Assignment #3: Inheritance

The assignment consists of three completely separate parts.

Part I: Forming an Inheritance Hierarchy

A set of classes is used to handle the different ticket types for a theater. All tickets have a unique serial number that is assigned when the ticket is constructed and a price. There are three basic types of tickets:
Ticket type Description Sample toString Output
WalkupTicket These tickets are purchased on the day of the event for $50 SN: 314, $50
AdvanceTicket Tickets purchased ten or more days in advance cost $30. Tickets purchased fewer than ten days in advance cost $40. SN: 612, $40
StudentAdvanceTicket These are AdvanceTickets that cost half of what an AdvanceTicket would normally cost. SN: 59, $15 (student)
  1. Design a class hierarchy that encompasses the above three classes, and adds an abstract class called Ticket.
  2. Implement the Ticket abstract class. This class should store a serial number as its private data, and the constructor should initialize the serial number. Also keep a static variable lastSerialNumber that can keep track of the last serial number assigned (so you can avoid duplicates). Provide an appropriate abstract method (HINT: what can ALL tickets do?), and also provide an implementation of toString that prints the serial number and price information.
  3. Implement the WalkupTicket class.
  4. Implement the AdvanceTicket class. Provide a constructor that takes a parameter indicating the number of days in advance that the ticket is being purchased. Recall that the number of days of advanced purchase affects the ticket price.
  5. Implement the StudentAdvanceTicket class. Provide a constructor that takes a parameter indicating the number of days in advance that the ticket is being purchased. The toString method should include a notation that this is a student ticket. This ticket costs have of an Advanceticket. If the pricing scheme for AdvanceTicket changes, the StudentAdvanceTicket price should be computed correctly with no code modification to the StudentAdvanceTicket class.
  6. Provide a test program that populates an array of Ticket with all three kinds of tickets, and then calls a function that computes the total cost of all the tickets in the array.

Part II: I/O and the Decorator Pattern

Do some simple I/O using the Java I/O library. You will read a file that contains an unknown number of words into an array of String. Print out the exact number of words read. The file is contained on the Internet. There are two versions of the assignment. Do both.

Version #1

Version #1 of the program gets the file located at http://www.cs.fiu.edu/~weiss/cop3337/assignments/dict.txt. Here is some starter code (you will need to find the appropriate import directives. 
URL url = new URL( "http://www.cs.fiu.edu/~weiss/cop3337/assignments/dict.txt" );
InputStream is = url.openStream( );
Once you have the InputStream you can use a Scanner to read a line at a time. Then you can use ArrayList to store the strings.

Version #2

The URL http://www.cs.fiu.edu/~weiss/cop3337/assignments/dict.ser.gz stores a String[] in compressed gzip form. Open up the URL, wrap inside a BufferedInputStream, then a GZIPInputStream, and then a ObjectInputStream, and call readObject. You will get the entire String array in a single read.

Part III: Interfaces and Function Objects

Method transform takes two identically sized-arrays of double as parameters: input and output, and a third parameter representing a function to be applied to the input array. For instance, in the following code fragment: 
   double [ ] input = { 1.0, -3.0, 5.0 };
   double [ ] output1 = new double [ 3 ];
   double [ ] output2 = new double [ 3 ];
   double [ ] output3 = new double [ 4 ];

   transform( input, output1, new ComputeSquare( ) );
   transform( input, output2, new ComputeAbsoluteValue( ) );
   transform( input, output3, new ComputeSquare( ) );
The intended result is that output1 contains { 1.0, 9.0, 25.0 }, output2 contains { 1.0, 3.0, 5.0 }, and the third call to transform throws an IllegalArgumentException because the arrays have different sizes. Implement the following components:
  1. An interface that will be used to specify the third parameter to transform.
  2. The transform method (which is a static method). Remember to throw an exception if the input and output arrays are not identically-sized.
  3. The classes ComputeSquare and ComputeAbsoluteValue.