New York University

Computer Science Department

Courant Institute of Mathematical Sciences

Session 3: CORBA-Based MOO Framework Installation Instructions

Course Title: XML for Java Developers Course Number: g22.3033-002

Instructor: Jean-Claude Franchitti Session: 3

Installation and Test

1. Extract CORBA-MOO.zip using winzip.

2. After extraction, a directory named CORBA-MOO is created, which includes subdirectory ChatClient and ChatServer.

3. Open the file “vb.bat” in corba directory, change the classpath for Visibroker and current directory.

4. Environment

Insprise Visibroker 4.5 installed

5. Test

> vb.bat

> osagent

> vbj ChatServer.Server

Open another DOS prompt

> vbj ChatClient prof

Open another DOS prompt

> vbj ChatClient student

Design and Implementation

1. The chat room is implemented with CORBA, the client side is a Java application instead of Java applet.

2. IDL

ChatServer.idl describes the interfaces to the server.

connect: called by client when the chat user connects to the server.

disconnect: called by client when the chat user disconnects to the

server.

sendMessage: called by server when new user (dis)connect, or by client

when some user send a message to others.

sendLocation: called by client when some user move his/her position in

the graph.

ChatClient.idl describes the interfaces to the client.

updateMessage: called by server when new messages arrives

updateLocation: called by server when location changed for some user

3. Communication

Message is transferred via a string or integer, while complicated message is encoded in string using special separator “@” instead of using object.

4. Client implementation

Each client has a user list to keep track of all the online users. Each user has a record to record his/her info: like name, location, etc.

The graph of chat room is updated at some time interval, timer is used to decide if a message should be showed in graph.

5. Server implementation

Server has a user list to keep track of all the online users.