On JBoss AS 7.02 I tried the Servlet 3 asynchronous support. As a test I created an infinite dispatch loop:
The Servlet:
@WebServlet(urlPatterns = "/asynctest", asyncSupported = true)
public class AsyncServlet extends HttpServlet {
private static final long serialVersionUID = 1L;
@EJB
private AsyncBean asyncBean;
public void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
AsyncContext asyncContext = request.startAsync();
asyncBean.doAsyncStuff(asyncContext);
System.out.println("After handing work to asyncbean");
}
}
The worker:
@Stateless
public class AsyncBean {
@Asynchronous
public void doAsyncStuff(AsyncContext asyncContext) {
try {
Thread.sleep(SECONDS.toMillis(1));
} catch (InterruptedException e) {
e.printStackTrace();
}
System.out.println("Async work done, dispatching to Servlet container");
asyncContext.dispatch();
}
}
The classes were put in a .war (without any other files) and deployed to JBoss AS 7.02.
The result is that the first call to request.startAsync(); indeed starts asynchronous processing (the client keeps waiting for the response), but after the worker dispatches the work back to the Servlet, the second call to request.startAsync(); seems to be ignored and after the doGet method ends the response is closed.
I'm not 100% sure, but it seems this is not entirely correct. The JavaDoc for AsyncContext#dispatch() says the following:
Control over the request and response is delegated to the dispatch target, and the response will be closed when the dispatch target has completed execution, unless ServletRequest#startAsync() or ServletRequest#startAsync(ServletRequest, ServletResponse) are called.
(emphasis by me)
I tested it on GlassFish and there a loop does occur with a continous dispatching between the worker and servlet happening.
