }
+
+    /**
+     * Sets up the test fixture.
+     *
+     * Called before every test case method.
+     */
+    @Before
+    public void setUp()
+    {
+        TaxiCompany company = new TaxiCompany();
+        source = new PassengerSource(company);
+    }
+
+    /**
+     * Tears down the test fixture.
+     *
+     * Called after every test case method.
+     */
+    @After
+    public void tearDown()
+    {
+        source = null;
+    }
+
+    /**
+     * Test for successful pickup of a passenger.
+     */
+    @Test
+    public void testPickup()
+    {
+        assertEquals(true, source.requestPickup());
+    }
+}
+

Semester 1/Programming 1/Java/examples/projects/chapter16/taxi-company-outline-testing/PassengerTest.ctxt

@@ -0,0 +1,14 @@
+#BlueJ class context
+comment0.params=
+comment0.target=PassengerTest()
+comment0.text=\n\ Default\ constructor\ for\ test\ class\ PassengerTest\n
+comment1.params=
+comment1.target=void\ setUp()
+comment1.text=\n\ Sets\ up\ the\ test\ fixture.\n\n\ Called\ before\ every\ test\ case\ method.\n
+comment2.params=
+comment2.target=void\ tearDown()
+comment2.text=\n\ Tears\ down\ the\ test\ fixture.\n\n\ Called\ after\ every\ test\ case\ method.\n
+comment3.params=
+comment3.target=void\ testCreation()
+comment3.text=\n\ Test\ basic\ creation\ of\ a\ passenger.\n\ Ensure\ that\ the\ pickup\ and\ destination\ locations\n\ have\ been\ set.\n
+numComments=4

Semester 1/Programming 1/Java/examples/projects/chapter16/taxi-company-outline-testing/PassengerTest.java

@@ -0,0 +1,57 @@
+import static org.junit.Assert.*;
+import org.junit.After;
+import org.junit.Before;
+import org.junit.Test;
+
+/**
+ * The test class PassengerTest.
+ *
+ * @author  David J. Barnes and Michael Kölling
+ * @version 2016.02.29
+ */
+public class PassengerTest
+{
+    /**
+     * Default constructor for test class PassengerTest
+     */
+    public PassengerTest()
+    {
+    }
+
+    /**
+     * Sets up the test fixture.
+     *
+     * Called before every test case method.
+     */
+    @Before
+    public void setUp()
+    {
+    }
+
+    /**
+     * Tears down the test fixture.
+     *
+     * Called after every test case method.
+     */
+    @After
+    public void tearDown()
+    {
+    }
+
+    /**
+     * Test basic creation of a passenger.
+     * Ensure that the pickup and destination locations
+     * have been set.
+     */
+    @Test
+	public void testCreation()
+	{
+		Location pickup = new Location();
+		Location destination = new Location();
+		Passenger passenger1 = new Passenger(pickup, destination);
+		assertEquals(destination, passenger1.getDestination());
+		assertEquals(pickup, passenger1.getPickupLocation());
+	}
+}
+
+

Semester 1/Programming 1/Java/examples/projects/chapter16/taxi-company-outline-testing/README.TXT

@@ -0,0 +1,16 @@
+Project: taxi-company-outline-testing
+Authors: David J. Barnes and Michael Kölling
+
+This project is part of the material for chapter 14 of the book
+
+   Objects First with Java - A Practical Introduction using BlueJ
+   Sixth edition
+   David J. Barnes and Michael Kölling
+   Pearson Education, 2016
+
+This project provides a partial implementation of a simulation of
+taxis operating on a city grid to pick up and transport passengers.
+    
+This is the second stage of this project. It illustrates some basic
+testing of the outline implementation.
+

Semester 1/Programming 1/Java/examples/projects/chapter16/taxi-company-outline-testing/Shuttle.ctxt

@@ -0,0 +1,20 @@
+#BlueJ class context
+comment0.params=company\ location
+comment0.target=Shuttle(TaxiCompany,\ Location)
+comment0.text=\n\ Constructor\ for\ objects\ of\ class\ Shuttle\n\ @param\ company\ The\ taxi\ company.\ Must\ not\ be\ null.\n\ @param\ location\ The\ vehicle's\ starting\ point.\ Must\ not\ be\ null.\n\ @throws\ NullPointerException\ If\ company\ or\ location\ is\ null.\n
+comment1.params=
+comment1.target=boolean\ isFree()
+comment1.text=\n\ Is\ the\ shuttle\ free?\n\ @return\ Whether\ or\ not\ this\ vehicle\ is\ free.\n
+comment2.params=location
+comment2.target=void\ setPickupLocation(Location)
+comment2.text=\n\ Receive\ a\ pickup\ location.\n\ @param\ location\ The\ pickup\ location.\n
+comment3.params=passenger
+comment3.target=void\ pickup(Passenger)
+comment3.text=\n\ Receive\ a\ passenger.\n\ Add\ their\ destination\ to\ the\ list.\n\ @param\ passenger\ The\ passenger\ being\ picked\ up.\n
+comment4.params=
+comment4.target=void\ chooseTargetLocation()
+comment4.text=\n\ Decide\ where\ to\ go\ next,\ based\ on\ the\ list\ of\n\ possible\ destinations.\n
+comment5.params=
+comment5.target=void\ offloadPassenger()
+comment5.text=\n\ Offload\ a\ passenger\ whose\ destination\ is\ the\n\ current\ location.\n
+numComments=6

Semester 1/Programming 1/Java/examples/projects/chapter16/taxi-company-outline-testing/Shuttle.java

@@ -0,0 +1,76 @@
+import java.util.List;
+import java.util.LinkedList;
+    
+/**
+ * A shuttle is able to carry multiple passengers.
+ * 
+ * @author David J. Barnes and Michael Kölling
+ * @version 2016.02.29
+ */
+public class Shuttle extends Vehicle
+{
+    // The list of destinations for the shuttle.
+    private List<Location> destinations;
+    // The list of passengers on the shuttle.
+    private List<Passenger> passengers;
+
+    /**
+     * Constructor for objects of class Shuttle
+     * @param company The taxi company. Must not be null.
+     * @param location The vehicle's starting point. Must not be null.
+     * @throws NullPointerException If company or location is null.
+     */
+    public Shuttle(TaxiCompany company, Location location)
+    {
+        super(company, location);
+        destinations = new LinkedList<>();
+        passengers = new LinkedList<>();
+    }
+
+    /**
+     * Is the shuttle free?
+     * @return Whether or not this vehicle is free.
+     */
+    public boolean isFree()
+    {
+        return true;
+    }
+    
+    /**
+     * Receive a pickup location.
+     * @param location The pickup location.
+     */
+    public void setPickupLocation(Location location)
+    {
+        destinations.add(location);
+        chooseTargetLocation();
+    }
+    
+    /**
+     * Receive a passenger.
+     * Add their destination to the list.
+     * @param passenger The passenger being picked up.
+     */
+    public void pickup(Passenger passenger)
+    {
+        passengers.add(passenger);
+        destinations.add(passenger.getDestination());
+        chooseTargetLocation();
+    }
+
+    /**
+     * Decide where to go next, based on the list of
+     * possible destinations.
+     */
+    private void chooseTargetLocation()
+    {
+    }
+
+    /**
+     * Offload a passenger whose destination is the
+     * current location.
+     */
+    public void offloadPassenger()
+    {
+    }
+}

Semester 1/Programming 1/Java/examples/projects/chapter16/taxi-company-outline-testing/Taxi.ctxt

@@ -0,0 +1,17 @@
+#BlueJ class context
+comment0.params=company\ location
+comment0.target=Taxi(TaxiCompany,\ Location)
+comment0.text=\n\ Constructor\ for\ objects\ of\ class\ Taxi\n\ @param\ company\ The\ taxi\ company.\ Must\ not\ be\ null.\n\ @param\ location\ The\ vehicle's\ starting\ point.\ Must\ not\ be\ null.\n\ @throws\ NullPointerException\ If\ company\ or\ location\ is\ null.\n
+comment1.params=
+comment1.target=boolean\ isFree()
+comment1.text=\n\ Is\ the\ taxi\ free?\n\ @return\ Whether\ or\ not\ this\ taxi\ is\ free.\n
+comment2.params=location
+comment2.target=void\ setPickupLocation(Location)
+comment2.text=\n\ Receive\ a\ pickup\ location.\ This\ becomes\ the\n\ target\ location.\n\ @param\ location\ The\ pickup\ location.\n
+comment3.params=passenger
+comment3.target=void\ pickup(Passenger)
+comment3.text=\n\ Receive\ a\ passenger.\n\ Set\ their\ destination\ as\ the\ target\ location.\n\ @param\ passenger\ The\ passenger.\n
+comment4.params=
+comment4.target=void\ offloadPassenger()
+comment4.text=\n\ Offload\ the\ passenger.\n
+numComments=5

Semester 1/Programming 1/Java/examples/projects/chapter16/taxi-company-outline-testing/Taxi.java

@@ -0,0 +1,57 @@
+
+/**
+ * A taxi is able to carry a single passenger.
+ * 
+ * @author David J. Barnes and Michael Kölling
+ * @version 2016.02.29
+ */
+public class Taxi extends Vehicle
+{
+    /**
+     * Constructor for objects of class Taxi
+     * @param company The taxi company. Must not be null.
+     * @param location The vehicle's starting point. Must not be null.
+     * @throws NullPointerException If company or location is null.
+     */
+    public Taxi(TaxiCompany company, Location location)
+    {
+        super(company, location);
+    }
+
+    /**
+     * Is the taxi free?
+     * @return Whether or not this taxi is free.
+     */
+    public boolean isFree()
+    {
+        return getTargetLocation() == null;
+    }
+    
+    /**
+     * Receive a pickup location. This becomes the
+     * target location.
+     * @param location The pickup location.
+     */
+    public void setPickupLocation(Location location)
+    {
+        setTargetLocation(location);
+    }
+    
+    /**
+     * Receive a passenger.
+     * Set their destination as the target location.
+     * @param passenger The passenger.
+     */
+    public void pickup(Passenger passenger)
+    {
+        setTargetLocation(passenger.getDestination());
+    }
+
+    /**
+     * Offload the passenger.
+     */
+    public void offloadPassenger()
+    {
+        clearTargetLocation();
+    }
+}

Semester 1/Programming 1/Java/examples/projects/chapter16/taxi-company-outline-testing/TaxiCompany.ctxt

@@ -0,0 +1,17 @@
+#BlueJ class context
+comment0.params=
+comment0.target=TaxiCompany()
+comment0.text=\n\ Constructor\ for\ objects\ of\ class\ TaxiCompany\n
+comment1.params=passenger
+comment1.target=boolean\ requestPickup(Passenger)
+comment1.text=\n\ Request\ a\ pickup\ for\ the\ given\ passenger.\n\ @param\ passenger\ The\ passenger\ requesting\ a\ pickup.\n\ @return\ Whether\ a\ free\ vehicle\ is\ available.\n
+comment2.params=vehicle
+comment2.target=void\ arrivedAtPickup(Vehicle)
+comment2.text=\n\ A\ vehicle\ has\ arrived\ at\ a\ pickup\ point.\n\ @param\ vehicle\ The\ vehicle\ at\ the\ pickup\ point.\n
+comment3.params=vehicle\ passenger
+comment3.target=void\ arrivedAtDestination(Vehicle,\ Passenger)
+comment3.text=\n\ A\ vehicle\ has\ arrived\ at\ a\ passenger's\ destination.\n\ @param\ vehicle\ The\ vehicle\ at\ the\ destination.\n\ @param\ passenger\ The\ passenger\ being\ dropped\ off.\n
+comment4.params=
+comment4.target=Vehicle\ scheduleVehicle()
+comment4.text=\n\ Find\ a\ free\ vehicle,\ if\ any.\n\ @return\ A\ free\ vehicle,\ or\ null\ if\ there\ is\ none.\n
+numComments=5

Semester 1/Programming 1/Java/examples/projects/chapter16/taxi-company-outline-testing/TaxiCompany.java

@@ -0,0 +1,74 @@
+import java.util.Iterator;
+import java.util.List;
+import java.util.LinkedList;
+
+/**
+ * Model the operation of a taxi company, operating different
+ * types of vehicle.
+ * 
+ * @author David J. Barnes and Michael Kölling
+ * @version 2016.02.29
+ */
+public class TaxiCompany  
+{
+    private List<Vehicle> vehicles;
+
+    /**
+     * Constructor for objects of class TaxiCompany
+     */
+    public TaxiCompany()
+    {
+        vehicles = new LinkedList<>();
+    }
+
+    /**
+     * Request a pickup for the given passenger.
+     * @param passenger The passenger requesting a pickup.
+     * @return Whether a free vehicle is available.
+     */
+    public boolean requestPickup(Passenger passenger)
+    {
+        Vehicle vehicle = scheduleVehicle();
+        if(vehicle != null) {
+            vehicle.setPickupLocation(passenger.getPickupLocation());
+            return true;
+        }
+        else {
+            return false;
+        }
+    }
+    
+    /**
+     * A vehicle has arrived at a pickup point.
+     * @param vehicle The vehicle at the pickup point.
+     */
+    public void arrivedAtPickup(Vehicle vehicle)
+    {
+    }
+    
+    /**
+     * A vehicle has arrived at a passenger's destination.
+     * @param vehicle The vehicle at the destination.
+     * @param passenger The passenger being dropped off.
+     */
+    public void arrivedAtDestination(Vehicle vehicle,
+                                     Passenger passenger)
+    {
+    }
+    
+    /**
+     * Find a free vehicle, if any.
+     * @return A free vehicle, or null if there is none.
+     */
+    private Vehicle scheduleVehicle()
+    {
+        Iterator<Vehicle> it = vehicles.iterator();
+        while(it.hasNext()) {
+            Vehicle vehicle = it.next();
+            if(vehicle.isFree()) {
+                return vehicle;
+            }
+        }
+        return null;
+    }
+}

Semester 1/Programming 1/Java/examples/projects/chapter16/taxi-company-outline-testing/TaxiTest.ctxt

@@ -0,0 +1,20 @@
+#BlueJ class context
+comment0.params=
+comment0.target=TaxiTest()
+comment0.text=\n\ Default\ constructor\ for\ test\ class\ TaxiTest\n
+comment1.params=
+comment1.target=void\ setUp()
+comment1.text=\n\ Create\ a\ taxi.\n\n\ Called\ before\ every\ test\ case\ method.\n
+comment2.params=
+comment2.target=void\ tearDown()
+comment2.text=\n\ Tears\ down\ the\ test\ fixture.\n\n\ Called\ after\ every\ test\ case\ method.\n
+comment3.params=
+comment3.target=void\ testCreation()
+comment3.text=\n\ Test\ creation\ and\ the\ initial\ state\ of\ a\ taxi.\n
+comment4.params=
+comment4.target=void\ testPickup()
+comment4.text=\n\ Test\ that\ a\ taxi\ is\ no\ longer\ free\ after\ it\ has\n\ picked\ up\ a\ passenger.\n
+comment5.params=
+comment5.target=void\ testOffload()
+comment5.text=\n\ Test\ that\ a\ taxi\ becomes\ free\ again\ after\ offloading\n\ a\ passenger.\n
+numComments=6

Semester 1/Programming 1/Java/examples/projects/chapter16/taxi-company-outline-testing/TaxiTest.java

@@ -0,0 +1,81 @@
+import static org.junit.Assert.*;
+import org.junit.After;
+import org.junit.Before;
+import org.junit.Test;
+
+/**
+ * The test class TaxiTest.
+ *
+ * @author  (your name)
+ * @version (a version number or a date)
+ */
+public class TaxiTest
+{
+    private Taxi taxi;
+    
+    /**
+     * Default constructor for test class TaxiTest
+     */
+    public TaxiTest()
+    {
+    }
+
+    /**
+     * Create a taxi.
+     *
+     * Called before every test case method.
+     */
+    @Before
+    public void setUp()
+    {
+        TaxiCompany company = new TaxiCompany();
+        Location taxiLocation = new Location();
+        taxi = new Taxi(company, taxiLocation);
+    }
+
+    /**
+     * Tears down the test fixture.
+     *
+     * Called after every test case method.
+     */
+    @After
+    public void tearDown()
+    {
+    }
+    
+    /**
+     * Test creation and the initial state of a taxi.
+     */
+    @Test
+    public void testCreation()
+    {
+        assertEquals(true, taxi.isFree());
+    }
+    
+    /**
+     * Test that a taxi is no longer free after it has
+     * picked up a passenger.
+     */
+    @Test
+    public void testPickup()
+    {
+        Location pickup = new Location();
+        Location destination = new Location();
+        Passenger passenger = new Passenger(pickup, destination);
+        taxi.pickup(passenger);
+        assertEquals(false, taxi.isFree());
+    }
+    
+    /**
+     * Test that a taxi becomes free again after offloading
+     * a passenger.
+     */
+    @Test
+    public void testOffload()
+    {
+        testPickup();
+        taxi.offloadPassenger();
+        assertEquals(true, taxi.isFree());
+    }
+}
+

Semester 1/Programming 1/Java/examples/projects/chapter16/taxi-company-outline-testing/Vehicle.ctxt

@@ -0,0 +1,38 @@
+#BlueJ class context
+comment0.params=company\ location
+comment0.target=Vehicle(TaxiCompany,\ Location)
+comment0.text=\n\ Constructor\ of\ class\ Vehicle\n\ @param\ company\ The\ taxi\ company.\ Must\ not\ be\ null.\n\ @param\ location\ The\ vehicle's\ starting\ point.\ Must\ not\ be\ null.\n\ @throws\ NullPointerException\ If\ company\ or\ location\ is\ null.\n
+comment1.params=
+comment1.target=void\ notifyPickupArrival()
+comment1.text=\n\ Notify\ the\ company\ of\ our\ arrival\ at\ a\ pickup\ location.\n
+comment10.params=location
+comment10.target=void\ setTargetLocation(Location)
+comment10.text=\n\ Set\ the\ required\ target\ location.\n\ @param\ location\ Where\ to\ go.\ Must\ not\ be\ null.\n\ @throws\ NullPointerException\ If\ location\ is\ null.\n
+comment11.params=
+comment11.target=void\ clearTargetLocation()
+comment11.text=\n\ Clear\ the\ target\ location.\n
+comment2.params=passenger
+comment2.target=void\ notifyPassengerArrival(Passenger)
+comment2.text=\n\ Notify\ the\ company\ of\ our\ arrival\ at\ a\n\ passenger's\ destination.\n\ @param\ passenger\ The\ passenger\ who\ has\ arrived.\n
+comment3.params=location
+comment3.target=void\ setPickupLocation(Location)
+comment3.text=\n\ Receive\ a\ pickup\ location.\n\ How\ this\ is\ handled\ depends\ on\ the\ type\ of\ vehicle.\n\ @param\ location\ The\ pickup\ location.\n
+comment4.params=passenger
+comment4.target=void\ pickup(Passenger)
+comment4.text=\n\ Receive\ a\ passenger.\n\ How\ this\ is\ handled\ depends\ on\ the\ type\ of\ vehicle.\n\ @param\ passenger\ The\ passenger\ being\ picked\ up.\n
+comment5.params=
+comment5.target=boolean\ isFree()
+comment5.text=\n\ @return\ Whether\ or\ not\ this\ vehicle\ is\ free.\n
+comment6.params=
+comment6.target=void\ offloadPassenger()
+comment6.text=\n\ Offload\ any\ passengers\ whose\ destination\ is\ the\n\ current\ location.\n
+comment7.params=
+comment7.target=Location\ getLocation()
+comment7.text=\n\ Get\ the\ location.\n\ @return\ Where\ this\ vehicle\ is\ currently\ located.\n
+comment8.params=location
+comment8.target=void\ setLocation(Location)
+comment8.text=\n\ Set\ the\ current\ location.\n\ @param\ location\ Where\ it\ is.\ Must\ not\ be\ null.\n\ @throws\ NullPointerException\ If\ location\ is\ null.\n
+comment9.params=
+comment9.target=Location\ getTargetLocation()
+comment9.text=\n\ Get\ the\ target\ location.\n\ @return\ Where\ this\ vehicle\ is\ currently\ headed,\ or\ null\n\ \ \ \ \ \ \ \ \ if\ it\ is\ idle.\n
+numComments=12

Semester 1/Programming 1/Java/examples/projects/chapter16/taxi-company-outline-testing/Vehicle.java

@@ -0,0 +1,133 @@
+/**
+ * Capture outline details of a vehicle.
+ * 
+ * @author David J. Barnes and Michael Kölling
+ * @version 2016.02.29
+ */
+public abstract class Vehicle
+{
+    private TaxiCompany company;
+    // Where the vehicle is.
+    private Location location;
+    // Where the vehicle is headed.
+    private Location targetLocation;
+    
+    /**
+     * Constructor of class Vehicle
+     * @param company The taxi company. Must not be null.
+     * @param location The vehicle's starting point. Must not be null.
+     * @throws NullPointerException If company or location is null.
+     */
+    public Vehicle(TaxiCompany company, Location location)
+    {
+        if(company == null) {
+            throw new NullPointerException("company");
+        }
+        if(location == null) {
+            throw new NullPointerException("location");
+        }
+        this.company = company;
+        this.location = location;
+        targetLocation = null;
+    }
+    
+    /**
+     * Notify the company of our arrival at a pickup location.
+     */
+    public void notifyPickupArrival()
+    {
+        company.arrivedAtPickup(this);
+    }
+    
+    /**
+     * Notify the company of our arrival at a
+     * passenger's destination.
+     * @param passenger The passenger who has arrived.
+     */
+    public void notifyPassengerArrival(Passenger passenger)
+    {
+        company.arrivedAtDestination(this, passenger);
+    }
+    
+    /**
+     * Receive a pickup location.
+     * How this is handled depends on the type of vehicle.
+     * @param location The pickup location.
+     */
+    public abstract void setPickupLocation(Location location);
+    
+    /**
+     * Receive a passenger.
+     * How this is handled depends on the type of vehicle.
+     * @param passenger The passenger being picked up.
+     */
+    public abstract void pickup(Passenger passenger);
+    
+    /**
+     * @return Whether or not this vehicle is free.
+     */
+    public abstract boolean isFree();
+    
+    /**
+     * Offload any passengers whose destination is the
+     * current location.
+     */
+    public abstract void offloadPassenger();
+    
+    /**
+     * Get the location.
+     * @return Where this vehicle is currently located.
+     */
+    public Location getLocation()
+    {
+        return location;
+    }
+    
+    /**
+     * Set the current location.
+     * @param location Where it is. Must not be null.
+     * @throws NullPointerException If location is null.
+     */
+    public void setLocation(Location location)
+    {
+        if(location != null) {
+            this.location = location;
+        }
+        else {
+            throw new NullPointerException();
+        }
+    }
+    
+    /**
+     * Get the target location.
+     * @return Where this vehicle is currently headed, or null
+     *         if it is idle.
+     */
+    public Location getTargetLocation()
+    {
+        return targetLocation;
+    }
+    
+    /**
+     * Set the required target location.
+     * @param location Where to go. Must not be null.
+     * @throws NullPointerException If location is null.
+     */
+    public void setTargetLocation(Location location)
+    {
+        if(location != null) {
+            targetLocation = location;
+        }
+        else {
+            throw new NullPointerException();
+        }
+    }
+    
+    /**
+     * Clear the target location.
+     */
+    public void clearTargetLocation()
+    {
+        targetLocation = null;
+    }
+}

Semester 1/Programming 1/Java/examples/projects/chapter16/taxi-company-outline-testing/package.bluej

@@ -0,0 +1,224 @@
+#BlueJ package file
+dependency1.from=PassengerSourceTest
+dependency1.to=TaxiCompany
+dependency1.type=UsesDependency
+dependency10.from=TaxiTest
+dependency10.to=Passenger
+dependency10.type=UsesDependency
+dependency11.from=TaxiCompany
+dependency11.to=Passenger
+dependency11.type=UsesDependency
+dependency12.from=TaxiCompany
+dependency12.to=Vehicle
+dependency12.type=UsesDependency
+dependency13.from=Passenger
+dependency13.to=Location
+dependency13.type=UsesDependency
+dependency14.from=PassengerSource
+dependency14.to=TaxiCompany
+dependency14.type=UsesDependency
+dependency15.from=PassengerSource
+dependency15.to=Passenger
+dependency15.type=UsesDependency
+dependency16.from=PassengerSource
+dependency16.to=Location
+dependency16.type=UsesDependency
+dependency17.from=PassengerTest
+dependency17.to=Location
+dependency17.type=UsesDependency
+dependency18.from=Vehicle
+dependency18.to=TaxiCompany
+dependency18.type=UsesDependency
+dependency19.from=Vehicle
+dependency19.to=Location
+dependency19.type=UsesDependency
+dependency2.from=Taxi
+dependency2.to=TaxiCompany
+dependency2.type=UsesDependency
+dependency20.from=Vehicle
+dependency20.to=Passenger
+dependency20.type=UsesDependency
+dependency21.from=TaxiCompany
+dependency21.to=Taxi
+dependency21.type=UsesDependency
+dependency22.from=TaxiCompany
+dependency22.to=Location
+dependency22.type=UsesDependency
+dependency23.from=PassengerSourceTest
+dependency23.to=PassengerSource
+dependency23.type=UsesDependency
+dependency24.from=TaxiTest
+dependency24.to=Taxi
+dependency24.type=UsesDependency
+dependency25.from=PassengerTest
+dependency25.to=Passenger
+dependency25.type=UsesDependency
+dependency3.from=Taxi
+dependency3.to=Location
+dependency3.type=UsesDependency
+dependency4.from=Taxi
+dependency4.to=Passenger
+dependency4.type=UsesDependency
+dependency5.from=Shuttle
+dependency5.to=TaxiCompany
+dependency5.type=UsesDependency
+dependency6.from=Shuttle
+dependency6.to=Location
+dependency6.type=UsesDependency
+dependency7.from=Shuttle
+dependency7.to=Passenger
+dependency7.type=UsesDependency
+dependency8.from=TaxiTest
+dependency8.to=TaxiCompany
+dependency8.type=UsesDependency
+dependency9.from=TaxiTest
+dependency9.to=Location
+dependency9.type=UsesDependency
+objectbench.height=76
+objectbench.width=806
+package.editor.height=548
+package.editor.width=698
+package.editor.x=70
+package.editor.y=80
+package.numDependencies=25
+package.numTargets=10
+package.showExtends=true
+package.showUses=true
+project.charset=UTF-8
+readme.editor.height=571
+readme.editor.width=770
+readme.editor.x=53
+readme.editor.y=23
+target1.editor.height=700
+target1.editor.width=900
+target1.editor.x=53
+target1.editor.y=23
+target1.height=50
+target1.name=Vehicle
+target1.naviview.expanded=true
+target1.showInterface=false
+target1.type=AbstractTarget
+target1.typeParameters=
+target1.width=80
+target1.x=490
+target1.y=100
+target10.editor.height=730
+target10.editor.width=748
+target10.editor.x=53
+target10.editor.y=60
+target10.height=50
+target10.name=Location
+target10.naviview.expanded=true
+target10.showInterface=false
+target10.type=ClassTarget
+target10.typeParameters=
+target10.width=80
+target10.x=110
+target10.y=430
+target2.editor.height=700
+target2.editor.width=900
+target2.editor.x=53
+target2.editor.y=23
+target2.height=50
+target2.name=TaxiCompany
+target2.naviview.expanded=true
+target2.showInterface=false
+target2.type=ClassTarget
+target2.typeParameters=
+target2.width=100
+target2.x=190
+target2.y=30
+target3.editor.height=735
+target3.editor.width=784
+target3.editor.x=117
+target3.editor.y=75
+target3.height=50
+target3.name=TaxiTest
+target3.naviview.expanded=true
+target3.showInterface=false
+target3.type=UnitTestTargetJunit4
+target3.typeParameters=
+target3.width=80
+target3.x=430
+target3.y=200
+target4.editor.height=720
+target4.editor.width=842
+target4.editor.x=53
+target4.editor.y=63
+target4.height=50
+target4.name=PassengerSourceTest
+target4.naviview.expanded=true
+target4.showInterface=false
+target4.type=UnitTestTargetJunit4
+target4.typeParameters=
+target4.width=150
+target4.x=50
+target4.y=100
+target5.association=TaxiTest
+target5.editor.height=700
+target5.editor.width=900
+target5.editor.x=53
+target5.editor.y=23
+target5.height=50
+target5.name=Taxi
+target5.naviview.expanded=true
+target5.showInterface=false
+target5.type=ClassTarget
+target5.typeParameters=
+target5.width=80
+target5.x=400
+target5.y=230
+target6.editor.height=726
+target6.editor.width=907
+target6.editor.x=158
+target6.editor.y=83
+target6.height=50
+target6.name=PassengerTest
+target6.naviview.expanded=true
+target6.showInterface=false
+target6.type=UnitTestTargetJunit4
+target6.typeParameters=
+target6.width=110
+target6.x=300
+target6.y=310
+target7.association=PassengerTest
+target7.editor.height=700
+target7.editor.width=900
+target7.editor.x=53
+target7.editor.y=23
+target7.height=50
+target7.name=Passenger
+target7.naviview.expanded=true
+target7.showInterface=false
+target7.type=ClassTarget
+target7.typeParameters=
+target7.width=90
+target7.x=270
+target7.y=340
+target8.association=PassengerSourceTest
+target8.editor.height=700
+target8.editor.width=900
+target8.editor.x=53
+target8.editor.y=23
+target8.height=50
+target8.name=PassengerSource
+target8.naviview.expanded=true
+target8.showInterface=false
+target8.type=ClassTarget
+target8.typeParameters=
+target8.width=130
+target8.x=20
+target8.y=130
+target9.editor.height=707
+target9.editor.width=811
+target9.editor.x=53
+target9.editor.y=60
+target9.height=50
+target9.name=Shuttle
+target9.naviview.expanded=false
+target9.showInterface=false
+target9.type=ClassTarget
+target9.typeParameters=
+target9.width=80
+target9.x=570
+target9.y=190

Semester 1/Programming 1/Java/examples/projects/chapter16/taxi-company-outline/Demo.ctxt

@@ -0,0 +1,8 @@
+#BlueJ class context
+comment0.params=
+comment0.target=Demo()
+comment0.text=\n\ Create\ some\ sample\ objects\ for\ the\ demo.\n
+comment1.params=
+comment1.target=void\ pickupTest()
+comment1.text=\n\ Request\ a\ pickup\ for\ a\ new\ passenger.\n\ The\ request\ will\ fail\ in\ this\ version.\n
+numComments=2

Semester 1/Programming 1/Java/examples/projects/chapter16/taxi-company-outline/Demo.java

@@ -0,0 +1,35 @@
+/**
+ * Set up a passenger-source and taxi-company, to illustrate
+ * the scenario of requesting a pickup.
+ * 
+ * @author David J. Barnes and Michael Kölling
+ * @version 2016.02.29
+ */
+public class Demo
+{
+    private PassengerSource source;
+    private TaxiCompany company;
+
+    /**
+     * Create some sample objects for the demo.
+     */
+    public Demo()
+    {
+        company = new TaxiCompany();
+        source = new PassengerSource(company);
+    }
+
+    /**
+     * Request a pickup for a new passenger.
+     * The request will fail in this version.
+     */
+    public void pickupTest()
+    {
+        if(source.requestPickup()) {
+            System.out.println("Pickup request succeeded.");
+        }
+        else {
+            System.out.println("Pickup request failed.");
+        }
+    }
+}

Semester 1/Programming 1/Java/examples/projects/chapter16/taxi-company-outline/Location.ctxt

@@ -0,0 +1,5 @@
+#BlueJ class context
+comment0.params=
+comment0.target=Location()
+comment0.text=\n\ Constructor\ for\ objects\ of\ class\ Location\n
+numComments=1

Semester 1/Programming 1/Java/examples/projects/chapter16/taxi-company-outline/Location.java

@@ -0,0 +1,15 @@
+/**
+ * Model a location in a city.
+ * 
+ * @author David J. Barnes and Michael Kölling
+ * @version 2016.02.29
+ */
+public class Location
+{
+    /**
+     * Constructor for objects of class Location
+     */
+    public Location()
+    {
+    }
+}

Semester 1/Programming 1/Java/examples/projects/chapter16/taxi-company-outline/Passenger.ctxt

@@ -0,0 +1,11 @@
+#BlueJ class context
+comment0.params=pickup\ destination
+comment0.target=Passenger(Location,\ Location)
+comment0.text=\n\ Constructor\ for\ objects\ of\ class\ Passenger\n\ @param\ pickup\ The\ pickup\ location,\ must\ not\ be\ null.\n\ @param\ destination\ The\ destination\ location,\ must\ not\ be\ null.\n\ @throws\ NullPointerException\ If\ either\ location\ is\ null.\n
+comment1.params=
+comment1.target=Location\ getPickupLocation()
+comment1.text=\n\ @return\ The\ pickup\ location.\n
+comment2.params=
+comment2.target=Location\ getDestination()
+comment2.text=\n\ @return\ The\ destination\ location.\n
+numComments=3

Semester 1/Programming 1/Java/examples/projects/chapter16/taxi-company-outline/Passenger.java

@@ -0,0 +1,46 @@
+/**
+ * Model a passenger wishing to get from one
+ * location to another.
+ * 
+ * @author David J. Barnes and Michael Kölling
+ * @version 2016.02.29
+ */
+public class Passenger
+{
+    private Location pickup;
+    private Location destination;
+
+    /**
+     * Constructor for objects of class Passenger
+     * @param pickup The pickup location, must not be null.
+     * @param destination The destination location, must not be null.
+     * @throws NullPointerException If either location is null.
+     */
+    public Passenger(Location pickup, Location destination)
+    {
+        if(pickup == null) {
+            throw new NullPointerException("Pickup location");
+        }
+        if(destination == null) {
+            throw new NullPointerException("Destination location");
+        }
+        this.pickup = pickup;
+        this.destination = destination;
+    }
+
+    /**
+     * @return The pickup location.
+     */
+    public Location getPickupLocation()
+    {
+        return pickup;
+    }
+    
+    /**
+     * @return The destination location.
+     */
+    public Location getDestination()
+    {
+        return destination;
+    }
+}

Semester 1/Programming 1/Java/examples/projects/chapter16/taxi-company-outline/PassengerSource.ctxt

@@ -0,0 +1,11 @@
+#BlueJ class context
+comment0.params=company
+comment0.target=PassengerSource(TaxiCompany)
+comment0.text=\n\ Constructor\ for\ objects\ of\ class\ PassengerSource.\n\ @param\ company\ The\ company\ to\ be\ used.\ Must\ not\ be\ null.\n\ @throws\ NullPointerException\ if\ company\ is\ null.\n
+comment1.params=
+comment1.target=boolean\ requestPickup()
+comment1.text=\n\ Have\ the\ source\ generate\ a\ new\ passenger\ and\n\ request\ a\ pickup\ from\ the\ company.\n\ @return\ true\ If\ the\ request\ succeeds,\ false\ otherwise.\n
+comment2.params=
+comment2.target=Passenger\ createPassenger()
+comment2.text=\n\ Create\ a\ new\ passenger.\n\ @return\ The\ created\ passenger.\n
+numComments=3

Semester 1/Programming 1/Java/examples/projects/chapter16/taxi-company-outline/PassengerSource.java

@@ -0,0 +1,44 @@
+/**
+ * Simulate passengers requesting rides from a taxi company.
+ * Passengers should be generated at random intervals.
+ * 
+ * @author David J. Barnes and Michael Kölling
+ * @version 2016.02.29
+ */
+public class PassengerSource
+{
+    private TaxiCompany company;
+
+    /**
+     * Constructor for objects of class PassengerSource.
+     * @param company The company to be used. Must not be null.
+     * @throws NullPointerException if company is null.
+     */
+    public PassengerSource(TaxiCompany company)
+    {
+        if(company == null) {
+            throw new NullPointerException("company");
+        }
+        this.company = company;
+    }
+
+    /**
+     * Have the source generate a new passenger and
+     * request a pickup from the company.
+     * @return true If the request succeeds, false otherwise.
+     */
+    public boolean requestPickup()
+    {
+        Passenger passenger = createPassenger();
+        return company.requestPickup(passenger);
+    }
+
+    /**
+     * Create a new passenger.
+     * @return The created passenger.
+     */
+    private Passenger createPassenger()
+    {
+        return new Passenger(new Location(), new Location());
+    }
+}

Semester 1/Programming 1/Java/examples/projects/chapter16/taxi-company-outline/README.TXT

@@ -0,0 +1,26 @@
+Project: taxi-company-outline
+Authors: David J. Barnes and Michael Kölling
+
+This project is part of the material for chapter 14 of the book
+
+   Objects First with Java - A Practical Introduction using BlueJ
+   Sixth edition
+   David J. Barnes and Michael Kölling
+   Pearson Education, 2016
+
+This project provides a partial implementation of a simulation of
+taxis operating on a city grid to pick up and transport passengers.
+    
+This is the first stage of this project. It illustrates an outline 
+implementation form derived from CRC interaction.
+
+How to start this project:
+    Create a TaxiCompany and a PassengerSource. Call the requestPickup
+    method of the source. However, as there are no vehicles created,
+    no passengers will ever be picked up. (This functionality is also
+    capture in the Demo class.)
+
+    Create at least one Taxi in the constructor of TaxiCompany and
+    add it to the vehicles collection. Then a passenger will have
+    a taxi scheduled to pick them up. However, as vehicles do not
+    yet move, they never will be picked up.

Semester 1/Programming 1/Java/examples/projects/chapter16/taxi-company-outline/Shuttle.ctxt

@@ -0,0 +1,20 @@
+#BlueJ class context
+comment0.params=company\ location
+comment0.target=Shuttle(TaxiCompany,\ Location)
+comment0.text=\n\ Constructor\ for\ objects\ of\ class\ Shuttle\n\ @param\ company\ The\ taxi\ company.\ Must\ not\ be\ null.\n\ @param\ location\ The\ vehicle's\ starting\ point.\ Must\ not\ be\ null.\n\ @throws\ NullPointerException\ If\ company\ or\ location\ is\ null.\n
+comment1.params=
+comment1.target=boolean\ isFree()
+comment1.text=\n\ Is\ the\ shuttle\ free?\n\ @return\ Whether\ or\ not\ this\ vehicle\ is\ free.\n
+comment2.params=location
+comment2.target=void\ setPickupLocation(Location)
+comment2.text=\n\ Receive\ a\ pickup\ location.\n\ @param\ location\ The\ pickup\ location.\n
+comment3.params=passenger
+comment3.target=void\ pickup(Passenger)
+comment3.text=\n\ Receive\ a\ passenger.\n\ Add\ their\ destination\ to\ the\ list.\n\ @param\ passenger\ The\ passenger\ being\ picked\ up.\n
+comment4.params=
+comment4.target=void\ chooseTargetLocation()
+comment4.text=\n\ Decide\ where\ to\ go\ next,\ based\ on\ the\ list\ of\n\ possible\ destinations.\n
+comment5.params=
+comment5.target=void\ offloadPassenger()
+comment5.text=\n\ Offload\ a\ passenger\ whose\ destination\ is\ the\n\ current\ location.\n
+numComments=6

Semester 1/Programming 1/Java/examples/projects/chapter16/taxi-company-outline/Shuttle.java

@@ -0,0 +1,76 @@
+import java.util.List;
+import java.util.LinkedList;
+    
+/**
+ * A shuttle is able to carry multiple passengers.
+ * 
+ * @author David J. Barnes and Michael Kölling
+ * @version 2016.02.29
+ */
+public class Shuttle extends Vehicle
+{
+    // The list of destinations for the shuttle.
+    private List<Location> destinations;
+    // The list of passengers on the shuttle.
+    private List<Passenger> passengers;
+
+    /**
+     * Constructor for objects of class Shuttle
+     * @param company The taxi company. Must not be null.
+     * @param location The vehicle's starting point. Must not be null.
+     * @throws NullPointerException If company or location is null.
+     */
+    public Shuttle(TaxiCompany company, Location location)
+    {
+        super(company, location);
+        destinations = new LinkedList<>();
+        passengers = new LinkedList<>();
+    }
+
+    /**
+     * Is the shuttle free?
+     * @return Whether or not this vehicle is free.
+     */
+    public boolean isFree()
+    {
+        return true;
+    }
+    
+    /**
+     * Receive a pickup location.
+     * @param location The pickup location.
+     */
+    public void setPickupLocation(Location location)
+    {
+        destinations.add(location);
+        chooseTargetLocation();
+    }
+    
+    /**
+     * Receive a passenger.
+     * Add their destination to the list.
+     * @param passenger The passenger being picked up.
+     */
+    public void pickup(Passenger passenger)
+    {
+        passengers.add(passenger);
+        destinations.add(passenger.getDestination());
+        chooseTargetLocation();
+    }
+
+    /**
+     * Decide where to go next, based on the list of
+     * possible destinations.
+     */
+    private void chooseTargetLocation()
+    {
+    }
+
+    /**
+     * Offload a passenger whose destination is the
+     * current location.
+     */
+    public void offloadPassenger()
+    {
+    }
+}

Semester 1/Programming 1/Java/examples/projects/chapter16/taxi-company-outline/Taxi.ctxt

@@ -0,0 +1,17 @@
+#BlueJ class context
+comment0.params=company\ location
+comment0.target=Taxi(TaxiCompany,\ Location)
+comment0.text=\n\ Constructor\ for\ objects\ of\ class\ Taxi\n\ @param\ company\ The\ taxi\ company.\ Must\ not\ be\ null.\n\ @param\ location\ The\ vehicle's\ starting\ point.\n\ Must\ not\ be\ null.\n\ @throws\ NullPointerException\ If\ company\ or\ location\ is\ null.\n
+comment1.params=
+comment1.target=boolean\ isFree()
+comment1.text=\n\ Is\ the\ taxi\ free?\n\ @return\ Whether\ or\ not\ this\ taxi\ is\ free.\n
+comment2.params=location
+comment2.target=void\ setPickupLocation(Location)
+comment2.text=\n\ Receive\ a\ pickup\ location.\ This\ becomes\ the\n\ target\ location.\n\ @param\ location\ The\ pickup\ location.\n
+comment3.params=passenger
+comment3.target=void\ pickup(Passenger)
+comment3.text=\n\ Receive\ a\ passenger.\n\ Set\ their\ destination\ as\ the\ target\ location.\n\ @param\ passenger\ The\ passenger.\n
+comment4.params=
+comment4.target=void\ offloadPassenger()
+comment4.text=\n\ Offload\ the\ passenger.\n
+numComments=5

Semester 1/Programming 1/Java/examples/projects/chapter16/taxi-company-outline/Taxi.java

@@ -0,0 +1,58 @@
+
+/**
+ * A taxi is able to carry a single passenger.
+ * 
+ * @author David J. Barnes and Michael Kölling
+ * @version 2016.02.29
+ */
+public class Taxi extends Vehicle
+{
+    /**
+     * Constructor for objects of class Taxi
+     * @param company The taxi company. Must not be null.
+     * @param location The vehicle's starting point.
+     * Must not be null.
+     * @throws NullPointerException If company or location is null.
+     */
+    public Taxi(TaxiCompany company, Location location)
+    {
+        super(company, location);
+    }
+
+    /**
+     * Is the taxi free?
+     * @return Whether or not this taxi is free.
+     */
+    public boolean isFree()
+    {
+        return getTargetLocation() == null;
+    }
+    
+    /**
+     * Receive a pickup location. This becomes the
+     * target location.
+     * @param location The pickup location.
+     */
+    public void setPickupLocation(Location location)
+    {
+        setTargetLocation(location);
+    }
+    
+    /**
+     * Receive a passenger.
+     * Set their destination as the target location.
+     * @param passenger The passenger.
+     */
+    public void pickup(Passenger passenger)
+    {
+        setTargetLocation(passenger.getDestination());
+    }
+
+    /**
+     * Offload the passenger.
+     */
+    public void offloadPassenger()
+    {
+        clearTargetLocation();
+    }
+}

Semester 1/Programming 1/Java/examples/projects/chapter16/taxi-company-outline/TaxiCompany.ctxt

@@ -0,0 +1,17 @@
+#BlueJ class context
+comment0.params=
+comment0.target=TaxiCompany()
+comment0.text=\n\ Constructor\ for\ objects\ of\ class\ TaxiCompany\n
+comment1.params=passenger
+comment1.target=boolean\ requestPickup(Passenger)
+comment1.text=\n\ Request\ a\ pickup\ for\ the\ given\ passenger.\n\ @param\ passenger\ The\ passenger\ requesting\ a\ pickup.\n\ @return\ Whether\ a\ free\ vehicle\ is\ available.\n
+comment2.params=vehicle
+comment2.target=void\ arrivedAtPickup(Vehicle)
+comment2.text=\n\ A\ vehicle\ has\ arrived\ at\ a\ pickup\ point.\n\ @param\ vehicle\ The\ vehicle\ at\ the\ pickup\ point.\n
+comment3.params=vehicle\ passenger
+comment3.target=void\ arrivedAtDestination(Vehicle,\ Passenger)
+comment3.text=\n\ A\ vehicle\ has\ arrived\ at\ a\ passenger's\ destination.\n\ @param\ vehicle\ The\ vehicle\ at\ the\ destination.\n\ @param\ passenger\ The\ passenger\ being\ dropped\ off.\n
+comment4.params=
+comment4.target=Vehicle\ scheduleVehicle()
+comment4.text=\n\ Find\ a\ free\ vehicle,\ if\ any.\n\ @return\ A\ free\ vehicle,\ or\ null\ if\ there\ is\ none.\n
+numComments=5

Semester 1/Programming 1/Java/examples/projects/chapter16/taxi-company-outline/TaxiCompany.java

@@ -0,0 +1,74 @@
+import java.util.Iterator;
+import java.util.List;
+import java.util.LinkedList;
+
+/**
+ * Model the operation of a taxi company, operating different
+ * types of vehicle.
+ * 
+ * @author David J. Barnes and Michael Kölling
+ * @version 2016.02.29
+ */
+public class TaxiCompany  
+{
+    private List<Vehicle> vehicles;
+
+    /**
+     * Constructor for objects of class TaxiCompany
+     */
+    public TaxiCompany()
+    {
+        vehicles = new LinkedList<>();
+    }
+
+    /**
+     * Request a pickup for the given passenger.
+     * @param passenger The passenger requesting a pickup.
+     * @return Whether a free vehicle is available.
+     */
+    public boolean requestPickup(Passenger passenger)
+    {
+        Vehicle vehicle = scheduleVehicle();
+        if(vehicle != null) {
+            vehicle.setPickupLocation(passenger.getPickupLocation());
+            return true;
+        }
+        else {
+            return false;
+        }
+    }
+    
+    /**
+     * A vehicle has arrived at a pickup point.
+     * @param vehicle The vehicle at the pickup point.
+     */
+    public void arrivedAtPickup(Vehicle vehicle)
+    {
+    }
+    
+    /**
+     * A vehicle has arrived at a passenger's destination.
+     * @param vehicle The vehicle at the destination.
+     * @param passenger The passenger being dropped off.
+     */
+    public void arrivedAtDestination(Vehicle vehicle,
+                                     Passenger passenger)
+    {
+    }
+    
+    /**
+     * Find a free vehicle, if any.
+     * @return A free vehicle, or null if there is none.
+     */
+    private Vehicle scheduleVehicle()
+    {
+        Iterator<Vehicle> it = vehicles.iterator();
+        while(it.hasNext()) {
+            Vehicle vehicle = it.next();
+            if(vehicle.isFree()) {
+                return vehicle;
+            }
+        }
+        return null;
+    }
+}

Semester 1/Programming 1/Java/examples/projects/chapter16/taxi-company-outline/Vehicle.ctxt

@@ -0,0 +1,38 @@
+#BlueJ class context
+comment0.params=company\ location
+comment0.target=Vehicle(TaxiCompany,\ Location)
+comment0.text=\n\ Constructor\ of\ class\ Vehicle\n\ @param\ company\ The\ taxi\ company.\ Must\ not\ be\ null.\n\ @param\ location\ The\ vehicle's\ starting\ point.\ Must\ not\ be\ null.\n\ @throws\ NullPointerException\ If\ company\ or\ location\ is\ null.\n
+comment1.params=
+comment1.target=void\ notifyPickupArrival()
+comment1.text=\n\ Notify\ the\ company\ of\ our\ arrival\ at\ a\ pickup\ location.\n
+comment10.params=location
+comment10.target=void\ setTargetLocation(Location)
+comment10.text=\n\ Set\ the\ required\ target\ location.\n\ @param\ location\ Where\ to\ go.\ Must\ not\ be\ null.\n\ @throws\ NullPointerException\ If\ location\ is\ null.\n
+comment11.params=
+comment11.target=void\ clearTargetLocation()
+comment11.text=\n\ Clear\ the\ target\ location.\n
+comment2.params=passenger
+comment2.target=void\ notifyPassengerArrival(Passenger)
+comment2.text=\n\ Notify\ the\ company\ of\ our\ arrival\ at\ a\n\ passenger's\ destination.\n\ @param\ passenger\ The\ passenger\ who\ has\ arrived.\n
+comment3.params=location
+comment3.target=void\ setPickupLocation(Location)
+comment3.text=\n\ Receive\ a\ pickup\ location.\n\ How\ this\ is\ handled\ depends\ on\ the\ type\ of\ vehicle.\n\ @param\ location\ The\ pickup\ location.\n
+comment4.params=passenger
+comment4.target=void\ pickup(Passenger)
+comment4.text=\n\ Receive\ a\ passenger.\n\ How\ this\ is\ handled\ depends\ on\ the\ type\ of\ vehicle.\n\ @param\ passenger\ The\ passenger\ being\ picked\ up.\n
+comment5.params=
+comment5.target=boolean\ isFree()
+comment5.text=\n\ Is\ the\ vehicle\ free?\n\ @return\ Whether\ or\ not\ this\ vehicle\ is\ free.\n
+comment6.params=
+comment6.target=void\ offloadPassenger()
+comment6.text=\n\ Offload\ any\ passengers\ whose\ destination\ is\ the\n\ current\ location.\n
+comment7.params=
+comment7.target=Location\ getLocation()
+comment7.text=\n\ Get\ the\ location.\n\ @return\ Where\ this\ vehicle\ is\ currently\ located.\n
+comment8.params=location
+comment8.target=void\ setLocation(Location)
+comment8.text=\n\ Set\ the\ current\ location.\n\ @param\ location\ Where\ it\ is.\ Must\ not\ be\ null.\n\ @throws\ NullPointerException\ If\ location\ is\ null.\n
+comment9.params=
+comment9.target=Location\ getTargetLocation()
+comment9.text=\n\ Get\ the\ target\ location.\n\ @return\ Where\ this\ vehicle\ is\ currently\ headed,\ or\ null\n\ \ \ \ \ \ \ \ \ if\ it\ is\ idle.\n
+numComments=12

Semester 1/Programming 1/Java/examples/projects/chapter16/taxi-company-outline/Vehicle.java

@@ -0,0 +1,134 @@
+/**
+ * Capture outline details of a vehicle.
+ * 
+ * @author David J. Barnes and Michael Kölling
+ * @version 2016.02.29
+ */
+public abstract class Vehicle
+{
+    private TaxiCompany company;
+    // Where the vehicle is.
+    private Location location;
+    // Where the vehicle is headed.
+    private Location targetLocation;
+    
+    /**
+     * Constructor of class Vehicle
+     * @param company The taxi company. Must not be null.
+     * @param location The vehicle's starting point. Must not be null.
+     * @throws NullPointerException If company or location is null.
+     */
+    public Vehicle(TaxiCompany company, Location location)
+    {
+        if(company == null) {
+            throw new NullPointerException("company");
+        }
+        if(location == null) {
+            throw new NullPointerException("location");
+        }
+        this.company = company;
+        this.location = location;
+        targetLocation = null;
+    }
+    
+    /**
+     * Notify the company of our arrival at a pickup location.
+     */
+    public void notifyPickupArrival()
+    {
+        company.arrivedAtPickup(this);
+    }
+    
+    /**
+     * Notify the company of our arrival at a
+     * passenger's destination.
+     * @param passenger The passenger who has arrived.
+     */
+    public void notifyPassengerArrival(Passenger passenger)
+    {
+        company.arrivedAtDestination(this, passenger);
+    }
+    
+    /**
+     * Receive a pickup location.
+     * How this is handled depends on the type of vehicle.
+     * @param location The pickup location.
+     */
+    public abstract void setPickupLocation(Location location);
+    
+    /**
+     * Receive a passenger.
+     * How this is handled depends on the type of vehicle.
+     * @param passenger The passenger being picked up.
+     */
+    public abstract void pickup(Passenger passenger);
+    
+    /**
+     * Is the vehicle free?
+     * @return Whether or not this vehicle is free.
+     */
+    public abstract boolean isFree();
+    
+    /**
+     * Offload any passengers whose destination is the
+     * current location.
+     */
+    public abstract void offloadPassenger();
+    
+    /**
+     * Get the location.
+     * @return Where this vehicle is currently located.
+     */
+    public Location getLocation()
+    {
+        return location;
+    }
+    
+    /**
+     * Set the current location.
+     * @param location Where it is. Must not be null.
+     * @throws NullPointerException If location is null.
+     */
+    public void setLocation(Location location)
+    {
+        if(location != null) {
+            this.location = location;
+        }
+        else {
+            throw new NullPointerException();
+        }
+    }
+    
+    /**
+     * Get the target location.
+     * @return Where this vehicle is currently headed, or null
+     *         if it is idle.
+     */
+    public Location getTargetLocation()
+    {
+        return targetLocation;
+    }
+    
+    /**
+     * Set the required target location.
+     * @param location Where to go. Must not be null.
+     * @throws NullPointerException If location is null.
+     */
+    public void setTargetLocation(Location location)
+    {
+        if(location != null) {
+            targetLocation = location;
+        }
+        else {
+            throw new NullPointerException();
+        }
+    }
+    
+    /**
+     * Clear the target location.
+     */
+    public void clearTargetLocation()
+    {
+        targetLocation = null;
+    }
+}

Semester 1/Programming 1/Java/examples/projects/chapter16/taxi-company-outline/package.bluej

@@ -0,0 +1,177 @@
+#BlueJ package file
+dependency1.from=Taxi
+dependency1.to=TaxiCompany
+dependency1.type=UsesDependency
+dependency10.from=TaxiCompany
+dependency10.to=Vehicle
+dependency10.type=UsesDependency
+dependency11.from=Passenger
+dependency11.to=Location
+dependency11.type=UsesDependency
+dependency12.from=PassengerSource
+dependency12.to=TaxiCompany
+dependency12.type=UsesDependency
+dependency13.from=PassengerSource
+dependency13.to=Passenger
+dependency13.type=UsesDependency
+dependency14.from=PassengerSource
+dependency14.to=Location
+dependency14.type=UsesDependency
+dependency15.from=Vehicle
+dependency15.to=TaxiCompany
+dependency15.type=UsesDependency
+dependency16.from=Vehicle
+dependency16.to=Location
+dependency16.type=UsesDependency
+dependency17.from=Vehicle
+dependency17.to=Passenger
+dependency17.type=UsesDependency
+dependency18.from=TaxiCompany
+dependency18.to=Taxi
+dependency18.type=UsesDependency
+dependency19.from=TaxiCompany
+dependency19.to=Location
+dependency19.type=UsesDependency
+dependency2.from=Taxi
+dependency2.to=Location
+dependency2.type=UsesDependency
+dependency3.from=Taxi
+dependency3.to=Passenger
+dependency3.type=UsesDependency
+dependency4.from=Shuttle
+dependency4.to=TaxiCompany
+dependency4.type=UsesDependency
+dependency5.from=Shuttle
+dependency5.to=Location
+dependency5.type=UsesDependency
+dependency6.from=Shuttle
+dependency6.to=Passenger
+dependency6.type=UsesDependency
+dependency7.from=Demo
+dependency7.to=PassengerSource
+dependency7.type=UsesDependency
+dependency8.from=Demo
+dependency8.to=TaxiCompany
+dependency8.type=UsesDependency
+dependency9.from=TaxiCompany
+dependency9.to=Passenger
+dependency9.type=UsesDependency
+objectbench.height=76
+objectbench.width=855
+package.editor.height=513
+package.editor.width=747
+package.editor.x=70
+package.editor.y=80
+package.numDependencies=19
+package.numTargets=8
+package.showExtends=true
+package.showUses=true
+project.charset=UTF-8
+readme.editor.height=587
+readme.editor.width=825
+readme.editor.x=53
+readme.editor.y=23
+target1.editor.height=739
+target1.editor.width=851
+target1.editor.x=53
+target1.editor.y=60
+target1.height=50
+target1.name=Vehicle
+target1.naviview.expanded=false
+target1.showInterface=false
+target1.type=AbstractTarget
+target1.typeParameters=
+target1.width=80
+target1.x=510
+target1.y=110
+target2.editor.height=738
+target2.editor.width=834
+target2.editor.x=53
+target2.editor.y=60
+target2.height=50
+target2.name=TaxiCompany
+target2.naviview.expanded=true
+target2.showInterface=false
+target2.type=ClassTarget
+target2.typeParameters=
+target2.width=100
+target2.x=270
+target2.y=60
+target3.editor.height=730
+target3.editor.width=792
+target3.editor.x=53
+target3.editor.y=60
+target3.height=50
+target3.name=Demo
+target3.naviview.expanded=true
+target3.showInterface=false
+target3.type=ClassTarget
+target3.typeParameters=
+target3.width=80
+target3.x=50
+target3.y=130
+target4.editor.height=810
+target4.editor.width=976
+target4.editor.x=53
+target4.editor.y=23
+target4.height=50
+target4.name=Taxi
+target4.naviview.expanded=false
+target4.showInterface=false
+target4.type=ClassTarget
+target4.typeParameters=
+target4.width=80
+target4.x=440
+target4.y=210
+target5.editor.height=737
+target5.editor.width=839
+target5.editor.x=53
+target5.editor.y=60
+target5.height=50
+target5.name=Passenger
+target5.naviview.expanded=true
+target5.showInterface=false
+target5.type=ClassTarget
+target5.typeParameters=
+target5.width=90
+target5.x=360
+target5.y=310
+target6.editor.height=737
+target6.editor.width=837
+target6.editor.x=53
+target6.editor.y=60
+target6.height=50
+target6.name=PassengerSource
+target6.naviview.expanded=true
+target6.showInterface=false
+target6.type=ClassTarget
+target6.typeParameters=
+target6.width=130
+target6.x=120
+target6.y=230
+target7.editor.height=733
+target7.editor.width=838
+target7.editor.x=53
+target7.editor.y=60
+target7.height=50
+target7.name=Shuttle
+target7.naviview.expanded=false
+target7.showInterface=false
+target7.type=ClassTarget
+target7.typeParameters=
+target7.width=80
+target7.x=570
+target7.y=210
+target8.editor.height=737
+target8.editor.width=794
+target8.editor.x=53
+target8.editor.y=60
+target8.height=50
+target8.name=Location
+target8.naviview.expanded=true
+target8.showInterface=false
+target8.type=ClassTarget
+target8.typeParameters=
+target8.width=80
+target8.x=210
+target8.y=380

Semester 1/Programming 1/Java/examples/projects/chapter16/taxi-company-stage-one/Actor.ctxt

@@ -0,0 +1,5 @@
+#BlueJ class context
+comment0.params=
+comment0.target=void\ act()
+comment0.text=\n\ Implement\ the\ actor's\ behavior.\n
+numComments=1

Semester 1/Programming 1/Java/examples/projects/chapter16/taxi-company-stage-one/Actor.java

@@ -0,0 +1,13 @@
+/**
+ * An actor in the taxi-company simulation.
+ * 
+ * @author David J. Barnes and Michael Kölling
+ * @version 2016.02.29
+ */
+public interface Actor
+{
+    /**
+     * Implement the actor's behavior.
+     */
+    public void act();
+}

Semester 1/Programming 1/Java/examples/projects/chapter16/taxi-company-stage-one/Demo.ctxt

@@ -0,0 +1,14 @@
+#BlueJ class context
+comment0.params=
+comment0.target=Demo()
+comment0.text=\n\ Constructor\ for\ objects\ of\ class\ Demo\n
+comment1.params=
+comment1.target=void\ run()
+comment1.text=\n\ Run\ the\ demo\ for\ a\ fixed\ number\ of\ steps.\n
+comment2.params=
+comment2.target=void\ step()
+comment2.text=\n\ Run\ the\ demo\ for\ one\ step\ by\ requesting\n\ all\ actors\ to\ act.\n
+comment3.params=
+comment3.target=void\ reset()
+comment3.text=\n\ Reset\ the\ demo\ to\ a\ starting\ point.\n\ A\ single\ taxi\ is\ created,\ and\ a\ pickup\ is\n\ requested\ for\ a\ single\ passenger.\n\ @throws\ IllegalStateException\ If\ a\ pickup\ cannot\ be\ found\n
+numComments=4

Semester 1/Programming 1/Java/examples/projects/chapter16/taxi-company-stage-one/Demo.java

@@ -0,0 +1,69 @@
+import java.util.Iterator;
+import java.util.List;
+import java.util.LinkedList;
+
+/**
+ * Provide a simple demonstration of running a stage-one
+ * scenario. A single passenger is created, and a pickup
+ * requested. As the simulation is run, the passenger
+ * should be picked up and then taken to their destination.
+ * 
+ * @author David J. Barnes and Michael Kölling
+ * @version 2016.02.29
+ */
+public class Demo
+{
+    private List<Actor> actors;
+
+    /**
+     * Constructor for objects of class Demo
+     */
+    public Demo()
+    {
+        actors = new LinkedList<>();
+        reset();
+    }
+    
+    /**
+     * Run the demo for a fixed number of steps.
+     */
+    public void run()
+    {
+        for(int step = 0; step < 100; step++) {
+            step();
+        }
+    }
+
+    /**
+     * Run the demo for one step by requesting
+     * all actors to act.
+     */
+    public void step()
+    {
+        for(Actor actor : actors) {
+            actor.act();
+        }
+    }
+    
+    /**
+     * Reset the demo to a starting point.
+     * A single taxi is created, and a pickup is
+     * requested for a single passenger.
+     * @throws IllegalStateException If a pickup cannot be found
+     */
+    public void reset()
+    {
+        actors.clear();
+        TaxiCompany company = new TaxiCompany();
+        Taxi taxi = new Taxi(company, new Location(10, 10));
+        List<Vehicle> vehicles = company.getVehicles();
+        vehicles.add(taxi);
+        actors.addAll(vehicles);
+        
+        Passenger passenger = new Passenger(new Location(0, 0),
+                                            new Location(10, 20));
+        if(!company.requestPickup(passenger)) {
+            throw new IllegalStateException("Failed to find a pickup.");
+        }
+    }
+}

Semester 1/Programming 1/Java/examples/projects/chapter16/taxi-company-stage-one/Location.ctxt

@@ -0,0 +1,26 @@
+#BlueJ class context
+comment0.params=x\ y
+comment0.target=Location(int,\ int)
+comment0.text=\n\ Model\ a\ location\ in\ the\ city.\n\ @param\ x\ The\ x\ coordinate.\ Must\ be\ positive.\n\ @param\ y\ The\ y\ coordinate.\ Must\ be\ positive.\n\ @throws\ IllegalArgumentException\ If\ a\ coordinate\ is\ negative.\n
+comment1.params=destination
+comment1.target=Location\ nextLocation(Location)
+comment1.text=\n\ Generate\ the\ next\ location\ to\ visit\ in\ order\ to\n\ reach\ the\ destination.\n\ @param\ destination\ Where\ we\ want\ to\ get\ to.\n\ @return\ A\ location\ in\ a\ direct\ line\ from\ this\ to\n\ \ \ \ \ \ \ \ \ destination.\n
+comment2.params=destination
+comment2.target=int\ distance(Location)
+comment2.text=\n\ Determine\ the\ number\ of\ movements\ required\ to\ get\n\ from\ here\ to\ the\ destination.\n\ @param\ destination\ The\ required\ destination.\n\ @return\ The\ number\ of\ movement\ steps.\n
+comment3.params=other
+comment3.target=boolean\ equals(java.lang.Object)
+comment3.text=\n\ Implement\ content\ equality\ for\ locations.\n\ @return\ true\ if\ this\ location\ matches\ the\ other,\n\ \ \ \ \ \ \ \ \ false\ otherwise.\n
+comment4.params=
+comment4.target=java.lang.String\ toString()
+comment4.text=\n\ @return\ A\ representation\ of\ the\ location.\n
+comment5.params=
+comment5.target=int\ hashCode()
+comment5.text=\n\ Use\ the\ top\ 16\ bits\ for\ the\ y\ value\ and\ the\ bottom\ for\ the\ x.\n\ Except\ for\ very\ big\ grids,\ this\ should\ give\ a\ unique\ hash\ code\n\ for\ each\ (x,\ y)\ pair.\n\ @return\ A\ hashcode\ for\ the\ location.\n
+comment6.params=
+comment6.target=int\ getX()
+comment6.text=\n\ @return\ The\ x\ coordinate.\n
+comment7.params=
+comment7.target=int\ getY()
+comment7.text=\n\ @return\ The\ y\ coordinate.\n
+numComments=8

Semester 1/Programming 1/Java/examples/projects/chapter16/taxi-company-stage-one/Location.java

@@ -0,0 +1,117 @@
+/**
+ * Model a location in a city.
+ * 
+ * @author David J. Barnes and Michael Kölling
+ * @version 2016.02.29
+ */
+public class Location
+{
+    private int x;
+    private int y;
+
+    /**
+     * Model a location in the city.
+     * @param x The x coordinate. Must be positive.
+     * @param y The y coordinate. Must be positive.
+     * @throws IllegalArgumentException If a coordinate is negative.
+     */
+    public Location(int x, int y)
+    {
+        if(x < 0) {
+            throw new IllegalArgumentException(
+                        "Negative x-coordinate: " + x);
+        }
+        if(y < 0) {
+            throw new IllegalArgumentException(
+                        "Negative y-coordinate: " + y);
+        }
+        this.x = x;
+        this.y = y;
+    }
+    
+    /**
+     * Generate the next location to visit in order to
+     * reach the destination.
+     * @param destination Where we want to get to.
+     * @return A location in a direct line from this to
+     *         destination.
+     */
+    public Location nextLocation(Location destination)
+    {
+        int destX = destination.getX();
+        int destY = destination.getY();
+        int offsetX = x < destX ? 1 : x > destX ? -1 : 0;
+        int offsetY = y < destY ? 1 : y > destY ? -1 : 0;
+        if(offsetX != 0 || offsetY != 0) {
+            return new Location(x + offsetX, y + offsetY);
+        }
+        else {
+            return destination;
+        }
+    }
+
+    /**
+     * Determine the number of movements required to get
+     * from here to the destination.
+     * @param destination The required destination.
+     * @return The number of movement steps.
+     */
+    public int distance(Location destination)
+    {
+        int xDist = Math.abs(destination.getX() - x);
+        int yDist = Math.abs(destination.getY() - y);
+        return Math.max(xDist, yDist);
+    }
+    
+    /**
+     * Implement content equality for locations.
+     * @return true if this location matches the other,
+     *         false otherwise.
+     */
+    public boolean equals(Object other)
+    {
+        if(other instanceof Location) {
+            Location otherLocation = (Location) other;
+            return x == otherLocation.getX() &&
+                   y == otherLocation.getY();
+        }
+        else {
+            return false;
+        }
+    }
+    
+    /**
+     * @return A representation of the location.
+     */
+    public String toString()
+    {
+        return "location " + x + "," + y;
+    }
+
+    /**
+     * Use the top 16 bits for the y value and the bottom for the x.
+     * Except for very big grids, this should give a unique hash code
+     * for each (x, y) pair.
+     * @return A hashcode for the location.
+     */
+    public int hashCode()
+    {
+        return (y << 16) + x;
+    }
+
+    /**
+     * @return The x coordinate.
+     */
+    public int getX()
+    {
+        return x;
+    }
+
+    /**
+     * @return The y coordinate.
+     */
+    public int getY()
+    {
+        return y;
+    }
+}

Semester 1/Programming 1/Java/examples/projects/chapter16/taxi-company-stage-one/LocationTest.ctxt

@@ -0,0 +1,19 @@
+#BlueJ class context
+comment0.params=
+comment0.target=LocationTest()
+comment0.text=\n\ Default\ constructor\ for\ test\ class\ LocationTest\n
+comment1.params=
+comment1.target=void\ setUp()
+comment1.text=\n\ Sets\ up\ the\ test\ fixture.\n\n\ Called\ before\ every\ test\ case\ method.\n
+comment2.params=
+comment2.target=void\ tearDown()
+comment2.text=\n\ Tears\ down\ the\ test\ fixture.\n\n\ Called\ after\ every\ test\ case\ method.\n
+comment3.params=
+comment3.target=void\ testDistance()
+comment3.text=\n\ Test\ the\ distance\ method\ of\ the\ Location\ class.\n
+comment4.params=
+comment4.target=void\ testAdjacentLocations()
+comment4.text=\n\ Run\ tests\ of\ the\ nextLocation\ method\ of\ the\ Location\ class.\n
+comment5.params=
+comment5.target=void\ testNonAdjacentLocations()
+numComments=6

Semester 1/Programming 1/Java/examples/projects/chapter16/taxi-company-stage-one/LocationTest.java

@@ -0,0 +1,120 @@
+import static org.junit.Assert.*;
+import org.junit.After;
+import org.junit.Before;
+import org.junit.Test;
+
+/**
+ * Test implementation of the Location class.
+ * 
+ * @author David J. Barnes and Michael Kölling
+ * @version 2016.02.29
+ */
+public class LocationTest
+{
+    /**
+     * Default constructor for test class LocationTest
+     */
+    public LocationTest()
+    {
+    }
+
+    /**
+     * Sets up the test fixture.
+     *
+     * Called before every test case method.
+     */
+    @Before
+    public void setUp()
+    {
+    }
+
+    /**
+     * Tears down the test fixture.
+     *
+     * Called after every test case method.
+     */
+    @After
+    public void tearDown()
+    {
+    }
+    
+    /**
+     * Test the distance method of the Location class.
+     */
+    @Test
+    public void testDistance()
+    {
+        boolean ok = true;
+        int startX = 10, startY = 10;
+        Location startLocation = new Location(startX, startY);
+        
+        // Calculate the distance from startLocation to other
+        // locations around it. The distance should always
+        // be equal to offset.
+        int offset = 5;
+        assertEquals(startLocation.distance(
+            new Location(startX, startY + offset)), offset);
+        assertEquals(startLocation.distance(
+            new Location(startX + offset, startY)), offset);
+        assertEquals(startLocation.distance(
+            new Location(startX + 1, startY + offset)), offset);
+        assertEquals(startLocation.distance(
+            new Location(startX + offset, startY + 1)), offset);
+        assertEquals(startLocation.distance(
+            new Location(startX + offset, startY + offset)), offset);
+        assertEquals(startLocation.distance(
+            new Location(startX + offset - 1, startY + offset)), offset);
+        assertEquals(startLocation.distance(
+            new Location(startX + offset, startY + offset - 1)), offset);
+    }
+    
+    /**
+     * Run tests of the nextLocation method of the Location class.
+     */
+    @Test
+    public void testAdjacentLocations()
+    {
+        int startX = 10, startY = 10;
+        Location startLocation = new Location(startX, startY);
+        
+        // Test immediate adjacency.
+        // (x, y) offsets for each direction from (startX, startY).
+        int[][] offsets = {
+            { 0, 1, 0, 1, -1, 0, -1, 1, -1},
+            { 0, 0, 1, 1, 0, -1, -1, -1, 1},
+        };
+
+        for(int i = 0; i < offsets[0].length; i++) {
+            Location destination = new Location(startX + offsets[0][i],
+                                       startY + offsets[1][i]);
+            Location nextLocation = startLocation.nextLocation(destination);
+            assertEquals(nextLocation.equals(destination), true);
+        }
+    }
+    
+    @Test
+    public void testNonAdjacentLocations()
+    {
+        int startX = 10, startY = 10;
+        Location startLocation = new Location(startX, startY);
+        // (x, y) offsets for each direction from (startX, startY).
+        int[][] offsets = {
+            { 0, 1, 0, 1, -1, 0, -1, 1, -1},
+            { 0, 0, 1, 1, 0, -1, -1, -1, 1},
+        };
+        // Test with destination that are not adjacent.
+        // Use different values for xDist and yDist for more
+        // varied tests.
+        int xDist = 7;
+        int yDist = 3;
+        for(int i = 0; i < offsets[0].length; i++) {
+            Location destination = new Location(startX + xDist * offsets[0][i],
+                                       startY + yDist * offsets[1][i]);
+            Location expectedNextLocation =
+                        new Location(startX + offsets[0][i],
+                                     startY + offsets[1][i]);
+            Location nextLocation = startLocation.nextLocation(destination);            
+            assertEquals(expectedNextLocation.equals(nextLocation), true);
+        }
+    }
+}

Semester 1/Programming 1/Java/examples/projects/chapter16/taxi-company-stage-one/MissingPassengerException.ctxt

@@ -0,0 +1,8 @@
+#BlueJ class context
+comment0.params=vehicle
+comment0.target=MissingPassengerException(Vehicle)
+comment0.text=\n\ Constructor\ for\ objects\ of\ class\ MissingPassengerException.\n\ @param\ vehicle\ The\ vehicle\ expecting\ a\ passenger.\n
+comment1.params=
+comment1.target=Vehicle\ getVehicle()
+comment1.text=\n\ @return\ The\ vehicle\ for\ which\ there\ was\ no\ passenger.\n
+numComments=2

Semester 1/Programming 1/Java/examples/projects/chapter16/taxi-company-stage-one/MissingPassengerException.java

@@ -0,0 +1,27 @@
+
+/**
+ * Indicate that there was no passenger at a pickup point.
+ * 
+ * @author David J. Barnes and Michael Kölling
+ * @version 2016.02.29
+ */
+public class MissingPassengerException extends RuntimeException
+{
+    private Vehicle vehicle;
+    /**
+     * Constructor for objects of class MissingPassengerException.
+     * @param vehicle The vehicle expecting a passenger.
+     */
+    public MissingPassengerException(Vehicle vehicle)
+    {
+        super("Missing passenger at pickup location.");
+    }
+
+    /**
+     * @return The vehicle for which there was no passenger.
+     */
+    public Vehicle getVehicle()
+    {
+        return vehicle;
+    }
+}

Semester 1/Programming 1/Java/examples/projects/chapter16/taxi-company-stage-one/Passenger.ctxt

@@ -0,0 +1,13 @@
+#BlueJ class context
+comment0.params=pickup\ destination
+comment0.target=Passenger(Location,\ Location)
+comment0.text=\n\ Constructor\ for\ objects\ of\ class\ Passenger\n\ @param\ pickup\ The\ pickup\ location,\ must\ not\ be\ null.\n\ @param\ destination\ The\ destination\ location,\ must\ not\ be\ null.\n\ @throws\ NullPointerException\ If\ either\ location\ is\ null.\n
+comment1.params=
+comment1.target=java.lang.String\ toString()
+comment2.params=
+comment2.target=Location\ getPickupLocation()
+comment2.text=\n\ @return\ The\ pickup\ location.\n
+comment3.params=
+comment3.target=Location\ getDestination()
+comment3.text=\n\ @return\ The\ destination\ location.\n
+numComments=4

Semester 1/Programming 1/Java/examples/projects/chapter16/taxi-company-stage-one/Passenger.java

@@ -0,0 +1,52 @@
+/**
+ * Model a passenger wishing to get from one
+ * location to another.
+ * 
+ * @author David J. Barnes and Michael Kölling
+ * @version 2016.02.29
+ */
+public class Passenger
+{
+    private Location pickup;
+    private Location destination;
+
+    /**
+     * Constructor for objects of class Passenger
+     * @param pickup The pickup location, must not be null.
+     * @param destination The destination location, must not be null.
+     * @throws NullPointerException If either location is null.
+     */
+    public Passenger(Location pickup, Location destination)
+    {
+        if(pickup == null) {
+            throw new NullPointerException("Pickup location");
+        }
+        if(destination == null) {
+            throw new NullPointerException("Destination location");
+        }
+        this.pickup = pickup;
+        this.destination = destination;
+    }
+    
+    public String toString()
+    {
+        return "Passenger travelling from " +
+               pickup + " to " + destination;
+    }
+
+    /**
+     * @return The pickup location.
+     */
+    public Location getPickupLocation()
+    {
+        return pickup;
+    }
+    
+    /**
+     * @return The destination location.
+     */
+    public Location getDestination()
+    {
+        return destination;
+    }
+}

Semester 1/Programming 1/Java/examples/projects/chapter16/taxi-company-stage-one/PassengerSource.ctxt

@@ -0,0 +1,11 @@
+#BlueJ class context
+comment0.params=company
+comment0.target=PassengerSource(TaxiCompany)
+comment0.text=\n\ Constructor\ for\ objects\ of\ class\ PassengerSource.\n\ @param\ company\ The\ company\ to\ be\ used.\ Must\ not\ be\ null.\n\ @throws\ NullPointerException\ if\ company\ is\ null.\n
+comment1.params=
+comment1.target=boolean\ requestPickup()
+comment1.text=\n\ Have\ the\ source\ generate\ a\ new\ passenger\ and\n\ request\ a\ pickup\ from\ the\ company.\n\ @return\ true\ If\ the\ request\ succeeds,\ false\ otherwise.\n
+comment2.params=
+comment2.target=Passenger\ createPassenger()
+comment2.text=\n\ Create\ a\ new\ passenger.\n\ @return\ The\ created\ passenger.\n
+numComments=3

Semester 1/Programming 1/Java/examples/projects/chapter16/taxi-company-stage-one/PassengerSource.java

@@ -0,0 +1,44 @@
+/**
+ * Simulate passengers requesting rides from a taxi company.
+ * Passengers should be generated at random intervals.
+ * 
+ * @author David J. Barnes and Michael Kölling
+ * @version 2016.02.29
+ */
+public class PassengerSource
+{
+    private TaxiCompany company;
+
+    /**
+     * Constructor for objects of class PassengerSource.
+     * @param company The company to be used. Must not be null.
+     * @throws NullPointerException if company is null.
+     */
+    public PassengerSource(TaxiCompany company)
+    {
+        if(company == null) {
+            throw new NullPointerException("company");
+        }
+        this.company = company;
+    }
+
+    /**
+     * Have the source generate a new passenger and
+     * request a pickup from the company.
+     * @return true If the request succeeds, false otherwise.
+     */
+    public boolean requestPickup()
+    {
+        Passenger passenger = createPassenger();
+        return company.requestPickup(passenger);
+    }
+
+    /**
+     * Create a new passenger.
+     * @return The created passenger.
+     */
+    public Passenger createPassenger()
+    {
+        return new Passenger(new Location(0, 0), new Location(10, 20));
+    }
+}

Semester 1/Programming 1/Java/examples/projects/chapter16/taxi-company-stage-one/PassengerSourceTest.ctxt

@@ -0,0 +1,14 @@
+#BlueJ class context
+comment0.params=
+comment0.target=PassengerSourceTest()
+comment0.text=\n\ Default\ constructor\ for\ test\ class\ PassengerSourceTest\n
+comment1.params=
+comment1.target=void\ setUp()
+comment1.text=\n\ Sets\ up\ the\ test\ fixture.\n\n\ Called\ before\ every\ test\ case\ method.\n
+comment2.params=
+comment2.target=void\ tearDown()
+comment2.text=\n\ Tears\ down\ the\ test\ fixture.\n\n\ Called\ after\ every\ test\ case\ method.\n
+comment3.params=
+comment3.target=void\ testPickup()
+comment3.text=\n\ Test\ for\ successful\ pickup\ of\ a\ passenger.\n
+numComments=4

Semester 1/Programming 1/Java/examples/projects/chapter16/taxi-company-stage-one/PassengerSourceTest.java

@@ -0,0 +1,59 @@
+import java.util.List;
+import static org.junit.Assert.*;
+import org.junit.After;
+import org.junit.Before;
+import org.junit.Test;
+
+/**
+ * The test class PassengerSourceTest.
+ *
+ * @author David J. Barnes and Michael Kölling
+ * @version 2016.02.29
+ */
+public class PassengerSourceTest
+{
+    private PassengerSource source;
+    
+    /**
+     * Default constructor for test class PassengerSourceTest
+     */
+    public PassengerSourceTest()
+    {
+    }
+
+    /**
+     * Sets up the test fixture.
+     *
+     * Called before every test case method.
+     */
+    @Before
+    public void setUp()
+    {
+        TaxiCompany company = new TaxiCompany();
+        source = new PassengerSource(company);
+        Location taxiLocation = new Location(0, 0);
+        Taxi taxi = new Taxi(company, taxiLocation);
+        List<Vehicle> vehicles = company.getVehicles();
+        vehicles.add(taxi);
+    }
+
+    /**
+     * Tears down the test fixture.
+     *
+     * Called after every test case method.
+     */
+    @After
+    public void tearDown()
+    {
+        source = null;
+    }
+
+    /**
+     * Test for successful pickup of a passenger.
+     */
+    @Test
+    public void testPickup()
+    {
+        assertEquals(true, source.requestPickup());
+    }
+}

Semester 1/Programming 1/Java/examples/projects/chapter16/taxi-company-stage-one/PassengerTest.ctxt

@@ -0,0 +1,14 @@
+#BlueJ class context
+comment0.params=
+comment0.target=PassengerTest()
+comment0.text=\n\ Default\ constructor\ for\ test\ class\ PassengerTest\n
+comment1.params=
+comment1.target=void\ setUp()
+comment1.text=\n\ Sets\ up\ the\ test\ fixture.\n\n\ Called\ before\ every\ test\ case\ method.\n
+comment2.params=
+comment2.target=void\ tearDown()
+comment2.text=\n\ Tears\ down\ the\ test\ fixture.\n\n\ Called\ after\ every\ test\ case\ method.\n
+comment3.params=
+comment3.target=void\ testCreation()
+comment3.text=\n\ Test\ basic\ creation\ of\ a\ passenger.\n\ Ensure\ that\ the\ pickup\ and\ destination\ locations\n\ have\ been\ set.\n
+numComments=4

Semester 1/Programming 1/Java/examples/projects/chapter16/taxi-company-stage-one/PassengerTest.java

@@ -0,0 +1,55 @@
+import static org.junit.Assert.*;
+import org.junit.After;
+import org.junit.Before;
+import org.junit.Test;
+
+/**
+ * The test class PassengerTest.
+ *
+ * @author  David J. Barnes and Michael Kölling
+ * @version 2016.02.29
+ */
+public class PassengerTest
+{
+    /**
+     * Default constructor for test class PassengerTest
+     */
+    public PassengerTest()
+    {
+    }
+
+    /**
+     * Sets up the test fixture.
+     *
+     * Called before every test case method.
+     */
+    @Before
+    public void setUp()
+    {
+    }
+
+    /**
+     * Tears down the test fixture.
+     *
+     * Called after every test case method.
+     */
+    @After
+    public void tearDown()
+    {
+    }
+
+    /**
+     * Test basic creation of a passenger.
+     * Ensure that the pickup and destination locations
+     * have been set.
+     */
+    @Test
+	public void testCreation()
+	{
+		Location pickup = new Location(0, 0);
+		Location destination = new Location(1, 2);
+		Passenger passenger1 = new Passenger(pickup, destination);
+		assertEquals(destination, passenger1.getDestination());
+		assertEquals(pickup, passenger1.getPickupLocation());
+	}
+}

Semester 1/Programming 1/Java/examples/projects/chapter16/taxi-company-stage-one/README.TXT

@@ -0,0 +1,21 @@
+Project: taxi-company-stage-one
+Authors: David J. Barnes and Michael Kölling
+
+This project is part of the material for chapter 14 of the book
+
+   Objects First with Java - A Practical Introduction using BlueJ
+   Sixth edition
+   David J. Barnes and Michael Kölling
+   Pearson Education, 2016
+
+This project provides a partial implementation of a simulation of
+taxis operating on a city grid to pick up and transport passengers.
+    
+This is the third stage of this project. It illustrates the 
+implementation of a first stage of the project.
+
+How to start this project:
+    Create a Demo object and invoke its demo method.
+    A single taxi carries a single passenger to their destination.
+
+The test classes provide a little testing of basic functionality.

Semester 1/Programming 1/Java/examples/projects/chapter16/taxi-company-stage-one/Shuttle.ctxt

@@ -0,0 +1,23 @@
+#BlueJ class context
+comment0.params=company\ location
+comment0.target=Shuttle(TaxiCompany,\ Location)
+comment0.text=\n\ Constructor\ for\ objects\ of\ class\ Shuttle\n\ @param\ company\ The\ taxi\ company.\ Must\ not\ be\ null.\n\ @param\ location\ The\ vehicle's\ starting\ point.\ Must\ not\ be\ null.\n\ @throws\ NullPointerException\ If\ company\ or\ location\ is\ null.\n
+comment1.params=
+comment1.target=void\ act()
+comment1.text=\n\ Carry\ out\ a\ shuttle's\ actions.\n
+comment2.params=
+comment2.target=boolean\ isFree()
+comment2.text=\n\ Is\ the\ shuttle\ free?\n\ @return\ Whether\ or\ not\ this\ vehicle\ is\ free.\n
+comment3.params=location
+comment3.target=void\ setPickupLocation(Location)
+comment3.text=\n\ Receive\ a\ pickup\ location.\n\ @param\ location\ The\ pickup\ location.\n
+comment4.params=passenger
+comment4.target=void\ pickup(Passenger)
+comment4.text=\n\ Receive\ a\ passenger.\n\ Add\ their\ destination\ to\ the\ list.\n\ @param\ passenger\ The\ passenger.\n
+comment5.params=
+comment5.target=void\ chooseTargetLocation()
+comment5.text=\n\ Decide\ where\ to\ go\ next,\ based\ on\ the\ list\ of\n\ possible\ destinations.\n
+comment6.params=
+comment6.target=void\ offloadPassenger()
+comment6.text=\n\ Offload\ a\ passenger\ whose\ destination\ is\ the\n\ current\ location.\n
+numComments=7

Semester 1/Programming 1/Java/examples/projects/chapter16/taxi-company-stage-one/Shuttle.java

@@ -0,0 +1,83 @@
+import java.util.List;
+import java.util.LinkedList;
+    
+/**
+ * A shuttle is able to carry multiple passengers.
+ * 
+ * @author David J. Barnes and Michael Kölling
+ * @version 2016.02.29
+ */
+public class Shuttle extends Vehicle
+{
+    // The list of destinations for the shuttle.
+    private List<Location> destinations;
+    // The list of passengers on the shuttle.
+    private List<Passenger> passengers;
+
+    /**
+     * Constructor for objects of class Shuttle
+     * @param company The taxi company. Must not be null.
+     * @param location The vehicle's starting point. Must not be null.
+     * @throws NullPointerException If company or location is null.
+     */
+    public Shuttle(TaxiCompany company, Location location)
+    {
+        super(company, location);
+        destinations = new LinkedList<>();
+        passengers = new LinkedList<>();
+    }
+
+    /**
+     * Carry out a shuttle's actions.
+     */
+    public void act()
+    {
+    }
+
+    /**
+     * Is the shuttle free?
+     * @return Whether or not this vehicle is free.
+     */
+    public boolean isFree()
+    {
+        return true;
+    }
+    
+    /**
+     * Receive a pickup location.
+     * @param location The pickup location.
+     */
+    public void setPickupLocation(Location location)
+    {
+        destinations.add(location);
+        chooseTargetLocation();
+    }
+    
+    /**
+     * Receive a passenger.
+     * Add their destination to the list.
+     * @param passenger The passenger.
+     */
+    public void pickup(Passenger passenger)
+    {
+        passengers.add(passenger);
+        destinations.add(passenger.getDestination());
+        chooseTargetLocation();
+    }
+
+    /**
+     * Decide where to go next, based on the list of
+     * possible destinations.
+     */
+    private void chooseTargetLocation()
+    {
+    }
+
+    /**
+     * Offload a passenger whose destination is the
+     * current location.
+     */
+    public void offloadPassenger()
+    {
+    }
+}

Semester 1/Programming 1/Java/examples/projects/chapter16/taxi-company-stage-one/Taxi.ctxt

@@ -0,0 +1,23 @@
+#BlueJ class context
+comment0.params=company\ location
+comment0.target=Taxi(TaxiCompany,\ Location)
+comment0.text=\n\ Constructor\ for\ objects\ of\ class\ Taxi\n\ @param\ company\ The\ taxi\ company.\ Must\ not\ be\ null.\n\ @param\ location\ The\ vehicle's\ starting\ point.\ Must\ not\ be\ null.\n\ @throws\ NullPointerException\ If\ company\ or\ location\ is\ null.\n
+comment1.params=
+comment1.target=void\ act()
+comment1.text=\n\ Carry\ out\ a\ taxi's\ actions.\n
+comment2.params=
+comment2.target=boolean\ isFree()
+comment2.text=\n\ Is\ the\ taxi\ free?\n\ @return\ Whether\ or\ not\ this\ taxi\ is\ free.\n
+comment3.params=location
+comment3.target=void\ setPickupLocation(Location)
+comment3.text=\n\ Receive\ a\ pickup\ location.\ This\ becomes\ the\n\ target\ location.\n\ @param\ location\ The\ pickup\ location.\n
+comment4.params=passenger
+comment4.target=void\ pickup(Passenger)
+comment4.text=\n\ Receive\ a\ passenger.\n\ Set\ their\ destination\ as\ the\ target\ location.\n\ @param\ passenger\ The\ passenger.\n
+comment5.params=
+comment5.target=void\ offloadPassenger()
+comment5.text=\n\ Offload\ the\ passenger.\n
+comment6.params=
+comment6.target=java.lang.String\ toString()
+comment6.text=\n\ Return\ details\ of\ the\ taxi,\ such\ as\ where\ it\ is.\n\ @return\ A\ string\ representation\ of\ the\ taxi.\n
+numComments=7

Semester 1/Programming 1/Java/examples/projects/chapter16/taxi-company-stage-one/Taxi.java

@@ -0,0 +1,95 @@
+/**
+ * A taxi is able to carry a single passenger.
+ * 
+ * @author David J. Barnes and Michael Kölling
+ * @version 2016.02.29
+ */
+
+public class Taxi extends Vehicle
+{
+    private Passenger passenger;
+    
+    /**
+     * Constructor for objects of class Taxi
+     * @param company The taxi company. Must not be null.
+     * @param location The vehicle's starting point. Must not be null.
+     * @throws NullPointerException If company or location is null.
+     */
+    public Taxi(TaxiCompany company, Location location)
+    {
+        super(company, location);
+    }
+    
+    /**
+     * Carry out a taxi's actions.
+     */
+    public void act()
+    {
+        Location target = getTargetLocation();
+        if(target != null) {
+            // Find where to move to next.
+            Location next = getLocation().nextLocation(target);
+            setLocation(next);
+            if(next.equals(target)) {
+                if(passenger != null) {
+                    notifyPassengerArrival(passenger);
+                    offloadPassenger();
+                }
+                else {
+                    notifyPickupArrival();
+                }
+            }
+        }
+        else {
+            incrementIdleCount();
+        }
+    }
+
+    /**
+     * Is the taxi free?
+     * @return Whether or not this taxi is free.
+     */
+    public boolean isFree()
+    {
+        return getTargetLocation() == null && passenger == null;
+    }
+    
+    /**
+     * Receive a pickup location. This becomes the
+     * target location.
+     * @param location The pickup location.
+     */
+    public void setPickupLocation(Location location)
+    {
+        setTargetLocation(location);
+    }
+    
+    /**
+     * Receive a passenger.
+     * Set their destination as the target location.
+     * @param passenger The passenger.
+     */
+    public void pickup(Passenger passenger)
+    {
+        this.passenger = passenger;
+        setTargetLocation(passenger.getDestination());
+    }
+
+    /**
+     * Offload the passenger.
+     */
+    public void offloadPassenger()
+    {
+        passenger = null;
+        clearTargetLocation();
+    }
+    
+    /**
+     * Return details of the taxi, such as where it is.
+     * @return A string representation of the taxi.
+     */
+    public String toString()
+    {
+        return "Taxi at " + getLocation();
+    }
+}

Semester 1/Programming 1/Java/examples/projects/chapter16/taxi-company-stage-one/TaxiCompany.ctxt

@@ -0,0 +1,20 @@
+#BlueJ class context
+comment0.params=
+comment0.target=TaxiCompany()
+comment0.text=\n\ Constructor\ for\ objects\ of\ class\ TaxiCompany\n
+comment1.params=passenger
+comment1.target=boolean\ requestPickup(Passenger)
+comment1.text=\n\ Request\ a\ pickup\ for\ the\ given\ passenger.\n\ @param\ passenger\ The\ passenger\ requesting\ a\ pickup.\n\ @return\ Whether\ a\ free\ vehicle\ is\ available.\n
+comment2.params=vehicle
+comment2.target=void\ arrivedAtPickup(Vehicle)
+comment2.text=\n\ A\ vehicle\ has\ arrived\ at\ a\ pickup\ point.\n\ @param\ vehicle\ The\ vehicle\ at\ the\ pickup\ point.\n\ @throws\ MissingPassengerException\ If\ there\ is\ no\ passenger\ waiting.\n
+comment3.params=vehicle\ passenger
+comment3.target=void\ arrivedAtDestination(Vehicle,\ Passenger)
+comment3.text=\n\ A\ vehicle\ has\ arrived\ at\ a\ passenger's\ destination.\n\ @param\ vehicle\ The\ vehicle\ at\ the\ destination.\n\ @param\ passenger\ The\ passenger\ being\ dropped\ off.\n
+comment4.params=
+comment4.target=java.util.List\ getVehicles()
+comment4.text=\n\ @return\ The\ list\ of\ vehicles.\n
+comment5.params=
+comment5.target=Vehicle\ scheduleVehicle()
+comment5.text=\n\ Find\ a\ free\ vehicle,\ if\ any.\n\ @return\ A\ free\ vehicle,\ or\ null\ if\ there\ is\ none.\n
+numComments=6