CIS 636 Spring 2004 Assignment 3 – Object Oriented Programming in Java – Inheritance 100 points

Assigned: 02/12/2004

Due: 02/19/2004 at the start of class

You may work individually or in pairs for this assignment. But all work must be the work of the person/people whose name is on the code! If working in pairs, the individual contributions should be relatively equal. One possibility is to work together tonight, then finish separately (to avoid communication difficulties).

Main Assignment:

We are building more pieces of a simplified EzPass toll collection program. The next pieces to add include EzPassBridge, and EzPassInterchange which are child classes of EzPassLocation created in Assignment 2. An EzPassBridge should be able to keep track of the price for going over the bridge (assume only one category of customer to keep things simple – no trucks). It should provide a variety of constructors, allowing users a variety of ways to create an EzPass Location. These should include providing the client program the ability to specify info related to the Location - - including the name, city, state, etc). It should provide all necessary accessors – inspectors and mutators, so that data can all be declared as private. Mutators should protect against bad data getting into objects (e.g. bad toll price – nothing should be less than $0.50, nor more than $10.00 (Chesapeake Bay Bridge Tunnel)). The class should support versions of equals and toString appropriate to the class.

An EzPassInterchange should be able to keep track of or calculate the price for exiting at the interchange after entering at any interchange within the same state (leaving one state and entering another represent an exit then an entrance). This may mean having an array or other data structure keeping track of starting interchange and price for each possible starting interchange (assume only one category of customer to keep things simple – no trucks). For right now, many of you may find the easiest way to handle this is parallel arrays – an array of starting interchanges and an array of prices that are kept in synch (if you are finding this all really easy so far, you could look up a data structure designed for lookups, such as HashMaps). The class should provide a variety of constructors, allowing users a variety of ways to create an EzPass Location. These should include providing the client program the ability to specify info related to the Location - - including the name, city, state, etc). There may not be any simple accessors to provide, but significant capabilities are needed: a) Lookup a toll, given a starting interchange; and b) include an additional toll listing, given a starting interchange and a price – important for getting started (make sure the price is valid – let’s say that interchange to interchange tolls can be anywhere from $0.10 to $25). Additional desirable capabilities such as deleting a toll listing, changing a toll price, increasing the toll price by a given percentage, etc should probably be left for another day. The class should support versions of equals and toString appropriate to the class (don’t try to show a whole interchange as part of a price list, it will recurse forever; likewise equals might should skip testing to see if the price lists are the same.

You are to build the classes described above, and also write main program(s) (probably part of the same classes) that will test out the capabilities of the classes (thoroughly). You will need to create several interchanges to test out that class; you can hack those up in code instead of asking the user for a bunch of information as part of setup. If you do do any input, I encourage you to keep using my RedmondMsgInBasic. Cancels on input dialog boxes will not be fully handled unless you use “robust versions” (which will require that you also download exception files).

Hand in:

• Disk with an entire folder containing the correct folder structure, your files, any other of my classes that you use, and the corresponding Byte-code files. I should be able to get into the IDE and run your program without any messing with your files and folders. So test what you are handing in, even if you already tested it on a hard drive or wherever.
• Print out of your code. Make sure you change the print options in the IDE so that comments show up (Ask me about this in class)

To avoid needless long waits, I recommend working on this on the c: drive, then upon completion, copying it to the a: drive, testing it there, creating an extra backup for yourself, then deleting it from the c: drive.

Miscellaneous:

· MAKE SURE YOUR PROGRAM WORKS! (i.e. more than just removing compile errors). Make your class as robust as possible in preparation for future use.

· Make sure that your main demonstrates that your class methods work.

· Put YOUR NAME, and e-mail address and date in comments at the beginning of the program.

· Also, comment any significant code to document it (each method, each loop, each if, and each significant calculation should have a comment. In particular, each method needs to have a JAVADOC compatible comment).

· Indent code following standard conventions (indent to show that something is “inside” or “part of” the preceding code (e.g. inside if’s or loops, or statements continued on a new line). The IDE should handle this if you hit ENTER and move on to the next line (If you make changes, you may need to TAB to make things right).

· Name your variables meaningfully, to describe their use in the program.