CS476/576

Assignment #6

Due Midnight,  Wednesday   Dec 4, 2002

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Write the following two programs inJava.

NAME

adapter  - helps a tcp chatclient to communicate with a udp chatclient.
chatclient  -  a swing-based program that helps a person to chat with another person  using either a tcp or a udp socket.

adapter [ <port>]
chatclient

• adapter

This program  helps a tcp client to communicate with a udp client.
The program  creates two server sockets A and B where A  is a tcp and B is a udp.
Assume that sockets A and B are both  binded to the same port number.
If no command line argument is  provided, that  port number is 1234.

It is assumed that the program will have only two clients, one is a tcp chatclient and the other is a udp chatclient (the details of these two clients are described next).

When the tcp chatclient is connected,  socket A is closed since there is no
more tcp clients that are expected to connect to this server.
The program  gets the ip/port  information of the udp chatclient from  the first udp message received from the udp chatclient.

Basically the program create two threads:

• The first thread  continuously reads any message from the tcp socket and forwards it to the udp socket.
• The second thread will do the reverse, i.e., it continuously reads any message from the udp socket and forwards it to the tcp socket.

•  chatclient

The program display a swing-based GUI interface similar to the one shown below:
 

 
 

Basically the interface has the following components:

• args: host, port and mode. The host and port are used to contact the adapter. The mode is to set the socket as either tcp or udp.
• push buttons: Go and Quit. The Go button  establishes a tcp connection to the adapter if the mode  is tcp, or to send an empty message to the adapter if the mode is udp.

Clicking on the  Go button:
• enables (i.e., becomes senstive) the input field button and
• disables (i.e., becomes insensitive) the Go button  as well as the args fields.
Clicking on the  Quit buttons displays a dialogue box to confirm or cancel the action.
• input filed:  to  type any  line of text and the Enter key sends the typed line to the adapter.
• received messages area: Any line received from the adapter is appended at the top.