Question

I have 3 clients. I would like to create an application that shows when each client is online and when not based on the JMS – java messaging and tomcat server. Till now I successfully succeed to create a sending and receiving messaging using JMS (queue1).

I don’t know from where to start in order to make my application alive.

Thank you.
Need help.
Appreciate!

Answer 1

First of all, JMS is quite a heavy-weight way to implement this behaviour. You’d be far better off using a MulticastSocket.

However the basic principle is the same whichever route you take:

1. each client sends a heartbeat messages identifying itself at predefined intervals until it is closed or dies.
2. the monitoring application listens for those heartbeat messages, keeps track of the clients that have identified themselves in the heartbeat messages and assumes a client is dead when the heartbeat messages stop for a given client.

With JMS these messages would be sent to a single queue, with a MulticastSocket you send a DatagramPacket to a group.