Objective

This homework will give you practice designing object-based solutions to problems. In addition, it will allow you to practice using arrays of references and javadoc documentation.

Overview

For this homework you will implement a very simple database system for a Cable TV company. Your program will allow the company to keep track of clients and the different TV channels (e.g., TNT, HBO, WETA, etc.) they manage. Unlike previous homework assignments, we will not provide any support infrastructure for this project. You will design and implement all the classes needed to complete the database application. You may want to take a look at the Sample Run section before you read the detailed description.

This homework will be graded as follows: 60% (Implementation), 25% (Design), 10% (Style), 4% (Your JUnit Test), 1% (Time log)

Specifications

Program Overview

You will write a program that enables a cable company to keep track of the its clients, the channels available to the company and the channels assigns to clients.  The program will handle the following tasks:

• Adding a channel
• Finding information about a channel
• Removing a channel
• Get information about all channels
• Add a client
• Find information about a client
• Remove a client
• Get information about all clients
• Assign a channel to a client
• Compute a client's bill

What you must implement, in a nutshell

You must design and implement a solution to the database application. The design will include documentation for each of the classes that are part of the application and the methods for each class. You are expected to design your own classes for representing the basic entities that the program manipulates. You will document your design in the design.txt file, which is part of the code distribution. After completing your design, you will implement it. The number of classes you decide to use is up to you, however, you must follow the set of restrictions specified below.

Code Distribution

Before you read these specifications, you should access the files associated with this homework by checking out the project named p6. The code distribution provides you with the following:

• ExampleDriver.java - Illustrates how to access the database application via the CableCompany class.
• design.txt - Text file where you will provide a description of your design.
• PublicTests.java - This class represents the set of JUnit public tests. The expected results for each test can be found in the text files with a "pub" prefix.
• SupportPublicTests.java - Methods that support the JUnit tests.
• A time log file.

Database Representation

The database application will be represented using two lists:

• Client list - A list of clients sorted by name.
• Channel list - An unsorted list of Channels.  (New channels are added to the end of this list.)

How you represent these lists is part of your design. You may follow any approach you deem necessary as long as it adheres to the specifications of the homework. Note that you will not use any sorting algorithm in this project. For example, you will keep your client list sorted by inserting elements in the appropriate position in the list. Also, you may not use the ArrayList class for this project.  If you use the ArrayList class you will receive not credit for this homework.

Required Classes

The class CableCompany is the class that provides access to the database application.  You must defined this class with the methods we have specified below.  Aside from this class, it is up to you to define any classes you deem are necessary to complete the project.  However, you must defined at least four classes (in addition to the CableCompany) as part of your design.

We expected some specific classes as part of your design, therefore think carefully before you implement any code.   As you design your classes make them as general as possible so that they can be recycled by other cable company software engineers.  Keep in mind that having a lot of meaningless class doesn't mean you will get a higher grade.

CableCompany

This class represents the database application. Access to the database application is possible through this class. The methods' prototypes and behaviors are defined next. You must not change the following methods' prototypes or add any other public methods.  However, feel free to add any private methods and instance variables you understand are necessary.

Methods (all are public methods)

1. Default Constructor - Feel free to add a default constructor if you understand it is necessary.
2. addChannel: Adds a channel information to the company's channel list. Remember that this list is not sorted and new channels are added to the end of the list. The method's prototype is:

                               public boolean addChannel(String name, int number, double cost);

   The name parameter represents the channel's name. The number represents the channel number assigned to the channel and cost represents the monthly cost for receiving the channel. This method will return true if the add operation was completed successfully and false otherwise. Keep in mind that a channel is uniquely identified by its name.

3. findChannel: Returns a String with information about a particular channel or null if the channel is not part of the database. The method's prototype is:

   public String findChannel(String name);

   The format of the String to return is:

   ChannelString ® "Channel Name: " name "|Number: "number"|Cost: " cost

   where name, number, and cost correspond to the channel's name, number and cost, respectively.

4. removeChannel: Removes the specified channel from the channel list. Returns true if the removal was successful and false otherwise.  The method's prototype is:

public boolean removeChannel(String name);

5. getAllChannels: Returns a String with all the channels or null if no channels are available. The method's prototype is:

public String getAllChannels();

The format of the String to be returned is a sequence of ChannelString each on a line by itself. We refer to this list as the ChannelStringList.

6. addClient: Adds to the database the client whose name and address are specified in the parameters. The method's prototype is:

public boolean addClient(String name, String address);

The collection of clients is kept sorted by client name. Names will be specified by providing the last name first followed by the first name (with a comma in between).  For example, Rose Johnson will be specified as "Johnson,Rose".   The method will return true if the add operation was successful and false otherwise (e.g., if the client is already part of the database).  You can assume users of the CableCompany class will provide names with the expected format (e.g., no spaces before the first and last character of the name).

7. findClient: Returns a String with information about a client or null if the client is not part of the database. The method's prototype is:

public String findClient(String name);

The format of the String to return is one of the following:

ClientString®

 

"Name: "name", Address: "address

"Channel List:"
ChannelStringList

 

 

OR

ClientString®

 

"Name: "name", Address: "address
"Channel List: None"

8. removeClient: Removes the client with the specified name from the database. The method's prototype is:

public boolean removeClient(String name);

Returns true if the remove operation was successful and false otherwise (e.g., the name is not found).

9. getAllClients: Returns a String with the clients that are part of the database or null if no clients are present. The method's prototype is:

public String getAllClients();

The format of the String to be returned is a sequence of ClientString each on a line by itself.

10. assignChannelToClient: Assigns the particular channel to a client.  The method's prototype is:

public boolean assignChannelToClient(String clientName, String channelName);

The method returns true if the assignment is successful and false otherwise (e.g., the customer doesn't exist or the channel is not valid).

11. computeClientsBill: Returns a string representing the clients' bill or null if the client doesn't exist.  The method's prototype is:

        public String computeClientsBill(String clientName);

Requirements/Assumptions

• Client's names are unique and no middle initial will be used.
• A channel is uniquely identified by its name (e.g., "NBO").
• When the program is started there are no clients or channels in the system.
• You may assume the input to your methods is well-formed, e.g., no null-reference arguments.
• To implement a sorted list you may not use any of the Java API data structure classes (such as ArrayList). The lists must be created using arrays of references to objects of classes you defined.
• Provide complete javadoc documentation for only one of the classes you designed. (That is, you must provide a javadoc comment for the entire class and individual javadoc comments for all the public methods.) Indicate in the design.txt file which class you are providing javadoc documentation for.
• You will lose a significant number of points if your program doesn't define at least four meaningful classes.
• You must use the Eclipse debugger during your debugging process.  During TA office hours you will be asked to use the debugger to show the TA doubts you may have about your code.
• As with all programming assignments:
  • You must use meaningful variable names and good indentation.
  • You must avoid code duplication, by calling appropriate methods (rather than cutting and pasting code) and defining appropriate classes. You may define your own private utility methods to perform often repeated tasks.
• Test your program using the provided JUnit module.
• Test your submission using the submit server.

Design Documentation

Complete the design.txt file you will find in the code description.

As mentioned above, you are to provide javadoc documentation for one of your classes, and will indicate which class in your design.txt file. You should not provide the html files generated by the javadoc utility with your submission. We will generate the files ourselves.

To run Javadoc from Eclipse, select the file, right click, and select "Export → Javadoc". The first time you attempt to do this, Eclipse will ask you to specify the location of your javadoc executable. This file will be located in your Java directory, within its bin directory. For example, on a typical Windows machine, this might be:

C:\Program Files\Java\jdk1.5.0_03\bin\javadoc.exe

On a typical Unix/MacOS machine the file will likely just be called "javadoc", and again will be in the Java sdk directory.

Remember to store the javadoc files outside your workspace. When exporting javadoc it will ask you for the "Destination" to store the javadoc documentation files. Please specify a directory that is outside of your Eclipse Workspace, so it does not affect your submission. If you see some directories with the "doc" prefix in your project workspace then you have not specified an appropriate "Destination".

JUnit Tests

We have provided a JUnit test you can use to verify the correctness of your code.  However, you must provide your own JUnit module that shows the set of tests you used to verify your implementation is correct.  Please name your JUnit test module JUnitMyTests.java.

Sample Run

At the end of this page you will find a class ExampleDriver.java and the output that it produces. Access to the database application is through the CompanyCable class you will implement. The class ExampleDriver.java can be found in the code distribution.

Challenge Problem

Remember that you are not required to implement the following problem. Please visit the course web page for information regarding challenge problems. IMPORTANT: If you decide to complete the challenge problem you must provide its implementation in the file called Challenge.java. Remember to define a main method in the Challenge class that allow us to run your program.

The challenge problem consists of defining a GUI for the database software application. The GUI should allow a user to complete all the tasks associated with the CableCompany class. Feel free to define your interface as you understand is best. Keep in mind that a GUI based on JOptionPane is considered a valid GUI although you may not receive the maximum number of gold stars.

Submission

Submit your project using the submit project option associated with Eclipse. Make sure that the submit server generates the expected results.

ExampleDriver.java

public class ExampleDriver {

	public static void main(String[] args) {
		System.out.println("*****Loading some channels*****");
		CableCompany cableCompany = new CableCompany();
		loadChannels(cableCompany);
		System.out.println(cableCompany.getAllChannels());
		

		
		System.out.println("*****Loading some clients*****");
		loadClients(cableCompany);
		System.out.println(cableCompany.getAllClients());
		

		
		System.out.println("*****Looking up some information*****");
		System.out.println("*****Looking information about a channel*****");
		String channelInfo = cableCompany.findChannel("ABD");
		if (channelInfo != null) {
			System.out.println(channelInfo);
		}
		System.out.println("*****Looking information about a client*****");
		String clientInfo = cableCompany.findClient("Smith,Robert");
		if (clientInfo != null) {
			System.out.println(clientInfo);
		}
		

		
		System.out.println("*****Assigning channels to clients*****");
		cableCompany.assignChannelToClient("Smith,Robert", "ABD");
		cableCompany.assignChannelToClient("Smith,Robert", "NBO");
		cableCompany.assignChannelToClient("Smith,Robert", "CBC");
		cableCompany.assignChannelToClient("Anderson,Paola", "NBO");
		System.out.println("*****After assigning ABD, NBO and CBC to Smith,Robert*****");
		System.out.println(cableCompany.findClient("Smith,Robert"));
		System.out.println("*****After assigning NBO to Anderson,Paola*****");
		System.out.println(cableCompany.findClient("Anderson,Paola"));
		

		
		System.out.println("*****Computing client's bill*****");
		System.out.println("Bill: " + cableCompany.computeClientsBill("Smith,Robert"));
	}
	

	private static void loadChannels(CableCompany cableCompany) {
	    cableCompany.addChannel("NBO", 304, 15.00);
	    cableCompany.addChannel("ABD", 7, 3.99);
	    cableCompany.addChannel("CBC", 9, 4.0);
	}
	

	private static void loadClients(CableCompany database) {
	    database.addClient("Smith,Robert", "4100 Berwyn Road Bethesda MD");
	    database.addClient("Johnson,Mary","8000 Silver Lane Colesville MD" );
	    database.addClient("Anderson,Paola","14 St NW Washington DC");
	}
}

Driver's Output

*****Loading some channels*****
Channel Name: NBO|Number: 304|Cost: 15.0
Channel Name: ABD|Number: 7|Cost: 3.99
Channel Name: CBC|Number: 9|Cost: 4.0
*****Loading some clients*****
Name: Anderson,Paola, Address: 14 St NW Washington DC
Channel List: None
Name: Johnson,Mary, Address: 8000 Silver Lane Colesville MD
Channel List: None
Name: Smith,Robert, Address: 4100 Berwyn Road Bethesda MD
Channel List: None
*****Looking up some information*****
*****Looking information about a channel*****
Channel Name: ABD|Number: 7|Cost: 3.99
*****Looking information about a client*****
Name: Smith,Robert, Address: 4100 Berwyn Road Bethesda MD
Channel List: None
*****Assigning channels to clients*****
*****After assigning ABD, NBO and CBC to Smith,Robert*****
Name: Smith,Robert, Address: 4100 Berwyn Road Bethesda MD
Channel List:
Channel Name: ABD|Number: 7|Cost: 3.99
Channel Name: NBO|Number: 304|Cost: 15.0
Channel Name: CBC|Number: 9|Cost: 4.0
*****After assigning NBO to Anderson,Paola*****
Name: Anderson,Paola, Address: 14 St NW Washington DC
Channel List:
Channel Name: NBO|Number: 304|Cost: 15.0
*****Computing client's bill*****
Bill: $22.99

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