Send data to front end when back end update

[pradeep gamage]

In my web application backend update from several clients. so when backend updates each update should appear on each client. So how i can update client web browser when backend update? I am using jboss, jsf and spring framework. Please give me idea how i can implement my scenario. Thanks in Advance

[Peter Johnson]

I assume your clients are web pages running in a browser. You could use AJAX/JavaScript to occasionally poll the server for updates. There is probably a JSF component that already does this. There might even be an AJAX/JavaScript component for event handling, which would be even better.

[pradeep gamage]

I have found following solutions up to now, that your frontend is a (generally) stateless HTML page of some sort. Something in a browser. If you want all clients to be pushed changes automatically, you have three options:

Comet:
Comet is essentially making AJAX requests that have no request timeout limit. You make the request, and it sits there and streams data through it as is neccessary. This can be done with hidden iFrames or standard XMLHTTPRequests (which jQuery can wrap for you). You can read more about this method here.

Long Polling:
Essentially, you use the javascript setInterval method to continuously poll your server for changes. Simply set an interval that does a standard AJAX GET request to the server, and upon every success, update your page accordingly.

HTML5 WebSockets:
Using any type of Event-Based backend (Twisted, EventMachine, node.js, etc) makes WebSockets the ideal solution. Simply have all clients register with the backend, and upon a submit from any given client, push the changes to all other clients. You can read more (and see a nice example) of WebSockets on this page.

[pradeep gamage]

I found light sreamer also good technique that we can push server side data to client end. light streamer web site