vault backup: 2024-03-08 10:55:57

.obsidian/workspace.json

@@ -42,8 +42,19 @@
                 "file": "Semester 2/Database Systems/Booklet of Lecture Slides for Semester Two (2).pdf"
               }
             }
+          },
+          {
+            "id": "bde983126ec4558f",
+            "type": "leaf",
+            "state": {
+              "type": "pdf",
+              "state": {
+                "file": "Semester 2/Database Systems/Exercise Booklet.pdf"
+              }
+            }
           }
-        ]
+        ],
+        "currentTab": 1
       }
     ],
     "direction": "vertical"
@@ -192,6 +203,15 @@
   },
   "active": "e96e468fb0a709e5",
   "lastOpenFiles": [
+    "images/Pasted image 20240308103937.png",
+    "images/Pasted image 20240308103720.png",
+    "images/Pasted image 20240308102031.png",
+    "images/Pasted image 20240308101739.png",
+    "Semester 2/Programming 2/Project/Part 2/Library.java#",
+    "Semester 2/Database Systems/Exercise Booklet.pdf",
+    "Semester 2/Database Systems/Week 8/Week 8 Database Systems.md",
+    "Semester 2/Database Systems/Week 7/Week 7 Database Systems.md",
+    "Semester 2/Database Systems/Booklet of Lecture Slides for Semester Two (2).pdf",
     "images/Pasted image 20240305135229.png",
     "images/Pasted image 20240305135043.png",
     "images/Pasted image 20240305134944.png",
@@ -199,8 +219,6 @@
     "images/Pasted image 20240305134835.png",
     "images/Pasted image 20240305134734.png",
     "images/Pasted image 20240305134506.png",
-    "Semester 2/Database Systems/Booklet of Lecture Slides for Semester Two (2).pdf",
-    "Semester 2/Database Systems/Week 8/Week 8 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#",
@@ -208,13 +226,6 @@
     "Semester 2/Programming 2/Project/Part 2/CD.java#",
     "Semester 2/Programming 2/Project/Part 2/DVD.java#",
     "Semester 2/Programming 2/Project/Part 2/AudioVisual.java#",
-    "Semester 2/Programming 2/Project/Part 2/PrintedItem.java#",
-    "Semester 2/Programming 2/Project/Part 2/Library.java#",
-    "images/Pasted image 20240305131110.png",
-    "images/Pasted image 20240305130824.png",
-    "Semester 2/Database Systems/Week 7/Week 7 Database Systems.md",
-    "images/Pasted image 20240227171728.png",
-    "images/Pasted image 20240227171700.png",
     "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",
     "Semester 2/Programming 2/Assessment 3 Revision/Parameter Passing WS3.md",

Semester 2/Database Systems/Week 8/Week 8 Database Systems.md

@@ -55,7 +55,7 @@ Definition: Checkpoints are points of sync between database and log file. All bu
 	- Checkpoint record to log file which contains identities of transactions active at time of checkpoint
 2. Resume processing.
 
-![](Pasted%20image%2020240305134734.png)
+- ![](Pasted%20image%2020240305134734.png)
 
 ### Example 1 ( Immediate )
 
@@ -88,3 +88,55 @@ Definition: Checkpoints are points of sync between database and log file. All bu
 
 ## Example of Log Use ( Immediate )
 ![](Pasted%20image%2020240305135229.png)
+
+# Shadow Paging
+
+Alternative technique for providing atomicity and durability.
+DBMS maintains two page tables during the life of a transaction.
+1. Current Page
+2. Shadow Page Table
+
+**Transaction Start**: Two pages are the same
+- Shadow page table is never changed, only used to restore database.
+**Transaction Execution**: current page table records all updates to database
+**Transaction End**: Current page table becomes shadow page table and all modified pages from database buffers written to secondary storage.
+**Transaction Failure**: new pages ignored, shadow page table becomes current page table.
+
+# Tutorial
+
+1. State whether each of the following is true or false. If it is false then briefly explain why.
+	1. True
+	2. True
+	3. True
+	4. False: REDO / NO UNDO
+	5. True
+2. The DBMS maintains a log file containing transaction records that identify the start and end of transactions and the before and after images of the write operations. Consider the log files shown in Tables 32.1 and 32.2. For each one, explain what the DBMS recovery system would do, and why, if there was a failure at the time shown below each table and the DBMS was using:
+	1. Deferred update protocol
+		1. 32.1 Fail @10:24
+			- Redo T1 as commit before failure. Ignore T2 and 3, active at point of failure. T4 not active at point of failure, Ignore.
+		2. 32.2 Fail @9.21
+			- Redo T2 and 4, since no commit occurs. T3 commits after the checkpoint, and anything before has no effect.
+	1. Immediate update protocol
+		1. 32.1 Fail @10.24
+			- Undo T2 and 3, since they are active, and do not commit. T1 must be redone, and T4 is ignored, as it never started.
+		2. 32.2 Fail @9:21
+			- Undo T2 and 4, since they are active and do not commit. Redo T3, as it is active after the checkpoint.
+
+# Workshop
+
+1. ![](Pasted%20image%2020240308101739.png)
+2. ![](Pasted%20image%2020240308102031.png)
+3. ![](Pasted%20image%2020240308103720.png)
+```
+SELECT SUM([UnitPrice]) AS TotalPrice
+FROM [Products] 
+WHERE [SupplierID] = (
+	SELECT [SupplierID] 
+	FROM [Suppliers]
+	WHERE [Country] = 'UK'
+	);
+	
+```
+
+4. ![](Pasted%20image%2020240308103937.png)
+	1. 

Semester 2/Programming 2/Project/Part 2/DateUtil.ctxt

@@ -0,0 +1,26 @@
+#BlueJ class context
+comment0.params=date
+comment0.target=java.lang.String\ convertDateToLongString(java.util.Date)
+comment0.text=\n\ Converts\ a\ Date\ object\ to\ a\ corresponding\ String\ in\n\ the\ long\ date\ pattern\ style\ "Saturday,\ 25\ March\ 2023".\n\n\ @param\ \ \ \ \ date\ \ a\ Date\ object\n\n\ @return\ \ \ \ a\ String,\ containing\ a\ long\ date\ pattern\n
+comment1.params=date
+comment1.target=java.lang.String\ convertDateToShortString(java.util.Date)
+comment1.text=\n\ Converts\ a\ Date\ object\ to\ a\ corresponding\ String\ in\n\ the\ short\ date\ pattern\ style\ "25-03-2023".\n\n\ @param\ \ \ \ \ date\ \ a\ Date\ object\n\n\ @return\ \ \ \ a\ String,\ containing\ a\ short\ date\ pattern\n
+comment2.params=dateString
+comment2.target=java.util.Date\ convertStringToDate(java.lang.String)
+comment2.text=\n\ Converts\ a\ string\ in\ the\ short\ date\ pattern\ style\ "25-03-2023"\n\ to\ a\ corresponding\ Date\ object.\n\n\ Any\ leading\ or\ trailing\ spaces\ are\ first\ removed\ from\ the\ date\ string.\n\ The\ String\ parameter\ that\ represent\ a\ date\ as\ a\ string\ must\ be\ in\ the\n\ format\ dd-mm-yyy\ (e.g.\ 25-03-2023\ or\ 25-3-2023)\ where\ dd\ represents\n\ one\ or\ two\ digits\ representing\ the\ day\ in\ the\ month,\ similarly\ for\n\ mm\ representing\ the\ month\ in\ the\ year\ and\ yyyy\ represents\ the\ four\n\ digits\ for\ the\ year.\n\n\ A\ RuntimeException\ is\ thrown\ if\ the\ date\ string\ is\ not\ recognised\ as\n\ a\ valid\ date.\ Such\ exceptions\ do\ not\ need\ to\ be\ caught\ or\ thrown\ as\ \n\ they\ are\ unchecked\ exceptions,\ but\ can\ be\ caught\ if\ necessary.\n\n\ @param\ \ \ \ \ dateString\ \ a\ Date\ object\n\n\ @return\ \ \ \ the\ Date\ object\n
+comment3.params=startDate\ endDate
+comment3.target=int\ daysBetween(java.util.Date,\ java.util.Date)
+comment3.text=\n\ Calculates\ the\ number\ of\ days\ between\ two\ given\ dates,\ startDate\ and\ endDate.\n\n\ If\ startDate\ is\ after\ endDate\ then\ the\ number\ of\ days\ returned\ will\ be\ negative.\n\n\ @param\ \ \ \ \ startDate\ \ \ a\ Date\ object\n\ @param\ \ \ \ \ endDate\ \ \ \ \ a\ Date\ object\n\n\ @return\ \ \ \ an\ int,\ number\ of\ days\ between\ the\ dates\n
+comment4.params=date\ noOfDays
+comment4.target=java.util.Date\ incrementDate(java.util.Date,\ int)
+comment4.text=\n\ Given\ date,\ a\ Date\ object,\ and\ noOfDays,\ an\ int,\ the\ method\ returns\n\ a\ Date\ object\ corresponding\ to\ noOfDays\ later\ than\ date.\n\n\ If\ noOfDays\ is\ negative,\ the\ resulting\ Date\ object\ will\ be\ before\ date.\n\n\ @param\ \ \ \ \ date\ \ \ \ \ \ a\ Date\ object\n\ @param\ \ \ \ \ noOfDays\ \ an\ int\n\n\ @return\ \ \ \ a\ Date\n
+comment5.params=year
+comment5.target=boolean\ isLeapYear(int)
+comment5.text=\n\ Given\ year,\ an\ int,\ the\ method\ checks\ to\ see\ if\ the\ year\n\ is\ a\ leap\ year.\n\n\ @param\ \ \ \ \ year,\ \ an\ int\n\n\ @return\ \ \ \ a\ boolean,\ true\ only\ if\ the\ year\ is\ a\ leap\ year.\n
+comment6.params=dateString
+comment6.target=boolean\ isValidDateString(java.lang.String)
+comment6.text=\n\ Given\ dateString,\ a\ String,\ the\ method\ checks\ to\ see\ if\ string\n\ corresponds\ to\ a\ valid\ shortDatePattern.\ \n\n\ @param\ \ \ \ \ dateString,\ a\ String\n\n\ @return\ \ \ \ a\ boolean,\ true\ only\ if\ the\ dateString\ is\ a\ valid\ pattern\n
+comment7.params=date
+comment7.target=java.util.Date\ nextDate(java.util.Date)
+comment7.text=\n\ Given\ date,\ a\ Date\ object,\ the\ method\ returns\n\ a\ Date\ object\ corresponding\ to\ the\ next\ day.\n\n\ @param\ \ \ \ \ noOfDays\ \ an\ int\n\n\ @return\ \ \ \ a\ Date\n
+numComments=8

Semester 2/Programming 2/Project/Part 2/DateUtil.java

@@ -0,0 +1,263 @@
+import java.text.SimpleDateFormat;
+import java.text.ParseException;
+import java.text.ParsePosition;
+import java.util.Date;
+import java.util.Calendar;
+import java.util.GregorianCalendar;
+/**
+ *
+ * A class DateUtil with the following methods for dealing with dates.
+ *
+ *    public static String  convertDateToLongString(Date date)
+ *    public static String  convertDateToShortString(Date date)
+ *    public static Date    convertStringToDate(String dateString)
+ *    public static int     daysBetween(Date startDate, Date endDate)
+ *    public static Date    incrementDate(Date date, int noOfDays)
+ *    public static boolean isLeapYear(int year)
+ *    public static boolean isValidDateString(String dateString)
+ *    public static Date    nextDate(Date date)
+ *
+ * @author D E Newton
+ *
+ */
+
+public class DateUtil
+{
+   public static SimpleDateFormat dateFormatter;
+   private static String longDatePattern;
+   private static String shortDatePattern;
+
+   /**
+    *    initializer block -- useful for
+    *    initializing static fields
+    */
+   static
+   {
+      shortDatePattern = "dd-MM-yyyy";       // dd = day, MM = month, yyyy = year (as 2, 2 and 4 digits respectively)
+      longDatePattern = "EEEE, d MMMM yyyy"; // e.g. Saturday, 25 March 2023
+                                             // EEEE (4 or more) = day in week, in full e.g.Saturday
+                                             // MMMMM (4 or more) = month name as text in full e.g. March
+                                             // d = day as 1 or 2 digits e.g. 25th of month -> 25, 23rd -> 23
+                                             //
+                                             // some alternatives below to help understanding (see documentation for SimpleDateFormat class)
+                                             // EE (3 or less) -> Tue
+                                             // MMMM              = month name as text in short e.g. Oct
+                                             // M (or MM)         = month as digits e.g.  1 (or 01) would correspond to January
+      dateFormatter = new SimpleDateFormat(shortDatePattern); // default pattern set
+      dateFormatter.setLenient(false); // default is true and impossible dates such
+                                       // as 31-09-2023 would be accepted but interpreted as 01-10-2023
+   }
+
+   /**
+    * Converts a Date object to a corresponding String in
+    * the long date pattern style "Saturday, 25 March 2023".
+    *
+    * @param     date  a Date object
+    *
+    * @return    a String, containing a long date pattern
+    */
+   public static String convertDateToLongString(Date date)
+   {
+      dateFormatter.applyPattern(longDatePattern);
+      String dateString = dateFormatter.format(date);
+      dateFormatter.applyPattern(shortDatePattern);  // reset pattern
+      return dateString;
+   }
+
+   /**
+    * Converts a Date object to a corresponding String in
+    * the short date pattern style "25-03-2023".
+    *
+    * @param     date  a Date object
+    *
+    * @return    a String, containing a short date pattern
+    */
+   public static String convertDateToShortString(Date date)
+   {
+      return dateFormatter.format(date);
+   }
+
+   /**
+    * Converts a string in the short date pattern style "25-03-2023"
+    * to a corresponding Date object.
+    *
+    * Any leading or trailing spaces are first removed from the date string.
+    * The String parameter that represent a date as a string must be in the
+    * format dd-mm-yyy (e.g. 25-03-2023 or 25-3-2023) where dd represents
+    * one or two digits representing the day in the month, similarly for
+    * mm representing the month in the year and yyyy represents the four
+    * digits for the year.
+    *
+    * A RuntimeException is thrown if the date string is not recognised as
+    * a valid date. Such exceptions do not need to be caught or thrown as 
+    * they are unchecked exceptions, but can be caught if necessary.
+    *
+    * @param     dateString  a Date object
+    *
+    * @return    the Date object
+    */
+   public static Date convertStringToDate(String dateString)
+   {
+      dateString = dateString.trim();
+
+      ParsePosition posn = new ParsePosition(0);  // initialise posn to the beginning of the string to be parsed
+
+      Date date = dateFormatter.parse(dateString, posn);
+      int endIndex = posn.getIndex(); // posn after parsing
+
+      String message = "Date string <" + dateString + "> not recognised";
+      if( date==null )
+      {
+         // parsing failed because string not recognised
+         message += ".";
+         throw new RuntimeException(message);
+      }
+      else if( endIndex!=dateString.length() )
+      {
+         // parsing failed because parsing did not "consume" all the characters
+         // in the string, indicating the complete string was not recognised
+         message += " because it contains extra characters after a date.";
+         throw new RuntimeException(message);
+      }
+      else
+         return date;
+   }
+
+   /**
+    * Calculates the number of days between two given dates, startDate and endDate.
+    *
+    * If startDate is after endDate then the number of days returned will be negative.
+    *
+    * @param     startDate   a Date object
+    * @param     endDate     a Date object
+    *
+    * @return    an int, number of days between the dates
+    */
+   public static int daysBetween(Date startDate, Date endDate)
+   {
+      // first check that startDate is not after endDate
+      boolean outOfOrder;
+      Date temp;
+
+      if( startDate.compareTo(endDate)<=0 )
+      {
+         outOfOrder = false;
+      }
+      else
+      {
+         outOfOrder = true;
+         temp = startDate;
+         startDate = endDate;
+         endDate = temp;
+      }
+
+      int daysBetween = 0;
+
+      Calendar calendar = new GregorianCalendar();
+      calendar.setTime(startDate);  // initialised at start date
+
+      Calendar calendarEndDate = new GregorianCalendar();
+      calendarEndDate.setTime(endDate);
+
+      // First advance calendar a year at a time without advancing past the end date.
+      // This is much quicker, for dates that are years apart, than simply relying  on the
+      // later "day at a time" loop. Advancing "a month at a time" before the "day at a
+      // time" loop would be even better but complex because of the varying month lengths.
+
+      Calendar prevYearCalendar = (Calendar) calendar.clone();
+      calendar.add(Calendar.YEAR, 1);
+      // advance calendar a year at a time until end date reached
+      while( !calendar.getTime().after(endDate) )
+      {
+         if( isLeapYear(prevYearCalendar.get(Calendar.YEAR)) &&
+             prevYearCalendar.get(Calendar.MONTH)<Calendar.MARCH )
+            // advancing past a leap year day
+            daysBetween += 366;
+         else
+            daysBetween += 365;
+
+         prevYearCalendar = (Calendar) calendar.clone();
+         calendar.add(Calendar.YEAR, 1);
+      }
+      calendar = prevYearCalendar; // calendar always advances too far, so need to correct
+
+      // now advance calendar a day at a time until end date reached
+      while( calendar.getTime().before(endDate) )
+      {
+         calendar.add(Calendar.DAY_OF_MONTH, 1);
+         daysBetween++;
+      }
+
+      if( outOfOrder )
+         daysBetween = -daysBetween;
+
+      return daysBetween;
+   }
+
+   /**
+    * Given date, a Date object, and noOfDays, an int, the method returns
+    * a Date object corresponding to noOfDays later than date.
+    *
+    * If noOfDays is negative, the resulting Date object will be before date.
+    *
+    * @param     date      a Date object
+    * @param     noOfDays  an int
+    *
+    * @return    a Date
+    */
+   public static Date incrementDate(Date date, int noOfDays)
+   {
+      Calendar calendar = new GregorianCalendar();
+      calendar.setTime(date);
+      calendar.add(Calendar.DAY_OF_MONTH, noOfDays);
+      return  calendar.getTime();
+   }
+
+   /**
+    * Given year, an int, the method checks to see if the year
+    * is a leap year.
+    *
+    * @param     year,  an int
+    *
+    * @return    a boolean, true only if the year is a leap year.
+    */
+   public static boolean isLeapYear(int year)
+   {
+      GregorianCalendar calendar = new GregorianCalendar();
+      return calendar.isLeapYear(year);
+   }
+
+   /**
+    * Given dateString, a String, the method checks to see if string
+    * corresponds to a valid shortDatePattern. 
+    *
+    * @param     dateString, a String
+    *
+    * @return    a boolean, true only if the dateString is a valid pattern
+    */
+   public static boolean isValidDateString(String dateString)
+   {
+      try
+      {
+         Date d = DateUtil.convertStringToDate(dateString);
+         return true;
+      }
+      catch(RuntimeException ex)
+      {
+         return false;
+      }      
+   }
+   
+   /**
+    * Given date, a Date object, the method returns
+    * a Date object corresponding to the next day.
+    *
+    * @param     noOfDays  an int
+    *
+    * @return    a Date
+    */
+   public static Date nextDate(Date date)
+   {
+      return incrementDate(date, 1);
+   }
+}

Semester 2/Programming 2/Project/Part 2/Library.ctxt

@@ -4,20 +4,23 @@ comment0.target=Library()
 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
+comment1.text=\n\ Inserts\ object\ value\ item\ alongside\ key\ of\ @itemCode\ into\ @itemsMap.\n
 comment2.params=user
 comment2.target=void\ storeUser(LibraryUser)
-comment2.text=\n\ Appends\ a\ LibraryUser\ to\ the\ userList.\n
+comment2.text=\n\ Inserts\ object\ value\ user\ alongside\ key\ of\ @userID\ into\ @customerMap.\n\ If\ the\ userID\ is\ set\ to\ unknown,\ it\ will\ call\ @generateUserID.\n
-comment3.params=prefix\ length
+comment3.params=reservation
-comment3.target=java.lang.String\ generateUserID(java.lang.String,\ int)
+comment3.target=void\ storeLibraryReservation(LibraryReservation)
-comment3.text=\n\ Returns\ a\ random\ unique\ user\ ID\ by\ specifying\ \n\ @prefix\ -\ arbitrary\ alphanumeric\ prefix\n\ @length\ -\ length\ of\ numeric\ ID\n\ and\ returning\ a\ unique\ user\ id\n\ @uuid\ -\ a\ unique\ string\ starting\ with\ @prefix,\ and\ concat.\ with\ a\ random\ number\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
+comment3.text=\n\ Inserts\ object\ value\ reservation\ alongside\ key\ of\ @reservationNo\ into\ @libraryReservationMap.\n
-comment4.params=
+comment4.params=prefix\ length
-comment4.target=void\ writeUserData()
+comment4.target=java.lang.String\ generateUserID(java.lang.String,\ int)
-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
+comment4.text=\n\ Returns\ a\ random\ unique\ user\ ID\ by\ specifying\ \n\ @prefix\ -\ arbitrary\ alphanumeric\ prefix\n\ @length\ -\ length\ of\ numeric\ ID\n\ and\ returning\ a\ unique\ user\ id\n\ @uuid\ -\ a\ unique\ string\ starting\ with\ @prefix,\ and\ concat.\ with\ a\ random\ number\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
 comment5.params=
-comment5.target=void\ printAll()
+comment5.target=void\ writeUserData()
-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
+comment5.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
 comment6.params=
-comment6.target=void\ readData()
+comment6.target=void\ printAll()
-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
+comment6.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
-numComments=7
+comment7.params=
+comment7.target=void\ readData()
+comment7.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=8

Semester 2/Programming 2/Project/Part 2/Library.java

@@ -7,10 +7,13 @@
  */
 
 // Import all required libraries. Not using .* as it is not good practice due to potential conflicts.
+import java.util.List;
 import java.util.ArrayList;
 import java.util.HashSet;
 import java.util.Scanner;
 import java.util.Random;
+import java.util.Map;
+import java.util.HashMap;
 import java.io.File;
 import java.io.IOException;
 import java.awt.FileDialog;
@@ -19,40 +22,65 @@ import java.io.PrintWriter;
 
 public class Library
 {
-    private ArrayList<LibraryItem> itemList; // Initialise an ArrayList of name itemList to store Library Items
+    // private List<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 List<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
     
+    private Map<String, LibraryUser> customerMap;
+    private Map<String, LibraryItem> itemsMap;
+    private Map<String, LibraryReservation> libraryReservationMap;
     /*
      * Constructor for objects of class Library
      */
     public Library()
     {
-        itemList = new ArrayList<LibraryItem>();
+        // itemList = new ArrayList<LibraryItem>();
-        userList = new ArrayList<LibraryUser>();
+        // userList = new ArrayList<LibraryUser>();
         uuidSet = new HashSet<String>();
+        
+        customerMap = new HashMap<String, LibraryUser>();
+        itemsMap = new HashMap<String, LibraryItem>();
+        libraryReservationMap = new HashMap<String, LibraryReservation>();
     }
     
     /*
-     * Appends a LibraryItem to the itemList.
+     * Inserts object value item alongside key of @itemCode into @itemsMap.
      */
     public void storeItem( LibraryItem item )
     {
-        itemList.add( item );
+        // itemList.add( item );
+        itemsMap.put( item.getItemCode(), item );
     }
     
     /*
-     * Appends a LibraryUser to the userList.
+     * Inserts object value user alongside key of @userID into @customerMap.
+     * If the userID is set to unknown, it will call @generateUserID.
      */
     public void storeUser( LibraryUser user )
     {
-        userList.add( user );
+        // userList.add( user );
+        System.out.println( "User Storing: " + user.getFirstName() );
         if ( user.getUserID().equals( "unknown" ) )
         {
             user.setUserID( generateUserID( "AB-", 6 ) );
         }
+        customerMap.put( user.getUserID(), user );
     }
     
+    /*
+     * Inserts object value reservation alongside key of @reservationNo into @libraryReservationMap.
+     */
+    public void storeLibraryReservation( LibraryReservation reservation )
+    {
+        libraryReservationMap.put( reservation.getReservationNo(), reservation );
+    }
+    
+    public void generateReservationNo()
+    {
+        if( libraryReservationMap.values() = null )
+            return "000001";
+        
+    }
     /*
      * Returns a random unique user ID by specifying 
      * @prefix - arbitrary alphanumeric prefix
@@ -111,7 +139,8 @@ public class Library
             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 ){
+            // for ( LibraryUser user : userList ){
+            for ( LibraryUser user : customerMap.values() ) {
                 user.writeData( writer );
             }
             writer.close();
@@ -129,7 +158,7 @@ public class Library
     public void printAll()
     {
         System.out.println("\n\nStart Detail Print");
-        for( LibraryItem item : itemList )
+        for( LibraryItem item : itemsMap.values() )
         {
             System.out.println("---------------");
             item.printDetails();
@@ -215,6 +244,7 @@ public class Library
                     }
                     else if ( typeFlag.equals( "user" ) ) {
                         //Process User Data
+                        System.out.println( "User: " + lineItem );
                         Scanner detailScanner = new Scanner ( lineItem ).useDelimiter(",");
                         LibraryUser user = new LibraryUser();
                         user.readData( detailScanner );

Semester 2/Programming 2/Project/Part 2/LibraryReservation.ctxt

@@ -0,0 +1,35 @@
+#BlueJ class context
+comment0.params=reservationNo\ itemCode\ userID\ startDate\ noOfDays
+comment0.target=LibraryReservation(java.lang.String,\ java.lang.String,\ java.lang.String,\ java.lang.String,\ int)
+comment0.text=\n\ Constructor\ for\ objects\ of\ class\ LibraryReservation\n
+comment1.params=
+comment1.target=java.lang.String\ getReservationNo()
+comment1.text=\n\ Return\ value\ of\ @reservationNo\n
+comment10.params=noOfDays
+comment10.target=void\ setNoOfDays(int)
+comment10.text=\n\ Set\ @noOfDays\ to\ a\ new\ value\n
+comment2.params=
+comment2.target=java.lang.String\ getItemCode()
+comment2.text=\n\ Return\ value\ of\ @itemCode\n
+comment3.params=
+comment3.target=java.lang.String\ getUserID()
+comment3.text=\n\ Return\ value\ of\ @userID\n
+comment4.params=
+comment4.target=java.util.Date\ getStartDate()
+comment4.text=\n\ Return\ value\ of\ @startDate\n
+comment5.params=
+comment5.target=int\ getNoOfDays()
+comment5.text=\n\ Return\ value\ of\ @noOfDays\n
+comment6.params=reservationNo
+comment6.target=void\ setReservationNo(java.lang.String)
+comment6.text=\n\ Set\ @reservationNo\ to\ a\ new\ value\n
+comment7.params=itemCode
+comment7.target=void\ setItemCode(java.lang.String)
+comment7.text=\n\ Set\ @itemCode\ to\ a\ new\ value\n
+comment8.params=userID
+comment8.target=void\ setUserID(java.lang.String)
+comment8.text=\n\ Set\ @userID\ to\ a\ new\ value\n
+comment9.params=startDate
+comment9.target=void\ setStartDate(java.lang.String)
+comment9.text=\n\ Set\ @startDate\ to\ a\ new\ value\n
+numComments=11

Semester 2/Programming 2/Project/Part 2/LibraryReservation.java

@@ -0,0 +1,125 @@
+
+/**
+ * A class to track and allow for reservations in a Library
+ * 
+ * @George Wilkinson
+ * @1.0
+ */
+
+import java.util.Date;
+
+public class LibraryReservation
+{
+    // instance variables
+    private String reservationNo;
+    private String itemCode;
+    private String userID;
+    private Date startDate;
+    private int noOfDays;
+    
+    /**
+     * Constructor for objects of class LibraryReservation
+     */
+    public LibraryReservation( String reservationNo, String itemCode, String userID, String startDate, int noOfDays )
+    {
+        this.reservationNo = reservationNo;
+        this.itemCode = itemCode;
+        this.userID = userID;
+        this.startDate = DateUtil.convertStringToDate( startDate );
+        this.noOfDays = noOfDays;
+    }
+
+    /*
+     * Start Accessor
+     */
+    
+    /*
+     * Return value of @reservationNo
+     */
+    public String getReservationNo()
+    {
+        return reservationNo;
+    }
+    
+    /*
+     * Return value of @itemCode
+     */
+    public String getItemCode()
+    {
+        return itemCode;
+    }
+    
+    /*
+     * Return value of @userID
+     */
+    public String getUserID()
+    {
+        return userID;
+    }
+    
+    /*
+     * Return value of @startDate
+     */
+    public Date getStartDate()
+    {
+        return startDate;
+    }
+    
+    /*
+     * Return value of @noOfDays
+     */
+    public int getNoOfDays()
+    {
+        return noOfDays;
+    }
+    
+    /*
+     * End Accessor
+     * 
+     * Start Mutator
+     */
+    
+    /*
+     * Set @reservationNo to a new value
+     */
+    public void setReservationNo( String reservationNo )
+    {
+        this.reservationNo = reservationNo;
+    }
+    
+    /*
+     * Set @itemCode to a new value
+     */
+    public void setItemCode( String itemCode )
+    {
+        this.itemCode = itemCode;
+    }
+    
+    /*
+     * Set @userID to a new value
+     */
+    public void setUserID( String userID )
+    {
+        this.userID = userID;
+    }
+    
+    /*
+     * Set @startDate to a new value
+     */
+    public void setStartDate( String startDate )
+    {
+        this.startDate = DateUtil.convertStringToDate( startDate );
+    }
+    
+    /*
+     * Set @noOfDays to a new value
+     */
+    public void setNoOfDays( int noOfDays )
+    {
+        this.noOfDays = noOfDays;
+    }
+    
+    /*
+     * End Mutator
+     */
+}

Semester 2/Programming 2/Project/Part 2/data/testuserwrite.txt

@@ -1,4 +1,4 @@
-unknown, Newton, David, E, Dr
+AB-906182, Smith, Sara, C, Ms
-unknown, Gregson, Brian, R T, Mr
+AB-241496, Evans, David, , Dr
-unknown, Evans, David, , Dr
+AB-769390, Newton, David, E, Dr
-unknown, Smith, Sara, C, Ms
+AB-396038, Gregson, Brian, R T, Mr

Semester 2/Programming 2/Project/Part 2/nullnull

@@ -0,0 +1,4 @@
+AB-906182, Smith, Sara, C, Ms
+AB-241496, Evans, David, , Dr
+AB-769390, Newton, David, E, Dr
+AB-396038, Gregson, Brian, R T, Mr

Semester 2/Programming 2/Project/Part 2/package.bluej

@@ -17,14 +17,20 @@ dependency5.type=UsesDependency
 dependency6.from=Library
 dependency6.to=LibraryUser
 dependency6.type=UsesDependency
+dependency7.from=LibraryReservation
+dependency7.to=DateUtil
+dependency7.type=UsesDependency
+dependency8.from=Library
+dependency8.to=LibraryReservation
+dependency8.type=UsesDependency
 objectbench.height=76
 objectbench.width=940
 package.editor.height=874
 package.editor.width=814
 package.editor.x=0
 package.editor.y=31
-package.numDependencies=6
+package.numDependencies=8
-package.numTargets=9
+package.numTargets=11
 package.showExtends=true
 package.showUses=true
 project.charset=UTF-8
@@ -39,8 +45,34 @@ target1.showInterface=false
 target1.type=AbstractTarget
 target1.typeParameters=
 target1.width=110
-target1.x=350
+target1.x=130
-target1.y=220
+target1.y=240
+target10.editor.height=700
+target10.editor.width=900
+target10.editor.x=960
+target10.editor.y=146
+target10.height=50
+target10.name=AudioVisual
+target10.naviview.expanded=true
+target10.showInterface=false
+target10.type=AbstractTarget
+target10.typeParameters=
+target10.width=110
+target10.x=380
+target10.y=240
+target11.editor.height=700
+target11.editor.width=900
+target11.editor.x=40
+target11.editor.y=51
+target11.height=50
+target11.name=LibraryReservation
+target11.naviview.expanded=true
+target11.showInterface=false
+target11.type=ClassTarget
+target11.typeParameters=
+target11.width=160
+target11.x=230
+target11.y=440
 target2.editor.height=786
 target2.editor.width=960
 target2.editor.x=34
@@ -52,8 +84,8 @@ target2.showInterface=false
 target2.type=ClassTarget
 target2.typeParameters=
 target2.width=80
-target2.x=580
+target2.x=360
-target2.y=320
+target2.y=340
 target3.editor.height=700
 target3.editor.width=900
 target3.editor.x=557
@@ -65,8 +97,8 @@ target3.showInterface=false
 target3.type=AbstractTarget
 target3.typeParameters=
 target3.width=120
-target3.x=470
+target3.x=250
-target3.y=90
+target3.y=110
 target4.editor.height=1049
 target4.editor.width=1920
 target4.editor.x=0
@@ -78,34 +110,34 @@ target4.showInterface=false
 target4.type=ClassTarget
 target4.typeParameters=
 target4.width=80
-target4.x=690
+target4.x=470
-target4.y=360
+target4.y=380
 target5.editor.height=700
-target5.editor.width=1619
+target5.editor.width=900
-target5.editor.x=192
+target5.editor.x=55
-target5.editor.y=267
+target5.editor.y=274
 target5.height=50
-target5.name=Periodical
+target5.name=LibraryUser
 target5.naviview.expanded=true
 target5.showInterface=false
 target5.type=ClassTarget
 target5.typeParameters=
-target5.width=90
+target5.width=110
-target5.x=280
+target5.x=100
-target5.y=360
+target5.y=170
 target6.editor.height=700
-target6.editor.width=900
+target6.editor.width=1619
-target6.editor.x=55
+target6.editor.x=192
-target6.editor.y=274
+target6.editor.y=267
 target6.height=50
-target6.name=LibraryUser
+target6.name=Periodical
 target6.naviview.expanded=true
 target6.showInterface=false
 target6.type=ClassTarget
 target6.typeParameters=
-target6.width=110
+target6.width=90
-target6.x=320
+target6.x=60
-target6.y=150
+target6.y=380
 target7.editor.height=1049
 target7.editor.width=1920
 target7.editor.x=0
@@ -117,31 +149,31 @@ target7.showInterface=false
 target7.type=ClassTarget
 target7.typeParameters=
 target7.width=80
-target7.x=400
+target7.x=180
-target7.y=320
+target7.y=340
-target8.editor.height=1049
+target8.editor.height=700
-target8.editor.width=1920
+target8.editor.width=900
-target8.editor.x=0
+target8.editor.x=40
-target8.editor.y=31
+target8.editor.y=51
 target8.height=50
-target8.name=Library
+target8.name=DateUtil
 target8.naviview.expanded=true
 target8.showInterface=false
 target8.type=ClassTarget
 target8.typeParameters=
-target8.width=100
+target8.width=80
-target8.x=480
+target8.x=70
-target8.y=220
+target8.y=10
-target9.editor.height=700
+target9.editor.height=1049
-target9.editor.width=900
+target9.editor.width=960
-target9.editor.x=960
+target9.editor.x=0
-target9.editor.y=146
+target9.editor.y=31
 target9.height=50
-target9.name=AudioVisual
+target9.name=Library
 target9.naviview.expanded=true
 target9.showInterface=false
-target9.type=AbstractTarget
+target9.type=ClassTarget
 target9.typeParameters=
-target9.width=110
+target9.width=100
-target9.x=600
+target9.x=260
-target9.y=220
+target9.y=240