Due: 10:00 AM, Monday, 9/22/08

(a) A container class is a class that contains objects. Java has lots of container classes, but this assignment is to implement some simple container classes of your own design.

• maxSize is an integer constant that will be used by the derived classes of Bag to specify the maximum number of elements that can be stored in any instance of the class. For this assignment, you should set it to some small value, like 5.
• isEmpty() is an abstract method. It will be implemented by the derived classes to indicate whether or not an instance contains any elements.

Class Multiset is an extension of Bag. It must implement the method in Bag, and all the methods that it declares. A multiset is like a set in that the order of its elements does not matter, but it is different from a set in that it may have multiple copies of its elements.

• Multiset() is a constructor that initializes the instance of the new object as an empty multiset.
• Multiset(Object element) is a constructor that initializes the instance of the new object as as a multiset containing the single element passed to it.
• add(Object element) is a method that adds the element to the multiset, returning true if successful and false otherwise.
• delete(Object element) is a method that deletes the element from the multiset, returning true if successful and false otherwise.
• equals(Multiset m) is a method that compares this multiset with the multiset m, returning true if and only if they are equal. Equal does not mean they have the same reference; it means every element in either one of the multisets occurs the same number of times in the other one.

Class Set is an extension of Multiset. It overrides the add method and inherits all the other methods from Multiset.

• Set() is a constructor that initializes the instance of the new object as an empty set.
• Set(Object element) is a constructor that initializes the instance of the new object as as a set containing the single element passed to it.
• add(Object element) is a method that adds the element to the multiset, returning true if successful and false otherwise. One possibility that causes it to return false is if the element is already in the set.

You should also create a class TestBag which contains the main method. It should create several instances each of Multiset and Set that contain Objects of type Character or Integer (not char or int) and demonstrate that the class methods work correctly. Each instance need only contain objects of one type. TestBag does not need to check for user errors, but depending on how you implement the assignment, your methods may need to have some checks to prevent abnormal program termination. You don't need to use try and catch blocks yet.

(b) Add comment documentation to your program (all the classes including TestBag) and use javadoc to extract the documentation into an HTML file. Include a javadoc comment for each class and each method. The class comment should include your name and the date (use the @author tag). Method comments should briefly describe the purpose of the method, its arguments, and what, if anything, it returns (using @param and @return as appropriate). Although these are small classes now, and this may seem like a lot of commenting, we will expand on this assignment at a later date.

The physical location of the javadoc comments is critical. A class comment must immediately precede the line containing the keyword class, and method comments must immediately precede the method.

When you have commented your source files, run javadoc to create the .html files and view them in a browser of your choice.

• Turn in a hardcopy printout of your java source files Bag.java, Multiset.java, Set.java, and TestBag.java, and a printout of your test runs. Do not give me a copy of the javadoc.html files.
• All Java programs will be submitted by copying (or ftping) them to a specially designated directory in AFS. Each person in the class has a subdirectory which has the same name as your login in /afs/cu/class/cs242/fa08

  Within this individual directory, create a subdirectory named p4. Copy only the source files into this directory, not class files or javadoc files. So, for example, if your login name was smithjd then the four .java files should be copied to /afs/cu/class/cs242/fa08/smithjd/p4. These directories have permissions set so that no one other than yourself and Prof. Lynch can read the files. You may, of course, use whatever operating system and compiler you wish to develop your code, but the version you turn in, both hardcopy and the files submitted to AFS, must compile and run under JDK installed in the Clarkson ITL (our lab room).

• Correct execution. The program must follow all the specifications above. The hardcopy of your program's execution should clearly demonstrate that it does. You may want to turn in hardcopy of more than one execution.
• Correct implementation. The program must follow all the design requirements above, in particular the the structure of the three container classes.
• Readability of the code: commented and well-structured, so that it is clear what the code is doing. Use an accepted programming style. The style of the text is fine, or you can follow the Code Conventions. Whatever you do, be consistent.
• Thoroughness of testing. TestBag should clearly demonstrate that all the methods in Multiset and Set work correctly. I may use my own version of TestBag too.
• Timely submission of your program. All hardcopy must be turned in by the deadline. Late programs will not be accepted. Printouts submitted electronically will be ignored.
• Plagiarism (copying all or part of anyone else's code) is a serious infraction of Clarkson regulations; the penalty is a grade of 0 for the first infraction, a final grade of F for further infractions.