CMSC491D Design Patterns In Java : Project 2

UMBC | CSEE | Tarr | CS491D

CMSC491D Design Patterns In Java

Fall 1999

Project 2

RMI Chat Server Project

Due Date: December 8, 1999

Project Description

In this project, you will be implementing a simple chat server using RMI. Once clients establish a chat session with the server, they can send messages to the server which then broadcasts the messages to all other clients participating in the chat session.

This application will require that both the client and server have remote objects. The server has a remote object which implements the following interface:

      public interface ChatServer extends Remote {
         public void registerClient(ChatClient client) 
            throws RemoteException;
         public void unregisterClient(ChatClient client) 
            throws RemoteException;
         public void broadcast(String msg) throws RemoteException;
         public String[] getHistory(int n) throws RemoteException;
      }

These methods do the following:

public void registerClient(ChatClient client) - registers the client with the chat server. Note that the object registered is a remote reference to a ChatClient object on the client host.
public void unregisterClient(ChatClient client) - unregisters the client with the chat server.
public void broadcast(String msg) - add the String msg to the history of the chat session and notifies all registered clients of the new message. Notification is done by invoking the update() method of the remote ChatClient objects.
public String[] getHistory(int n) - returns the n most recent mesages added to the chat session.

The client has a remote object which implements the following interface:

      public interface ChatClient extends Remote {
         public void update(String msg) throws RemoteException;
      }

This is the object that the client registers with the chat server. The update() method of this interface does the following:

public void update(String msg) - invoked by the chat server for each registered ChatClient. The String msg is the current message being broadcast to all registered clients.

Project Requirements

Use the above interfaces to write a working version of the RMI chat server application. Implement both the server and the client programs.

Implement the client interface any way you like, either textual or graphical.

Test your application with at least two clients and the server.

Your project code must also be well documented and use a reasonable indentation style. In particular, places where design patterns are implemented should be noted in the code.

Finally, a short report, no more than five pages in length, should be submitted describing the design patterns that appear in your project, either as part of the RMI framework itself or explicitly as part of your server or client implementation.

Project Grading

Your project will be graded according to the following criteria:

Program Correctness - 85%
- The program performs all of its required functions properly.
- The program has no bugs.
- The program handles appropriate error conditions properly.
- The program operates with reasonable efficiency.
Coding Style - 10%
- Good, professional documentation.
- Good readability and understandability.
- Proper use of indentation to highlight function flow control.
- Proper use of blank lines to highlight distinct sections of a function.
Project Report - 5%

As in all your work, NO COPYING OR PLAGIARISM. If such is detected, no credit for the project will be given and appropriate actions for academic dishonesty will be taken.

Project Submission

You must submit the following:

All source files.
All class files.
Any makefile, if used.
Your report file.

Submit all of the above using the submit program. To submit, you type

        submit cs491d project2 <filenamelist>

where filenamelist is a list of one or more files. You can submit a file as often as you like; the latest file submitted overwrites any previous submissions. To list the names of the files you have submitted, type

        submitls cs491d project2

To remove a previously submitted file, type

        submitrm cs491d project2 <filename>

Project Due Date

This project is due December 8, 1999. You have a five day, automatic, no-need-for-a-lame-excuse grace period.

No project will be accepted after December 13, 1999. NO EXCEPTIONS! NO EXCUSES!

Bob Tarr
University of Maryland, Baltimore County
tarr@umbc.edu

UMBC | CSEE | Tarr | CS491D