vault backup: 2024-03-05 13:01:43

2024-03-05 13:01:43 +00:00
parent 8f7a395bdb
commit 8ce640b4ba
44 changed files with 1177 additions and 177 deletions
--- a/.obsidian/workspace.json
+++ b/.obsidian/workspace.json
@@ -7,16 +7,6 @@
        "id": "74175e978d06be55",
        "type": "tabs",
        "children": [
-          {
-            "id": "6ff62909f822ba9b",
-            "type": "leaf",
-            "state": {
-              "type": "pdf",
-              "state": {
-                "file": "Semester 2/Database Systems/Exercise Booklet.pdf"
-              }
-            }
-          },
          {
            "id": "90e6fc52439b47f9",
            "type": "leaf",
@@ -37,8 +27,7 @@
              "state": {}
            }
          }
-        ],
-        "currentTab": 1
+        ]
      },
      {
        "id": "1177e1c9853f407d",
@@ -53,8 +42,19 @@
                "file": "Semester 2/Database Systems/Exercise Booklet.pdf"
              }
            }
+          },
+          {
+            "id": "e96e468fb0a709e5",
+            "type": "leaf",
+            "state": {
+              "type": "pdf",
+              "state": {
+                "file": "Semester 2/Database Systems/Booklet of Lecture Slides for Semester Two (2).pdf"
              }
-        ]
+            }
+          }
+        ],
+        "currentTab": 1
      }
    ],
    "direction": "vertical"
@@ -121,7 +121,7 @@
            "state": {
              "type": "backlink",
              "state": {
-                "file": "Semester 2/Database Systems/Week 7/Week 7 Database Systems.md",
+                "file": "Semester 2/Database Systems/Booklet of Lecture Slides for Semester Two (2).pdf",
                "collapseAll": false,
                "extraContext": false,
                "sortOrder": "alphabetical",
@@ -138,7 +138,7 @@
            "state": {
              "type": "outgoing-link",
              "state": {
-                "file": "Semester 2/Database Systems/Week 7/Week 7 Database Systems.md",
+                "file": "Semester 2/Database Systems/Booklet of Lecture Slides for Semester Two (2).pdf",
                "linksCollapsed": false,
                "unlinkedCollapsed": true
              }
@@ -161,7 +161,7 @@
            "state": {
              "type": "outline",
              "state": {
-                "file": "Semester 2/Database Systems/Week 7/Week 7 Database Systems.md"
+                "file": "Semester 2/Database Systems/Booklet of Lecture Slides for Semester Two (2).pdf"
              }
            }
          },
@@ -201,22 +201,25 @@
      "switcher:Open quick switcher": false
    }
  },
-  "active": "90e6fc52439b47f9",
+  "active": "e96e468fb0a709e5",
  "lastOpenFiles": [
+    "Semester 2/Database Systems/Week 7/Week 7 Database Systems.md",
+    "Semester 2/Programming 2/Project/Part 2/Book.java#",
+    "Semester 2/Programming 2/Project/Part 2/Periodical.java#",
+    "Semester 2/Programming 2/Project/Part 2/LibraryItem.java#",
+    "Semester 2/Programming 2/Project/Part 2/Library.java#",
+    "images/Pasted image 20240227171728.png",
+    "images/Pasted image 20240227171700.png",
+    "Semester 2/Database Systems/Booklet of Lecture Slides for Semester Two (2).pdf",
+    "images/Pasted image 20240227171626.png",
    "images/Pasted image 20240227162324.png",
    "images/Pasted image 20240227161946.png",
    "images/Pasted image 20240227161426.png",
    "Semester 2/Database Systems/Exercise Booklet.pdf",
-    "Semester 2/Database Systems/Booklet of Lecture Slides for Semester Two (2).pdf",
-    "Semester 2/Database Systems/Week 7/Week 7 Database Systems.md",
    "images/Pasted image 20240227133544.png",
    "images/Pasted image 20240227133521.png",
    "images/Pasted image 20240227132816.png",
    "images/Pasted image 20240227132741.png",
-    "images/Pasted image 20240227132007.png",
-    "images/Pasted image 20240227131954.png",
-    "images/Pasted image 20240227131936.png",
-    "images/Pasted image 20240227131321.png",
    "Semester 2/Database Systems/Week 7",
    "Semester 2/Database Systems/Week 6/Week 6 Database Systems.md",
    "Semester 2/Computer Systems Internals & Linux/Week 6/Week 6 Computer Systems Internals.md",
@@ -228,10 +231,6 @@
    "Semester 2/Programming 2/Assessment 3 Revision",
    "Semester 2/Database Systems/Week 5/Week 5 Database Systems.md",
    "Semester 2/Database Systems/Week 6",
-    "Semester 2/Programming 2/Project/Part 2/Library.java#",
-    "Semester 2/Programming 2/Project/Part 2/Periodical.java#",
-    "Semester 2/Programming 2/Project/Part 2/data/item_data_2.txt",
-    "Semester 2/Programming 2/Project/Part 2/data/item_data_1_v2.txt",
    "Semester 2/Database Systems/Week 4/Week 4 Database Systems.md",
    "Semester 2/HCI/Week 2/Week 2 Human Computer Interfaces.md",
    "Semester 2/HCI/Week 3/Week 3 Human Computer Interfaces.md",
--- a/Systems/Week
+++ b/Systems/Week
@@ -102,12 +102,149 @@ Several issues that DBMS needs to address
 | T1          | X      |             |
 | T2          | Z      |             |
 | T3          |        | Z           |
+
 ![](Pasted%20image%2020240227161426.png)

-3. ![](Pasted%20image%2020240227161946.png)
+1. ![](Pasted%20image%2020240227161946.png)
 There is no deadlock since there are no cycles.

-4. ![](Pasted%20image%2020240227162324.png)
+2. ![](Pasted%20image%2020240227162324.png)
 There may be a deadlock, since there are multiple cycles in the WFG

 # Database Recovery Part 1
+
+Database recovery is the process of restoring the database to a correct state after a failure
+
+## Types of Failures
+
+- Media Failures
+	- Hard Disk head crashes
+	- Loss of secondary storage
+- System Crashes
+	- Hardware or software errors
+	- Results in loss of primary storage ( RAM )
+- Application software errors
+	- Logical errors in programs that access the database
+	- Causes one or more transactions to fail
+- Carelessness
+	- Unintentional destruction of data by users or operators
+- Sabotage
+	- Intentional corruption or destruction of data, hardware, or software facilities
+- Natural disasters
+	- Fires, floods, solar flares, earthquakes, power failure, bit flips, etc.
+
+## Facilities Required for Recovery
+
+Log File ( Journal )
+
+- Keeps track of transactions and database changes
+Backups / Snapshots
+- Periodic ( Incremental ) copies of database and journal
+Checkpoint facility
+- Used to make recovery more efficient
+DBMS recovery subsystem ( Recovery Manager )
+- Allows system to restore the database to a consistent state during a failure
+
+Just having backups is not a solution if the facility to recover ( backup protocol ) does not exist.
+
+## Buffers
+
+The database buffers occupy an area of primary storage from which data is transferred to and from secondary storage.
+
+Only when buffers have been written to secondary storage can any updates be regarded permanent.
+
+Flushing can be triggered by:
+
+- Commits
+- Buffer full
+
+## Effects of Failure
+
+- Loss of primary storage ( buffer loss )
+- Loss of database on secondary storage
+
+DBMS recovery subsystem uses techniques that minimise effects
+
+## Atomicity and Durability
+
+Recovery manager is responsible for maintaining atomicity and durability of transactions in event of failure.
+
+### Atomicity
+
+All operations of transaction are performed, or none.
+
+- Recovery manager ensures all effects of committed transactions reach the database, and effects of uncommitted transactions are undone or ignored.
+
+### Durability
+
+Effects of committed transactions are permanent
+
+- Effects must survive both loss of RAM and disk storage.
+
+## Recovery Management
+
+### System Failure
+
+- Transaction can commit once writes are made to database buffers.
+- Updates made to buffer are not automatically written to secondary storage.
+- There may be delay between committing and writing to secondary storage
+	- If system fails during this delay, recovery manager must ensure updates reach the copy of the database on secondary storage.
+- If system failure occurs:
+	- Database buffers are lost
+	- Copy of the database on secondary storage may be incorrect.
+
+### Log File ( Journal )
+
+To keep track of database transactions, the DBMS maintains a journal.
+Two or three copies of the log file are kept on secondary storage due to the importance in the recovery process.
+If the system fails, the log file is examined to see which transactions to redo / which transactions to undo or ignore.
+
+#### Contents of Journal
+
+- Transaction identifier
+- Type of log record
+	- Start, insert, update, delete, abort, commit
+- Identifier of data item affected by database action
+	- Insert, delete, update
+- Before Image
+	- Value of data item before operation of log entry
+- After Image
+	- Value of data item after operation of log entry
+- Log management information
+- Checkpoint records
+
+##### Data Entries
+
+`Start_transaction( T )` - Records transaction T starts execution
+`Write_item( T, X, old_value, new_value )` - Records transaction T changes the value of database item X from the before image to the new image.
+`Read_item( T, X )` - Records transaction T reads the value of database item X. Not always logged.
+`Commit( T )` - Records transaction T has completed all accesses to the database successfully and its effect can be recorded permanently to the database.
+`Checkpoint` - Used to make recovery more efficient. Covered in Part 2.
+
+##### Example 1
+
+![](Pasted%20image%2020240227171626.png)
+
+##### Example 2
+
+Schedule:
+![](Pasted%20image%2020240227171700.png)
+Log File:
+![](Pasted%20image%2020240227171728.png)
+
+### Recovery Rules
+
+- Identify transactions that were committed.
+- Undo / Ignore uncommitted transactions, depending on protocol.
+- Redo committed transactions.
+
+#### Undoing Transactions
+
+- If transaction crash occurs, recovery manager may undo transactions.
+- This is achieved by examining the transaction log and for every write entry, setting the value of item X in the database to the old value.
+- Undoing a number of write item operations from one or more transactions from the log must proceed in the reverse order from the order in which the operations appear in the log.
+
+#### Redoing Transactions
+
+- For every write entry in the transaction log, the value of item X in the database is set to the new value.
+- Redoing a number of write operations from one or more transactions from the log must proceed in the same order in which the operations were written in the log.
--- a/2/AudioVisual.class
+++ b/2/AudioVisual.class
--- a/2/AudioVisual.ctxt
+++ b/2/AudioVisual.ctxt
@@ -0,0 +1,13 @@
+#BlueJ class context
+comment0.params=
+comment0.target=int\ getPlayingTime()
+comment0.text=\n\ Field\ Accessor\ Start\n
+comment1.params=playingTime
+comment1.target=void\ setPlayingTime(int)
+comment1.text=\n\ Field\ Accessor\ End\n\ \n\ Field\ Mutator\ Start\n
+comment2.params=
+comment2.target=void\ printDetails()
+comment2.text=\n\ Field\ Mutator\ End\n
+comment3.params=detailScanner
+comment3.target=void\ readItemData(java.util.Scanner)
+numComments=4
--- a/2/AudioVisual.java
+++ b/2/AudioVisual.java
@@ -0,0 +1,52 @@
+
+/**
+ * Write a description of class AudioVisual here.
+ * 
+ * @author (your name) 
+ * @version (a version number or a date)
+ */
+
+import java.util.Scanner;
+import java.util.ArrayList;
+import java.util.NoSuchElementException;
+
+public abstract class AudioVisual extends LibraryItem
+{
+    private int playingTime;
+    
+    /*
+     * Field Accessor Start
+     */    
+    public int getPlayingTime()
+    {
+        return playingTime;
+    }
+    
+    /*
+     * Field Accessor End
+     * 
+     * Field Mutator Start
+     */
+    
+    public void setPlayingTime( int playingTime )
+    {
+        this.playingTime = playingTime;
+    }
+    
+    /*
+     * Field Mutator End
+     */
+    
+    public void printDetails()
+    {
+        System.out.println( "Playing Time: " + playingTime );
+        super.printDetails();
+    }
+    
+    public void readItemData( Scanner detailScanner ){
+        if ( detailScanner != null ) {
+            this.playingTime = Integer.parseInt( detailScanner.next().trim() );
+            super.readItemData( detailScanner );
+        }
+    }
+}
--- a/2/Project/Part
+++ b/2/Project/Part
--- a/2/Project/Part
+++ b/2/Project/Part
@@ -1,16 +1,14 @@

 /**
- * Subclass of LibraryItem that emulates a Book item in a Library
+ * Subclass of LibraryItem that emulates a Book item.
 * 
 * @George Wilkinson 
 * @1.0
 */

 import java.util.Scanner;
-import java.util.ArrayList;
-import java.util.NoSuchElementException;

-public class Book extends LibraryItem
+public class Book extends PrintedItem
 {
    private String author;
    private String isbn;
@@ -21,11 +19,9 @@ public class Book extends LibraryItem
    public Book(){}
    
    public void printDetails() {
-        System.out.println("\n==================\n( " + getItemCode() + " )" + " ISBN: " + isbn + " Book " + getTitle() + ", written by " + author + ", published by " + getPublisher() + " has " + getNoOfPages() + " pages .\nIt has been borrowed " + getTimesBorrowed() + " times.");
-        if( getOnLoan() )
-            System.out.println( "The Book is currently on loan, and costs " + getCost() + " pence. ");
-        else
-            System.out.println( "The Book is currently not on loan, and costs " + getCost() + " pence. ");
+        System.out.println( "ISBN: " + isbn +
+        "\nAuthor: " + author );
+        super.printDetails();
    }
    
    public void readItemData( Scanner detailScanner ){
--- a/2/Project/Part
+++ b/2/Project/Part
--- a/2/Project/Part
+++ b/2/Project/Part
@@ -0,0 +1,17 @@
+#BlueJ class context
+comment0.params=
+comment0.target=CD()
+comment0.text=\n\ Constructor\ for\ objects\ of\ class\ CD\n
+comment1.params=
+comment1.target=java.lang.String\ getArtist()
+comment2.params=
+comment2.target=int\ noOfTracks()
+comment3.params=artist
+comment3.target=void\ setArtist(java.lang.String)
+comment4.params=noOfTracks
+comment4.target=void\ setNoOfTracks(int)
+comment5.params=
+comment5.target=void\ printDetails()
+comment6.params=detailScanner
+comment6.target=void\ readItemData(java.util.Scanner)
+numComments=7
--- a/2/Project/Part
+++ b/2/Project/Part
@@ -0,0 +1,55 @@
+
+/**
+ * Write a description of class CD here.
+ * 
+ * @author (your name) 
+ * @version (a version number or a date)
+ */
+
+import java.util.Scanner;
+
+public class CD extends AudioVisual
+{
+    private String artist;
+    private int noOfTracks;
+    
+    /**
+     * Constructor for objects of class CD
+     */
+    public CD(){}
+    
+    public String getArtist()
+    {
+        return artist;
+    }
+    
+    public int noOfTracks()
+    {
+        return noOfTracks;
+    }
+    
+    public void setArtist( String artist )
+    {
+        this.artist = artist;
+    }
+    
+    public void setNoOfTracks( int noOfTracks )
+    {
+        this.noOfTracks = noOfTracks;
+    }
+    
+    public void printDetails() {
+        System.out.println( "Artist: " + artist +
+        "\nTrack Count: " + noOfTracks );
+        super.printDetails();
+    }
+    
+    public void readItemData( Scanner detailScanner ){
+        if ( detailScanner != null ) {
+            this.artist = detailScanner.next().trim();
+            this.noOfTracks = Integer.parseInt( detailScanner.next().trim() );
+            super.readItemData( detailScanner );
+        }
+    }
+    
+}
--- a/2/Project/Part
+++ b/2/Project/Part
--- a/2/Project/Part
+++ b/2/Project/Part
@@ -0,0 +1,13 @@
+#BlueJ class context
+comment0.params=
+comment0.target=DVD()
+comment0.text=\n\ Constructor\ for\ objects\ of\ class\ DVD\n
+comment1.params=
+comment1.target=java.lang.String\ getDirector()
+comment2.params=director
+comment2.target=void\ setDirector(java.lang.String)
+comment3.params=
+comment3.target=void\ printDetails()
+comment4.params=detailScanner
+comment4.target=void\ readItemData(java.util.Scanner)
+numComments=5
--- a/2/Project/Part
+++ b/2/Project/Part
@@ -0,0 +1,40 @@
+
+/**
+ * Write a description of class DVD here.
+ * 
+ * @author (your name) 
+ * @version (a version number or a date)
+ */
+
+import java.util.Scanner;
+
+public class DVD extends AudioVisual
+{
+    private String director;
+    /**
+     * Constructor for objects of class DVD
+     */
+    public DVD(){}
+    
+    public String getDirector()
+    {
+        return director;
+    }
+    
+    public void setDirector( String director )
+    {
+        this.director = director;
+    }
+    
+    public void printDetails() {
+        System.out.println( "Director: " + director );
+        super.printDetails();
+    }
+    
+    public void readItemData( Scanner detailScanner ){
+        if ( detailScanner != null ) {
+            this.director = detailScanner.next().trim();
+            super.readItemData( detailScanner );
+        }
+    }
+}
--- a/2/Library.class
+++ b/2/Library.class
--- a/2/Library.ctxt
+++ b/2/Library.ctxt
@@ -5,9 +5,19 @@ comment0.text=\n\ Constructor\ for\ objects\ of\ class\ Library\n
 comment1.params=item
 comment1.target=void\ storeItem(LibraryItem)
 comment1.text=\n\ Appends\ a\ LibraryItem\ to\ the\ itemList.\n
-comment2.params=
-comment2.target=void\ printAllItems()
-comment2.text=\n\ Prints\ to\ the\ terminal\ all\ items\ in\ the\ itemList\n
-comment3.params=
-comment3.target=void\ readItemData()
-numComments=4
+comment2.params=user
+comment2.target=void\ storeUser(LibraryUser)
+comment2.text=\n\ Appends\ a\ LibraryUser\ to\ the\ userList.\n
+comment3.params=prefix\ length
+comment3.target=java.lang.String\ generateUserID(java.lang.String,\ int)
+comment3.text=\n\ Returns\ a\ random\ unique\ user\ ID\ by\ specifying\ \n\ @prefix\ -\ arbitrary\ alphanumeric\ prefix\n\ @length\ -\ length\ of\ numeric\ ID\n\ \n\ Example\:\ length\ \=\ 6,\ expected\ result\ should\ be\ under\ 999,999\ and\ above\ 99,999.\n\ If\ we\ just\ use\ 10^(length),\ this\ would\ generate\ any\ number\ under\ 1,000,000.\n\ This\ is\ an\ issue\ since\ any\ integers\ below\ 100,000\ can\ be\ used,\ which\ would\ be\ incorrect.\n\ By\ using\ the\ offset\ of\ a\ factor\ of\ 10\ below\ the\ desired\ length\ we\ can\ generate\ between\ 0\ and\ 899,999.\n\ After\ this,\ we\ can\ add\ 100,000\ back\ to\ the\ number\ to\ ensure\ a\ baseline\ length\ is\ maintained.\n\ \n\ Note\:\ I\ am\ aware\ that\ this\ is\ overengineered,\ and\ that\ several\ random\ integers\ of\ amount\ @length\ could\ be\ used,\ \n\ but\ this\ is\ considerably\ more\ efficient\ since\ there\ is\ no\ iteration\ involved\ in\ the\ creation\ of\ the\ ID.\ O(1)\n
+comment4.params=
+comment4.target=void\ writeUserData()
+comment4.text=\n\ A\ method\ to\ output\ all\ user\ data\ to\ a\ file\ using\ a\ fileDialog\ to\ specify\ file\ location.\n\ \n\ Note\:\ Potentially\ could\ implement\ the\ HashSet\ made\ for\ GenerateUserID\ to\ avoid\ unnecessary\ recursion.\n
+comment5.params=
+comment5.target=void\ printAll()
+comment5.text=\n\ Prints\ to\ the\ terminal,\ in\ a\ human-readable\ format,\ all\ items\ in\ the\ itemList\n\ \n\ Contains\ a\ marker\ at\ the\ start\ and\ end\ to\ visualise\ in\ terminal\ output.\n
+comment6.params=
+comment6.target=void\ readData()
+comment6.text=\n\ A\ method\ to\ read\ all\ data\ from\ files\ using\ a\ fileDialog\ to\ specify\ file\ location.\n\ This\ will\ create\ the\ corresponding\ objects\ depending\ on\ flags\ contained\ in\ the\ file\n\ and\ populate\ it's\ fields.\n\ \n\ Default\ flag\ value\:\ "book",\ to\ support\ legacy\ files.\ This\ will\ not\ interfere\ with\ \n\ files\ of\ different\ flag\ orders.\n
+numComments=7
--- a/2/Library.java
+++ b/2/Library.java
@@ -1,22 +1,27 @@

 /**
- * Write a description of class Library here.
+ * Class to create objects of a Library, which can hold and report on assets held within
 * 
- * @author (your name) 
- * @version (a version number or a date)
+ * @George Wilkinson
+ * @2.0
 */

 // Import all required libraries. Not using .* as it is not good practice due to potential conflicts.
 import java.util.ArrayList;
+import java.util.HashSet;
 import java.util.Scanner;
+import java.util.Random;
 import java.io.File;
 import java.io.IOException;
 import java.awt.FileDialog;
 import java.awt.Frame;
+import java.io.PrintWriter;

 public class Library
 {
    private ArrayList<LibraryItem> itemList; // Initialise an ArrayList of name itemList to store Library Items
+    private ArrayList<LibraryUser> userList; // Initialise an ArrayList of name userList to store Library Users
+    private HashSet<String> uuidSet; // Initialise a Hash Set of name uuidSet ( unique user identifier ) to store unique user IDs for efficient O(1) searching
    
    /*
     * Constructor for objects of class Library
@@ -24,6 +29,8 @@ public class Library
    public Library()
    {
        itemList = new ArrayList<LibraryItem>();
+        userList = new ArrayList<LibraryUser>();
+        uuidSet = new HashSet<String>();
    }
    
    /*
@@ -35,17 +42,110 @@ public class Library
    }
    
    /*
-     * Prints to the terminal all items in the itemList
+     * Appends a LibraryUser to the userList.
     */
-    public void printAllItems()
+    public void storeUser( LibraryUser user )
    {
-        for( LibraryItem item : itemList )
+        userList.add( user );
+        if ( user.getUserID().equals( "unknown" ) )
        {
-            item.printDetails();
+            user.setUserID( generateUserID( "AB-", 6 ) );
        }
    }
    
-    public void readItemData() //throws IOException
+    /*
+     * Returns a random unique user ID by specifying 
+     * @prefix - arbitrary alphanumeric prefix
+     * @length - length of numeric ID
+     * and returning a unique user id
+     * @uuid - a unique string starting with @prefix, and concat. with a random number
+     * 
+     * Example: length = 6, expected result should be under 999,999 and above 99,999.
+     * If we just use 10^(length), this would generate any number under 1,000,000.
+     * This is an issue since any integers below 100,000 can be used, which would be incorrect.
+     * By using the offset of a factor of 10 below the desired length we can generate between 0 and 899,999.
+     * After this, we can add 100,000 back to the number to ensure a baseline length is maintained.
+     * 
+     * Note: I am aware that this is overengineered, and that several random integers of amount @length could be used, 
+     * but this is considerably more efficient since there is no iteration involved in the creation of the ID. O(1)
+     */
+    public String generateUserID( String prefix, int length )
+    {
+        Random random = new Random();
+        final int offset = (int) Math.pow( 10, (length-1) ); // Static integer equal to 10^(length-1) lower than length. This will allow for the factor to be consistent.
+        int intLength = (int) ( Math.pow( 10, length ) ) - offset ; // Integer equal to 10^(length) minus the offset. This creates a ceiling for the ID range.
+        
+        if ( uuidSet.size() > ( intLength - 1 ) ) { // No idea why I get an error for equals FIX LATER
+            System.out.println("Too many user IDs delegated for current range, increasing ID range by a factor of 10");
+            return generateUserID( prefix, length+1 ); 
+            /* 
+             * This is essential for eliminating a stack overflow error when the specified range is full. This would be incorrect to catch.
+             * By incrementing the length value when the ID range is full, roughly 2.1 billion users can be created without running into an overflow error.
+             */
+        }
+        
+        String uuid = prefix + ( random.nextInt( intLength ) + offset ); 
+        /* 
+         * Sets the uid to the prefix, concat. with a random integer of specified length
+         * Add the offset to a random number, to create a floor to the ID range.
+         */
+        
+        if ( uuidSet.contains( uuid ) )
+        {
+            generateUserID( prefix, length ); // If the ID generated is already contained in the hashset, the method should be called again.
+        }
+        
+        uuidSet.add( uuid ); // Add the UUID to the hash set so it cannot be returned from this method more than once.
+        return uuid;
+    }
+    
+    /*
+     * A method to output all user data to a file using a fileDialog to specify file location.
+     * 
+     * Note: Potentially could implement the HashSet made for GenerateUserID to avoid unnecessary recursion.
+     */
+    public void writeUserData()
+    {
+        try {
+            Frame frame = null; // Initialise null frame
+            FileDialog fileBox = new FileDialog( frame, "Save", FileDialog.SAVE ); // Initialise file dialog box to save written data.
+            fileBox.setVisible( true );
+            PrintWriter writer = new PrintWriter( new File( fileBox.getDirectory() + fileBox.getFile() ) );
+            for ( LibraryUser user : userList ){
+                user.writeData( writer );
+            }
+            writer.close();
+        }
+        catch( IOException e ) { // Catch any IO Exceptions that may occur from improper file selection.
+            System.err.println( "Caught IOException: " + e.getMessage() + "\nAn I/O Exception has occurred, please check file is readable and correct format." );
+        }
+    }
+    
+    /*
+     * Prints to the terminal, in a human-readable format, all items in the itemList
+     * 
+     * Contains a marker at the start and end to visualise in terminal output.
+     */
+    public void printAll()
+    {
+        System.out.println("\n\nStart Detail Print");
+        for( LibraryItem item : itemList )
+        {
+            System.out.println("---------------");
+            item.printDetails();
+        }
+        System.out.println("End Detail Print\n");
+    }
+    
+    /*
+     * A method to read all data from files using a fileDialog to specify file location.
+     * This will create the corresponding objects depending on flags contained in the file
+     * and populate it's fields.
+     * 
+     * Default flag value: "book", to support legacy files. This will not interfere with 
+     * files of different flag orders.
+     */
+    public void readData()
    {
        Frame frame = null; // Initialise a null frame
        FileDialog fileBox = new FileDialog( frame, "Open", FileDialog.LOAD ); // Initialise filebox with the null frame pointer
@@ -53,30 +153,33 @@ public class Library
        
        try {
            Scanner fileScanner = new Scanner( new File( fileBox.getDirectory() + fileBox.getFile() ) );
-            String typeFlag = "";
+            String typeFlag = "book"; // Set a default flag to support legacy files.
            
            while( fileScanner.hasNextLine() ){
                
                String lineItem = fileScanner.nextLine();
-                //System.out.println( lineItem );
                
                // Ensure no comments or empty lines are included
                if ( lineItem.contains( "//" ) || lineItem.trim().isEmpty() ){}
                
                // Check current line is a candidate flag
                else if ( lineItem.startsWith("[" ) ) {
-                    if ( lineItem.toLowerCase().contains("book") ) {
+                    
+                    if ( lineItem.toLowerCase().contains("book") )
                        typeFlag = "book";
-                        //System.out.println( "CHANGED FLAG TO READ BOOKS" );
-                    }
-                    else if ( lineItem.toLowerCase().contains("periodical") ) {
+                    else if ( lineItem.toLowerCase().contains("periodical") )
                        typeFlag = "periodical";
-                        //System.out.println( "CHANGED FLAG TO READ PERIODICALS" );
-                    }  
+                    else if ( lineItem.toLowerCase().contains("cd") )
+                        typeFlag = "cd";
+                    else if ( lineItem.toLowerCase().contains("dvd") )
+                        typeFlag = "dvd";
+                    else if ( lineItem.toLowerCase().contains("user") )
+                        typeFlag = "user";
                    else {
                        System.out.println( "Flag detected, but no accepted format...\n Cannot store item in Library. Changing Flag to generic and skipping the following: ");
                        typeFlag = "generic";
                    }
+                    
                }
                
                // Could be a switch case to be more efficient
@@ -96,8 +199,29 @@ public class Library
                        periodical.readItemData( detailScanner );
                        storeItem( periodical );
                    }
+                    else if ( typeFlag.equals( "cd" ) ) {
+                        //Process CD Data
+                        Scanner detailScanner = new Scanner ( lineItem ).useDelimiter(",");
+                        LibraryItem cd = new CD();
+                        cd.readItemData( detailScanner );
+                        storeItem( cd );
+                    }
+                    else if ( typeFlag.equals( "dvd" ) ) {
+                        //Process DVD Data
+                        Scanner detailScanner = new Scanner ( lineItem ).useDelimiter(",");
+                        LibraryItem dvd = new DVD();
+                        dvd.readItemData( detailScanner );
+                        storeItem( dvd );
+                    }
+                    else if ( typeFlag.equals( "user" ) ) {
+                        //Process User Data
+                        Scanner detailScanner = new Scanner ( lineItem ).useDelimiter(",");
+                        LibraryUser user = new LibraryUser();
+                        user.readData( detailScanner );
+                        storeUser( user );
+                    }
                    else if ( typeFlag.equals( "generic" ) ) {
-                        // Output unaccepted lines
+                        // Output unaccepted lines to terminal
                        System.out.println( lineItem );
                    }
                }
--- a/2/LibraryItem.class
+++ b/2/LibraryItem.class
--- a/2/LibraryItem.ctxt
+++ b/2/LibraryItem.ctxt
@@ -4,34 +4,26 @@ comment0.target=java.lang.String\ getTitle()
 comment0.text=\n\ Field\ Accessor\ Start\n
 comment1.params=
 comment1.target=java.lang.String\ getItemCode()
-comment10.params=timesBorrowed
-comment10.target=void\ setTimesBorrowed(int)
-comment11.params=onLoan
-comment11.target=void\ setOnLoan(boolean)
-comment12.params=noOfPages
-comment12.target=void\ setNoOfPages(int)
-comment13.params=publisher
-comment13.target=void\ setPublisher(java.lang.String)
-comment14.params=
-comment14.target=void\ printDetails()
-comment14.text=\n\ Field\ Mutator\ End\n
-comment15.params=detailScanner
-comment15.target=void\ readItemData(java.util.Scanner)
+comment10.params=
+comment10.target=void\ printDetails()
+comment10.text=\n\ \ \ \ public\ void\ printDetails()\n\ \ \ \ {\n\ \ \ \ \ \ \ \ System.out.println(\ title\ +\ "\ with\ an\ item\ code\ "\ +\ itemCode\ +\ "\ has\ been\ borrowed\ "\ +\ timesBorrowed\ +\ "\ times.");\n\ \ \ \ \ \ \ \ if(\ onLoan\ )\n\ \ \ \ \ \ \ \ \ \ \ \ System.out.println(\ "This\ item\ is\ at\ present\ on\ loan\ and\ when\ new\ cost\ "\ +\ cost\ +\ "\ pence.\\n"\ );\n\ \ \ \ \ \ \ \ else\ \n\ \ \ \ \ \ \ \ \ \ \ \ System.out.println(\ "This\ item\ is\ at\ present\ not\ on\ loan\ and\ when\ new\ cost\ "\ +\ cost\ +\ "\ pence.\\n"\ );\n\ \ \ \ }\n
+comment11.params=detailScanner
+comment11.target=void\ readItemData(java.util.Scanner)
 comment2.params=
 comment2.target=int\ getCost()
 comment3.params=
 comment3.target=int\ getTimesBorrowed()
 comment4.params=
 comment4.target=boolean\ getOnLoan()
-comment5.params=
-comment5.target=int\ getNoOfPages()
-comment6.params=
-comment6.target=java.lang.String\ getPublisher()
-comment7.params=title
-comment7.target=void\ setTitle(java.lang.String)
-comment7.text=\n\ Field\ Accessor\ End\n\ \n\ Field\ Mutator\ Start\n
-comment8.params=itemCode
-comment8.target=void\ setItemCode(java.lang.String)
-comment9.params=cost
-comment9.target=void\ setCost(int)
-numComments=16
+comment5.params=title
+comment5.target=void\ setTitle(java.lang.String)
+comment5.text=\n\ Field\ Accessor\ End\n\ \n\ Field\ Mutator\ Start\n
+comment6.params=itemCode
+comment6.target=void\ setItemCode(java.lang.String)
+comment7.params=cost
+comment7.target=void\ setCost(int)
+comment8.params=timesBorrowed
+comment8.target=void\ setTimesBorrowed(int)
+comment9.params=onLoan
+comment9.target=void\ setOnLoan(boolean)
+numComments=12
--- a/2/LibraryItem.java
+++ b/2/LibraryItem.java
@@ -1,9 +1,9 @@

 /**
- * Emulates an Item in a Library ( 
+ * Superclass of items / assets stored in a Library.
 * 
- * @author (your name) 
- * @version (a version number or a date)
+ * @George Wilkinson
+ * @2.1
 */

 import java.util.Scanner;
@@ -18,8 +18,6 @@ public abstract class LibraryItem
    private int cost;
    private int timesBorrowed;
    private boolean onLoan;
-    private int noOfPages;
-    private String publisher;
    
    /*
     * Field Accessor Start
@@ -49,16 +47,6 @@ public abstract class LibraryItem
        return onLoan;
    }
     
-    public int getNoOfPages()
-    {
-        return noOfPages;
-    }
-    
-    public String getPublisher()
-    {
-        return publisher;
-    }
-    
    /*
     * Field Accessor End
     * 
@@ -90,21 +78,13 @@ public abstract class LibraryItem
        this.onLoan = onLoan;
    }
    
-    public void setNoOfPages( int noOfPages )
-    {
-        this.noOfPages = noOfPages;
-    }
-    
-    public void setPublisher( String publisher )
-    {
-        this.publisher = publisher;
-    }
-    
    /*
     * Field Mutator End
     */
    
    // Output to console the details of the fields in a human-readable format. 
+    
+    /*
    public void printDetails()
    {
        System.out.println( title + " with an item code " + itemCode + " has been borrowed " + timesBorrowed + " times.");
@@ -113,12 +93,23 @@ public abstract class LibraryItem
        else 
            System.out.println( "This item is at present not on loan and when new cost " + cost + " pence.\n" );
    }
+    */
+    
+   public void printDetails()
+   {
+        System.out.println("Item Code: " + itemCode +
+        "\nTitle: " + title +
+        "\nCost: £" + ( ( float )( cost ) )/100 +
+        "\nBorrowed " + getTimesBorrowed() + " times." );
+        if( getOnLoan() )
+            System.out.println( "On Loan");
+        else
+            System.out.println( "Available to Loan");
+   }
   
   public void readItemData( Scanner detailScanner ) {
        
        if ( detailScanner != null ) {
-            this.noOfPages = Integer.parseInt( detailScanner.next().trim() );
-            this.publisher = detailScanner.next().trim();
            this.title = detailScanner.next().trim();
            this.itemCode = detailScanner.next().trim();
            this.cost = Integer.parseInt( detailScanner.next().trim() );
--- a/2/LibraryUser.class
+++ b/2/LibraryUser.class
--- a/2/LibraryUser.ctxt
+++ b/2/LibraryUser.ctxt
@@ -0,0 +1,31 @@
+#BlueJ class context
+comment0.params=
+comment0.target=LibraryUser()
+comment0.text=\n\ Constructor\ for\ objects\ of\ class\ LibraryUser\n
+comment1.params=
+comment1.target=java.lang.String\ getUserID()
+comment10.params=title
+comment10.target=void\ setTitle(java.lang.String)
+comment11.params=writer
+comment11.target=void\ writeData(java.io.PrintWriter)
+comment12.params=
+comment12.target=void\ printDetails()
+comment13.params=detailScanner
+comment13.target=void\ readData(java.util.Scanner)
+comment2.params=
+comment2.target=java.lang.String\ getSurname()
+comment3.params=
+comment3.target=java.lang.String\ getFirstName()
+comment4.params=
+comment4.target=java.lang.String\ getOtherInitials()
+comment5.params=
+comment5.target=java.lang.String\ getTitle()
+comment6.params=userID
+comment6.target=void\ setUserID(java.lang.String)
+comment7.params=surname
+comment7.target=void\ setSurname(java.lang.String)
+comment8.params=firstName
+comment8.target=void\ setFirstName(java.lang.String)
+comment9.params=otherInitials
+comment9.target=void\ setOtherInitials(java.lang.String)
+numComments=14
--- a/2/LibraryUser.java
+++ b/2/LibraryUser.java
@@ -0,0 +1,87 @@
+
+/**
+ * Write a description of class LibraryUser here.
+ * 
+ * @author (your name) 
+ * @version (a version number or a date)
+ */
+
+import java.util.Scanner;
+import java.io.PrintWriter;
+
+public class LibraryUser
+{
+    // instance variables - replace the example below with your own
+    private String userID, surname, firstName, otherInitials, title;
+
+    /**
+     * Constructor for objects of class LibraryUser
+     */
+    public LibraryUser(){}
+
+    public String getUserID(){
+        return userID;
+    }
+    
+    public String getSurname(){
+        return surname;
+    }
+
+    public String getFirstName(){
+        return firstName;
+    }
+    
+    public String getOtherInitials(){
+        return otherInitials;
+    }
+    
+    public String getTitle(){
+        return title;
+    }
+    
+    
+    
+    public void setUserID( String userID ){
+        this.userID = userID;
+    }
+    
+    public void setSurname( String surname ){
+        this.surname = surname;
+    }
+
+    public void setFirstName( String firstName ){
+        this.firstName = firstName;
+    }
+    
+    public void setOtherInitials( String otherInitials ){
+        this.otherInitials = otherInitials;
+    }
+    
+    public void setTitle( String title ){
+        this.title = title;
+    }
+    
+    public void writeData( PrintWriter writer ) 
+    {
+        writer.print(userID + ", " + surname + ", " + firstName + ", " + otherInitials + ", " + title + "\n");
+        writer.flush();
+    }
+    
+    public void printDetails()
+    {
+        System.out.println( "ID: " + userID +
+        "\nName: " + title + " " + firstName + " " + otherInitials + " " + surname );
+    }
+    
+    public void readData( Scanner detailScanner )
+    {
+        if ( detailScanner != null ) {
+            this.userID = detailScanner.next().trim();
+            this.surname = detailScanner.next().trim();
+            this.firstName = detailScanner.next().trim();
+            this.otherInitials = detailScanner.next().trim();
+            this.title = detailScanner.next().trim();
+        }
+    }
+    
+}
--- a/2/Periodical.class
+++ b/2/Periodical.class
--- a/2/Periodical.java
+++ b/2/Periodical.java
@@ -1,24 +1,22 @@

 /**
- * Write a description of class Periodical here.
+ * Subclass of LibraryItem to create a periodical ( e.g. newspaper, tabloid ).
 * 
- * @author (your name) 
- * @version (a version number or a date)
+ * @George Wilkinson
+ * @1.0
 */

 import java.util.Scanner;
-public class Periodical extends LibraryItem
+
+public class Periodical extends PrintedItem
 {
    private String publicationDate;
    
    public Periodical(){}
    
    public void printDetails() {
-        System.out.println("\n==================\n( " + getItemCode() + " )" + " Publication Date: " + publicationDate + " Periodical " + getTitle() + ", published by " + getPublisher() + " has " + getNoOfPages() + " pages .\nIt has been borrowed " + getTimesBorrowed() + " times.");
-        if( getOnLoan() )
-            System.out.println( "The Periodical is currently on loan, and costs " + getCost() + " pence. ");
-        else
-            System.out.println( "The Periodical is currently not on loan, and costs " + getCost() + " pence. ");
+        System.out.println( "Publication Date: " + publicationDate );
+        super.printDetails();
    }
    
    public void readItemData( Scanner detailScanner ){
--- a/2/PrintedItem.class
+++ b/2/PrintedItem.class
--- a/2/PrintedItem.ctxt
+++ b/2/PrintedItem.ctxt
@@ -0,0 +1,17 @@
+#BlueJ class context
+comment0.params=
+comment0.target=int\ getNoOfPages()
+comment0.text=\n\ Field\ Accessor\ Start\n
+comment1.params=
+comment1.target=java.lang.String\ getPublisher()
+comment2.params=noOfPages
+comment2.target=void\ setNoOfPages(int)
+comment2.text=\n\ Field\ Accessor\ End\n\ \n\ Field\ Mutator\ Start\n
+comment3.params=publisher
+comment3.target=void\ setPublisher(java.lang.String)
+comment4.params=
+comment4.target=void\ printDetails()
+comment4.text=\n\ Field\ Mutator\ End\n
+comment5.params=detailScanner
+comment5.target=void\ readItemData(java.util.Scanner)
+numComments=6
--- a/2/PrintedItem.java
+++ b/2/PrintedItem.java
@@ -0,0 +1,64 @@
+
+/**
+ * Write a description of class PrintedItem here.
+ * 
+ * @author (your name) 
+ * @version (a version number or a date)
+ */
+
+import java.util.Scanner;
+import java.util.ArrayList;
+import java.util.NoSuchElementException;
+
+public abstract class PrintedItem extends LibraryItem
+{
+    private int noOfPages;
+    private String publisher;
+    
+    /*
+     * Field Accessor Start
+     */
+    public int getNoOfPages()
+    {
+        return noOfPages;
+    }
+    
+    public String getPublisher()
+    {
+        return publisher;
+    }
+    
+    /*
+     * Field Accessor End
+     * 
+     * Field Mutator Start
+     */
+    
+    public void setNoOfPages( int noOfPages )
+    {
+        this.noOfPages = noOfPages;
+    }
+    
+    public void setPublisher( String publisher )
+    {
+        this.publisher = publisher;
+    }
+    
+    /*
+     * Field Mutator End
+     */
+    public void printDetails()
+    {
+        System.out.println("Page Count: " + noOfPages +
+        "\nPublisher: " + publisher);
+        super.printDetails();
+    }
+    
+    public void readItemData( Scanner detailScanner ){
+        if ( detailScanner != null ) {
+            this.noOfPages = Integer.parseInt( detailScanner.next().trim() );
+            this.publisher = detailScanner.next().trim();
+            super.readItemData( detailScanner );
+        }
+    }
+}
--- a/2/data/items_all.txt
+++ b/2/data/items_all.txt
@@ -0,0 +1,43 @@
+// this is a comment, any lines that start with //
+// (and blank lines) should be ignored
+
+[Book data]
+// data is author, isbn, noOfPages, publisher, title, itemCode, cost, timesBorrowed, onLoan
+Barnes and Kolling, 9780131976290,480, Pearson, Objects First with Java, LM002411,3989,781,true
+Aho Sethi and Ullman, 9780201101942,795, Addison-Wesley, Compilers: Principles Techniques and Tools, LM002711,599,500,FALSE
+Harvey Paul and Jeffrey, 9780130622211,1568, Prentice Hall, C# How to Program, LM002876,4599,45,TRUE
+Muster, 9780072193145,1011, McGraw-Hill, Unix Made Easy: The Basics and Beyond (Made Easy), LM002468,6395,678,TRUE
+Thomee, 9783540331216,370, Springer Verlag, Galerkin Finite Element Methods for Parabolic Problems, LM002153,4554,543,FALSE
+
+[periodical data]
+// data is publicationDate, noOfPages, publisher, title, itemCode, cost, timesBorrowed, onLoan
+25-03-20,70, News International, The Times, LM005447,80,250000,FALSE
+26-03-20,70, News International, The Times, LM005002,80,560562,false
+26-04-20, 70, Associated Newspapers, Daily Mail, LM005177,75,478908,false
+
+[CD data]
+
+// data is artist, noOfTracks, playingTime, title, itemCode, cost, timesBorrowed, onLoan
+
+James Blunt,15,68, Back to Bedlam, LM003604,498,234,true
+Duffy,10,73, Rockferry, LM003553,898,90,false
+Adele,12,19,75, LM003580,798,87,FALSE
+Robert Plant and Alison Krauss,13,72, Raising Sand, LM003750,898,89,tRUE
+Goldfrapp,10,72, Seventh Tree, LM003873,1299,9876,true
+Amy Winehouse,11,70, Back To Black, LM003698,698,8765,false
+Jack Johnson,15,67, Sleep Through The Static, LM003773,898,54,True 
+ Mark Ronson,14,74, Version, LM003365,698,56,true 
+Radiohead,10,75, In Rainbows , LM003771,798,6543,FALSE
+Nick Cave,11,68, Dig!!! Lazarus Dig!!!, LM003751,1199,90,False
+Nickelback,11,72, All the Right Reasons, LM003915,598,32,true
+
+[DVD data]
+
+// data is director, playingTime, title, itemCode, cost, timesBorrowed, onLoan
+Chris Miller,92, Shrek The Third, LM004314,1026,900,TRUE 
+Robert Zemeckis,114, Beowulf , LM004079,900,87,FALSE
+Phyllida Lloyd,118,  Mamma Mia, LM004984,798,566,true
+Joe Wright,130, Atonement, LM004720,1293,66,true
+Andrew Adamson,125, The Chronicles of Narnia: Prince Caspian, LM004178,345,45,FALSE
+
+
--- a/2/data/items_and_user_data.txt
+++ b/2/data/items_and_user_data.txt
@@ -0,0 +1,48 @@
+// this is a comment, any lines that start with //
+// (and blank lines) should be ignored
+
+[Book data]
+// data is author, isbn, noOfPages, publisher, title, itemCode, cost, timesBorrowed, onLoan
+Barnes and Kolling, 9780131976290,480, Pearson, Objects First with Java, LM002411,3989,781,true
+Aho Sethi and Ullman, 9780201101942,795, Addison-Wesley, Compilers: Principles Techniques and Tools, LM002711,599,890,FALSE
+Harvey Paul and Jeffrey, 9780130622211,1568, Prentice Hall, C# How to Program, LM002876,4599,45,TRUE
+Muster, 9780072193145,1011, McGraw-Hill, Unix Made Easy: The Basics and Beyond (Made Easy), LM002468,6395,8765,TRUE
+Thomee, 9783540331216,370, Springer Verlag, Galerkin Finite Element Methods for Parabolic Problems, LM002153,4554,780,FALSE
+
+[CD data]
+
+// data is artist, noOfTracks, playingTime, title, itemCode, cost, timesBorrowed, onLoan
+
+James Blunt,15,68, Back to Bedlam, LM003604,498,234,true
+Duffy,10,73, Rockferry, LM003553,898,90,false
+Adele,12,19,75, LM003580,798,87,FALSE
+Robert Plant and Alison Krauss,13,72, Raising Sand, LM003750,898,89,tRUE
+Goldfrapp,10,72, Seventh Tree, LM003873,1299,9876,true
+Amy Winehouse,11,70, Back To Black, LM003698,698,8765,false
+Jack Johnson,15,67, Sleep Through The Static, LM003773,898,54,True 
+ Mark Ronson,14,74, Version, LM003365,698,56,true 
+Radiohead,10,75, In Rainbows , LM003771,798,6543,FALSE
+Nick Cave,11,68, Dig!!! Lazarus Dig!!!, LM003751,1199,90,False
+Nickelback,11,72, All the Right Reasons, LM003915,598,32,true
+
+[DVD data]
+
+// data is director, playingTime, title, itemCode, cost, timesBorrowed, onLoan
+Chris Miller,92, Shrek The Third, LM004314,1026,900,TRUE 
+Robert Zemeckis,114, Beowulf , LM004079,900,87,FALSE
+Phyllida Lloyd,118,  Mamma Mia, LM004984,798,566,true
+Joe Wright,130, Atonement, LM004720,1293,66,true
+Andrew Adamson,125, The Chronicles of Narnia: Prince Caspian, LM004178,345,45,FALSE
+
+[periodical data]
+// data is publicationDate, noOfPages, publisher, title, itemCode, cost, timesBorrowed, onLoan
+25-03-08,70, News International, The Times, LM005447,80,0,FALSE
+26-03-08,70, News International, The Times, LM005002,80,0,false
+26-03-08,60, Associated Newspapers, Daily Mail, LM005177,40,0,false
+
+[Library User Data]
+// data is userID, surname, firstName, otherInitials, title
+unknown, Newton, David, E, Dr
+unknown, Gregson, Brian, R T, Mr
+unknown, Evans, David, , Dr
+unknown, Smith, Sara, C, Ms
--- a/2/data/library_user_data.txt
+++ b/2/data/library_user_data.txt
@@ -0,0 +1,12 @@
+// this is a comment, any lines that start with //
+// (and blank lines) should be ignored
+
+// New user data
+// data is userID, surname, firstName, otherInitials, title
+
+[Library User Data]
+
+unknown, Newton, David, E, Dr
+unknown, Gregson, Brian, R T, Mr
+unknown, Evans, David, , Dr
+unknown, Smith, Sara, C, Ms
--- a/2/data/testuserwrite.txt
+++ b/2/data/testuserwrite.txt
@@ -0,0 +1,4 @@
+unknown, Newton, David, E, Dr
+unknown, Gregson, Brian, R T, Mr
+unknown, Evans, David, , Dr
+unknown, Smith, Sara, C, Ms
--- a/2/doc/Book.html
+++ b/2/doc/Book.html
@@ -0,0 +1,183 @@
+<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">
+<!--NewPage-->
+<HTML>
+<HEAD>
+<!-- Generated by javadoc (build 1.8.0_392) on Thu Feb 29 11:54:14 GMT 2024 -->
+<META http-equiv="Content-Type" content="text/html; charset=UTF-8">
+<TITLE>
+Book
+</TITLE>
+
+<META NAME="date" CONTENT="2024-02-29">
+
+<LINK REL ="stylesheet" TYPE="text/css" HREF="stylesheet.css" TITLE="Style">
+
+<SCRIPT type="text/javascript">
+function windowTitle()
+{
+    if (location.href.indexOf('is-external=true') == -1) {
+        parent.document.title="Book";
+    }
+}
+</SCRIPT>
+<NOSCRIPT>
+</NOSCRIPT>
+
+</HEAD>
+
+<BODY BGCOLOR="white" onload="windowTitle();">
+<HR>
+
+<HR>
+<!-- ======== START OF CLASS DATA ======== -->
+<H2>
+Class Book</H2>
+<PRE>
+java.lang.Object
+  <IMG SRC="./resources/inherit.gif" ALT="extended by ">LibraryItem
+      <IMG SRC="./resources/inherit.gif" ALT="extended by ">PrintedItem
+          <IMG SRC="./resources/inherit.gif" ALT="extended by "><B>Book</B>
+</PRE>
+<HR>
+<DL>
+<DT><PRE>public class <B>Book</B><DT>extends PrintedItem</DL>
+</PRE>
+
+<P>
+<HR>
+
+<P>
+
+<!-- ======== CONSTRUCTOR SUMMARY ======== -->
+
+<A NAME="constructor_summary"><!-- --></A>
+<TABLE BORDER="1" WIDTH="100%" CELLPADDING="3" CELLSPACING="0" SUMMARY="">
+<TR BGCOLOR="#CCCCFF" CLASS="TableHeadingColor">
+<TH ALIGN="left" COLSPAN="2"><FONT SIZE="+2">
+<B>Constructor Summary</B></FONT></TH>
+</TR>
+<TR BGCOLOR="white" CLASS="TableRowColor">
+<TD><CODE><B><A HREF="Book.html#Book()">Book</A></B>()</CODE>
+
+<BR>
+&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;Constructor for objects of class Book</TD>
+</TR>
+</TABLE>
+&nbsp;
+<!-- ========== METHOD SUMMARY =========== -->
+
+<A NAME="method_summary"><!-- --></A>
+<TABLE BORDER="1" WIDTH="100%" CELLPADDING="3" CELLSPACING="0" SUMMARY="">
+<TR BGCOLOR="#CCCCFF" CLASS="TableHeadingColor">
+<TH ALIGN="left" COLSPAN="2"><FONT SIZE="+2">
+<B>Method Summary</B></FONT></TH>
+</TR>
+<TR BGCOLOR="white" CLASS="TableRowColor">
+<TD ALIGN="right" VALIGN="top" WIDTH="1%"><FONT SIZE="-1">
+<CODE>&nbsp;void</CODE></FONT></TD>
+<TD><CODE><B><A HREF="Book.html#printDetails()">printDetails</A></B>()</CODE>
+
+<BR>
+&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;</TD>
+</TR>
+<TR BGCOLOR="white" CLASS="TableRowColor">
+<TD ALIGN="right" VALIGN="top" WIDTH="1%"><FONT SIZE="-1">
+<CODE>&nbsp;void</CODE></FONT></TD>
+<TD><CODE><B><A HREF="Book.html#readItemData(java.util.Scanner)">readItemData</A></B>(java.util.Scanner&nbsp;detailScanner)</CODE>
+
+<BR>
+&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;</TD>
+</TR>
+</TABLE>
+&nbsp;<A NAME="methods_inherited_from_class_PrintedItem"><!-- --></A>
+<TABLE BORDER="1" WIDTH="100%" CELLPADDING="3" CELLSPACING="0" SUMMARY="">
+<TR BGCOLOR="#EEEEFF" CLASS="TableSubHeadingColor">
+<TH ALIGN="left"><B>Methods inherited from class PrintedItem</B></TH>
+</TR>
+<TR BGCOLOR="white" CLASS="TableRowColor">
+<TD><CODE>getNoOfPages, getPublisher, setNoOfPages, setPublisher</CODE></TD>
+</TR>
+</TABLE>
+&nbsp;<A NAME="methods_inherited_from_class_LibraryItem"><!-- --></A>
+<TABLE BORDER="1" WIDTH="100%" CELLPADDING="3" CELLSPACING="0" SUMMARY="">
+<TR BGCOLOR="#EEEEFF" CLASS="TableSubHeadingColor">
+<TH ALIGN="left"><B>Methods inherited from class LibraryItem</B></TH>
+</TR>
+<TR BGCOLOR="white" CLASS="TableRowColor">
+<TD><CODE>getCost, getItemCode, getOnLoan, getTimesBorrowed, getTitle, setCost, setItemCode, setOnLoan, setTimesBorrowed, setTitle</CODE></TD>
+</TR>
+</TABLE>
+&nbsp;<A NAME="methods_inherited_from_class_java.lang.Object"><!-- --></A>
+<TABLE BORDER="1" WIDTH="100%" CELLPADDING="3" CELLSPACING="0" SUMMARY="">
+<TR BGCOLOR="#EEEEFF" CLASS="TableSubHeadingColor">
+<TH ALIGN="left"><B>Methods inherited from class java.lang.Object</B></TH>
+</TR>
+<TR BGCOLOR="white" CLASS="TableRowColor">
+<TD><CODE>clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait</CODE></TD>
+</TR>
+</TABLE>
+&nbsp;
+<P>
+
+<!-- ========= CONSTRUCTOR DETAIL ======== -->
+
+<A NAME="constructor_detail"><!-- --></A>
+<TABLE BORDER="1" WIDTH="100%" CELLPADDING="3" CELLSPACING="0" SUMMARY="">
+<TR BGCOLOR="#CCCCFF" CLASS="TableHeadingColor">
+<TH ALIGN="left" COLSPAN="1"><FONT SIZE="+2">
+<B>Constructor Detail</B></FONT></TH>
+</TR>
+</TABLE>
+
+<A NAME="Book()"><!-- --></A><H3>
+Book</H3>
+<PRE>
+public <B>Book</B>()</PRE>
+<DL>
+<DD>Constructor for objects of class Book
+<P>
+</DL>
+
+<!-- ============ METHOD DETAIL ========== -->
+
+<A NAME="method_detail"><!-- --></A>
+<TABLE BORDER="1" WIDTH="100%" CELLPADDING="3" CELLSPACING="0" SUMMARY="">
+<TR BGCOLOR="#CCCCFF" CLASS="TableHeadingColor">
+<TH ALIGN="left" COLSPAN="1"><FONT SIZE="+2">
+<B>Method Detail</B></FONT></TH>
+</TR>
+</TABLE>
+
+<A NAME="printDetails()"><!-- --></A><H3>
+printDetails</H3>
+<PRE>
+public void <B>printDetails</B>()</PRE>
+<DL>
+<DD><DL>
+<DT><B>Overrides:</B><DD><CODE>printDetails</CODE> in class <CODE>LibraryItem</CODE></DL>
+</DD>
+<DD><DL>
+</DL>
+</DD>
+</DL>
+<HR>
+
+<A NAME="readItemData(java.util.Scanner)"><!-- --></A><H3>
+readItemData</H3>
+<PRE>
+public void <B>readItemData</B>(java.util.Scanner&nbsp;detailScanner)</PRE>
+<DL>
+<DD><DL>
+<DT><B>Overrides:</B><DD><CODE>readItemData</CODE> in class <CODE>PrintedItem</CODE></DL>
+</DD>
+<DD><DL>
+</DL>
+</DD>
+</DL>
+<!-- ========= END OF CLASS DATA ========= -->
+<HR>
+
+<HR>
+
+</BODY>
+</HTML>
--- a/2/doc/allclasses-frame.html
+++ b/2/doc/allclasses-frame.html
@@ -2,13 +2,13 @@
 <!--NewPage-->
 <HTML>
 <HEAD>
-<!-- Generated by javadoc (build 1.8.0_392) on Fri Feb 16 14:05:04 GMT 2024 -->
+<!-- Generated by javadoc (build 1.8.0_392) on Thu Feb 29 11:54:14 GMT 2024 -->
 <META http-equiv="Content-Type" content="text/html; charset=UTF-8">
 <TITLE>
 All Classes
 </TITLE>

-<META NAME="date" CONTENT="2024-02-16">
+<META NAME="date" CONTENT="2024-02-29">

 <LINK REL ="stylesheet" TYPE="text/css" HREF="stylesheet.css" TITLE="Style">

@@ -22,7 +22,7 @@ All Classes

 <TABLE BORDER="0" WIDTH="100%" SUMMARY="">
 <TR>
-<TD NOWRAP><FONT CLASS="FrameItemFont"><A HREF="LibraryItem.html" title="class in &lt;Unnamed&gt;" target="classFrame">LibraryItem</A>
+<TD NOWRAP><FONT CLASS="FrameItemFont"><A HREF="Book.html" title="class in &lt;Unnamed&gt;" target="classFrame">Book</A>
 <BR>
 </FONT></TD>
 </TR>
--- a/2/doc/allclasses-noframe.html
+++ b/2/doc/allclasses-noframe.html
@@ -2,13 +2,13 @@
 <!--NewPage-->
 <HTML>
 <HEAD>
-<!-- Generated by javadoc (build 1.8.0_392) on Fri Feb 16 14:05:04 GMT 2024 -->
+<!-- Generated by javadoc (build 1.8.0_392) on Thu Feb 29 11:54:14 GMT 2024 -->
 <META http-equiv="Content-Type" content="text/html; charset=UTF-8">
 <TITLE>
 All Classes
 </TITLE>

-<META NAME="date" CONTENT="2024-02-16">
+<META NAME="date" CONTENT="2024-02-29">

 <LINK REL ="stylesheet" TYPE="text/css" HREF="stylesheet.css" TITLE="Style">

@@ -22,7 +22,7 @@ All Classes

 <TABLE BORDER="0" WIDTH="100%" SUMMARY="">
 <TR>
-<TD NOWRAP><FONT CLASS="FrameItemFont"><A HREF="LibraryItem.html" title="class in &lt;Unnamed&gt;">LibraryItem</A>
+<TD NOWRAP><FONT CLASS="FrameItemFont"><A HREF="Book.html" title="class in &lt;Unnamed&gt;">Book</A>
 <BR>
 </FONT></TD>
 </TR>
--- a/2/doc/constant-values.html
+++ b/2/doc/constant-values.html
@@ -2,13 +2,13 @@
 <!--NewPage-->
 <HTML>
 <HEAD>
-<!-- Generated by javadoc (build 1.8.0_392) on Fri Feb 16 14:05:04 GMT 2024 -->
+<!-- Generated by javadoc (build 1.8.0_392) on Thu Feb 29 11:54:14 GMT 2024 -->
 <META http-equiv="Content-Type" content="text/html; charset=UTF-8">
 <TITLE>
 Constant Field Values
 </TITLE>

-<META NAME="date" CONTENT="2024-02-16">
+<META NAME="date" CONTENT="2024-02-29">

 <LINK REL ="stylesheet" TYPE="text/css" HREF="stylesheet.css" TITLE="Style">

--- a/2/doc/index.html
+++ b/2/doc/index.html
@@ -2,7 +2,7 @@
 <!--NewPage-->
 <HTML>
 <HEAD>
-<!-- Generated by javadoc on Fri Feb 16 14:05:04 GMT 2024-->
+<!-- Generated by javadoc on Thu Feb 29 11:54:14 GMT 2024-->
 <META http-equiv="Content-Type" content="text/html; charset=UTF-8">
 <TITLE>
 Generated Documentation (Untitled)
@@ -23,7 +23,7 @@ Generated Documentation (Untitled)
 </HEAD>
 <FRAMESET cols="20%,80%" title="" onLoad="top.loadFrames()">
 <FRAME src="allclasses-frame.html" name="packageFrame" title="All classes and interfaces (except non-static nested types)">
-<FRAME src="LibraryItem.html" name="classFrame" title="Package, class and interface descriptions" scrolling="yes">
+<FRAME src="Book.html" name="classFrame" title="Package, class and interface descriptions" scrolling="yes">
 <NOFRAMES>
 <H2>
 Frame Alert</H2>
@@ -31,7 +31,7 @@ Frame Alert</H2>
 <P>
 This document is designed to be viewed using the frames feature. If you see this message, you are using a non-frame-capable web client.
 <BR>
-Link to<A HREF="LibraryItem.html">Non-frame version.</A>
+Link to<A HREF="Book.html">Non-frame version.</A>
 </NOFRAMES>
 </FRAMESET>
 </HTML>
--- a/2/doc/logfile.txt
+++ b/2/doc/logfile.txt
@@ -23,13 +23,13 @@ UTF-8
 /usr/share/bluej/bjdoclet.jar
 -doclet
 bluej.doclet.doclets.formats.html.HtmlDoclet
-/home/boris/OneDrive/Computer Science Year 1/Semester 2/Programming 2/Project/Part 2/LibraryItem.java
+/home/boris/OneDrive/Computer Science Year 1/Semester 2/Programming 2/Project/Part 2/Book.java
 <---- end of javadoc command ---->
-Loading source file /home/boris/OneDrive/Computer Science Year 1/Semester 2/Programming 2/Project/Part 2/LibraryItem.java...
+Loading source file /home/boris/OneDrive/Computer Science Year 1/Semester 2/Programming 2/Project/Part 2/Book.java...
 Constructing Javadoc information...
 Standard Doclet version 1.8.0_392
 Building tree for all the packages and classes...
-Generating /home/boris/OneDrive/Computer Science Year 1/Semester 2/Programming 2/Project/Part 2/doc/LibraryItem.html...
+Generating /home/boris/OneDrive/Computer Science Year 1/Semester 2/Programming 2/Project/Part 2/doc/Book.html...
 Generating /home/boris/OneDrive/Computer Science Year 1/Semester 2/Programming 2/Project/Part 2/doc/package-frame.html...
 Generating /home/boris/OneDrive/Computer Science Year 1/Semester 2/Programming 2/Project/Part 2/doc/package-summary.html...
 Generating /home/boris/OneDrive/Computer Science Year 1/Semester 2/Programming 2/Project/Part 2/doc/constant-values.html...
--- a/2/doc/package-frame.html
+++ b/2/doc/package-frame.html
@@ -2,13 +2,13 @@
 <!--NewPage-->
 <HTML>
 <HEAD>
-<!-- Generated by javadoc (build 1.8.0_392) on Fri Feb 16 14:05:04 GMT 2024 -->
+<!-- Generated by javadoc (build 1.8.0_392) on Thu Feb 29 11:54:14 GMT 2024 -->
 <META http-equiv="Content-Type" content="text/html; charset=UTF-8">
 <TITLE>
 &lt;Unnamed&gt;
 </TITLE>

-<META NAME="date" CONTENT="2024-02-16">
+<META NAME="date" CONTENT="2024-02-29">

 <LINK REL ="stylesheet" TYPE="text/css" HREF="stylesheet.css" TITLE="Style">

@@ -24,7 +24,7 @@
 Classes</FONT>&nbsp;
 <FONT CLASS="FrameItemFont">
 <BR>
-<A HREF="LibraryItem.html" title="class in &lt;Unnamed&gt;" target="classFrame">LibraryItem</A></FONT></TD>
+<A HREF="Book.html" title="class in &lt;Unnamed&gt;" target="classFrame">Book</A></FONT></TD>
 </TR>
 </TABLE>

--- a/2/doc/package-summary.html
+++ b/2/doc/package-summary.html
@@ -2,13 +2,13 @@
 <!--NewPage-->
 <HTML>
 <HEAD>
-<!-- Generated by javadoc (build 1.8.0_392) on Fri Feb 16 14:05:04 GMT 2024 -->
+<!-- Generated by javadoc (build 1.8.0_392) on Thu Feb 29 11:54:14 GMT 2024 -->
 <META http-equiv="Content-Type" content="text/html; charset=UTF-8">
 <TITLE>

 </TITLE>

-<META NAME="date" CONTENT="2024-02-16">
+<META NAME="date" CONTENT="2024-02-29">

 <LINK REL ="stylesheet" TYPE="text/css" HREF="stylesheet.css" TITLE="Style">

@@ -29,7 +29,7 @@ Package &lt;Unnamed&gt;
 <B>Class Summary</B></FONT></TH>
 </TR>
 <TR BGCOLOR="white" CLASS="TableRowColor">
-<TD WIDTH="15%"><B><A HREF="LibraryItem.html" title="class in &lt;Unnamed&gt;">LibraryItem</A></B></TD>
+<TD WIDTH="15%"><B><A HREF="Book.html" title="class in &lt;Unnamed&gt;">Book</A></B></TD>
 <TD>&nbsp;</TD>
 </TR>
 </TABLE>
--- a/2/Project/Part
+++ b/2/Project/Part
--- a/2/package.bluej
+++ b/2/package.bluej
@@ -8,66 +8,140 @@ dependency2.type=UsesDependency
 dependency3.from=Library
 dependency3.to=LibraryItem
 dependency3.type=UsesDependency
+dependency4.from=Library
+dependency4.to=CD
+dependency4.type=UsesDependency
+dependency5.from=Library
+dependency5.to=DVD
+dependency5.type=UsesDependency
+dependency6.from=Library
+dependency6.to=LibraryUser
+dependency6.type=UsesDependency
 objectbench.height=76
-objectbench.width=1900
+objectbench.width=940
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-target1.editor.y=52
-target1.height=60
-target1.name=LibraryItem
+target1.editor.x=1017
+target1.editor.y=76
+target1.height=50
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+target4.name=DVD
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--- a/20240227171626.png
+++ b/20240227171626.png
--- a/20240227171700.png
+++ b/20240227171700.png
--- a/20240227171728.png
+++ b/20240227171728.png