CODEWITHSUNDEEP
javagwtrpc
MTilsted
MTilsted

Reputation: 5545

detect canceled requests on server when using gwt-rpc

In the gwt client I can cancel a request by letting the method in the Async interface return a Request object which contains a cancel() method I can call.

So far so good, but is there a way to detect this in the java code running on the server?

My use-case is that I have a rpc call which take a long time to complete on the server, and where the user has a "cancel" button to stop the request.

And If the user cancel the request, the server should stop processing, but there seems to be no way to detect that the client have closed the connection.

Upvotes: 1

Views: 438

Answers (1)

yurgis
yurgis

Reputation: 4067

It is usually not a good idea to use server's request threads for long running tasks. You need to redesign them to be executed asynchronously (if you still have not done it). You can utilize java.util.concurent tools like FutureTask and Executors to achieve this. You will also need to use thread pools to make sure to control a max number of concurrent tasks.

When you submit a request for a long task from the client, you need to return a reference key (e.g. UUID or some unique string) to your FutureTask as soon as you schedule it for execution. Then to cancel the task, you need pass the key from the client and look up you task and cancel it:

See javadoc for more details:

http://docs.oracle.com/javase/7/docs/api/java/util/concurrent/FutureTask.html

Upvotes: 1

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