This feature is work-in-progress, and available in 1.7.0-SNAPSHOT. Requires a Servlet3+ container.
Async Actions allows handler methods to behave in an asynchronous (Servlet3) fashion. This is mostly used for performance reasons, when a Stripes Action has to can connect to external services (e.g. a web service) in a non-blocking fashion.
Async event handlers must have the following signature :
public void doSomething(AsyncResponse asyncResponse);
They return void, and accept a single argument of type AsyncResponse.
When handling such events, Stripes will start the asynchronous cycle, and let you complete by invoking one of the asyncResponse.complete() variants.
public class SimpleAsync implements ActionBean {
public void simpleEvent(AsyncResponse asyncResponse) {
// simple without really anything async...
asyncResponse.complete(new ForwardResolution("/WEB-INF/stuff.jsp"));
}
} |
public class ReallyAsync implements ActionBean {
public void asyncEvent(final AsyncResponse asyncResponse) {
// submit to executor service
ExecutorService executor = ... ;
executorService.submit(new Runnable() {
@Override
public void run() {
// do anything in a separate thread and complete with a forward
asyncResponse.complete(new ForwardResolution("/WEB-INF/stuff.jsp"));
}
});
}
} |
public class ReallyAsyncWithLambdas implements ActionBean {
public void asyncEventWithLambda(final AsyncResponse asyncResponse) {
// submit to executor service
ExecutorService executor = ... ;
executorService.submit(() -> {
// do anything in a separate thread and complete with a forward
asyncResponse.complete(new ForwardResolution("/WEB-INF/stuff.jsp"));
});
}
} |
public class WithNonBlockingClient implements ActionBean {
public void nonBlocking(final AsyncResponse asyncResponse) {
// call non blocking http client
httpClient.get('/foo/bar', httpResponse -> {
// client completed : use http response
httpResponse.xyz();
// and complete...
asyncResponse.complete(new ForwardResolution("/WEB-INF/stuff.jsp"));
});
}
} |