first commit

2024-01-15 20:14:10 +00:00
commit 8c81ee28b7
3106 changed files with 474415 additions and 0 deletions
--- a/1/Java/examples/projects/chapter12/foxes-and-rabbits-graph/FieldStats.java
+++ b/1/Java/examples/projects/chapter12/foxes-and-rabbits-graph/FieldStats.java
@@ -0,0 +1,142 @@
+import java.awt.Color;
+import java.util.HashMap;
+
+/**
+ * This class collects and provides some statistical data on the state 
+ * of a field. It is flexible: it will create and maintain a counter 
+ * for any class of object that is found within the field.
+ * 
+ * @author David J. Barnes and Michael Kölling
+ * @version 2016.02.29
+ */
+public class FieldStats
+{
+    // Counters for each type of entity (fox, rabbit, etc.) in the simulation.
+    private HashMap<Class, Counter> counters;
+    // Whether the counters are currently up to date.
+    private boolean countsValid;
+
+    /**
+     * Construct a FieldStats object.
+     */
+    public FieldStats()
+    {
+        // Set up a collection for counters for each type of animal that
+        // we might find
+        counters = new HashMap<>();
+        countsValid = false;
+    }
+
+    /**
+     * Get details of what is in the field.
+     * @return A string describing what is in the field.
+     */
+    public String getPopulationDetails(Field field)
+    {
+        StringBuffer buffer = new StringBuffer();
+        if(!countsValid) {
+            generateCounts(field);
+        }
+        for(Class key : counters.keySet()) {
+            Counter info = counters.get(key);
+            buffer.append(info.getName());
+            buffer.append(": ");
+            buffer.append(info.getCount());
+            buffer.append(' ');
+        }
+        return buffer.toString();
+    }
+    
+    /**
+     * Get the number of individuals in the population of a given class.
+     * @return  An int with the number for this class.
+     */
+    public int getPopulationCount(Field field, Class key)
+    {
+        if(!countsValid) {
+            generateCounts(field);
+        }
+
+        Counter counter = counters.get(key);
+        return counter.getCount();
+    }
+    
+    /**
+     * Invalidate the current set of statistics; reset all 
+     * counts to zero.
+     */
+    public void reset()
+    {
+        countsValid = false;
+        for(Class key : counters.keySet()) {
+            Counter count = counters.get(key);
+            count.reset();
+        }
+    }
+
+    /**
+     * Increment the count for one class of animal.
+     * @param animalClass The class of animal to increment.
+     */
+    public void incrementCount(Class animalClass)
+    {
+        Counter count = counters.get(animalClass);
+        if(count == null) {
+            // We do not have a counter for this species yet.
+            // Create one.
+            count = new Counter(animalClass.getName());
+            counters.put(animalClass, count);
+        }
+        count.increment();
+    }
+
+    /**
+     * Indicate that an animal count has been completed.
+     */
+    public void countFinished()
+    {
+        countsValid = true;
+    }
+
+    /**
+     * Determine whether the simulation is still viable.
+     * I.e., should it continue to run.
+     * @return true If there is more than one species alive.
+     */
+    public boolean isViable(Field field)
+    {
+        // How many counts are non-zero.
+        int nonZero = 0;
+        if(!countsValid) {
+            generateCounts(field);
+        }
+        for(Class key : counters.keySet()) {
+            Counter info = counters.get(key);
+            if(info.getCount() > 0) {
+                nonZero++;
+            }
+        }
+        return nonZero > 1;
+    }
+    
+    /**
+     * Generate counts of the number of foxes and rabbits.
+     * These are not kept up to date as foxes and rabbits
+     * are placed in the field, but only when a request
+     * is made for the information.
+     * @param field The field to generate the stats for.
+     */
+    private void generateCounts(Field field)
+    {
+        reset();
+        for(int row = 0; row < field.getDepth(); row++) {
+            for(int col = 0; col < field.getWidth(); col++) {
+                Object animal = field.getObjectAt(row, col);
+                if(animal != null) {
+                    incrementCount(animal.getClass());
+                }
+            }
+        }
+        countsValid = true;
+    }
+}