You startAsync fine, but then don't test to see if it was started before.
That handler is reentrant for a single request processing.
The behavior depends on how the suspend / resume works out.
You might want to ensure that you don't attempt to start the AsyncContext
twice.
There are many different ways to accomplish this.
One possible approach.
AsyncContext context = (AsyncContext)
request.getAttribute(AsyncContext.class.getName());
if(context == null) {
context = request.startAsync();
request.setAttribute(AsyncContext.class.getName(), context);
ServletInputStream inputStream = request.getInputStream();
inputStream.setReadListener(new ReadListener() { ... });
} else {
System.out.println("Re-entrant AsyncContext");
// do what you want/need here.
// this could even be an error handling routine.
}
Also of note, since you are using a naked Handler, it will always be called.
Even if you have something after that handler, or a RequestDispatcher call,
or an error handling, etc ...
Joakim Erdfelt / [email protected]
On Mon, Dec 21, 2015 at 5:39 AM, Robben, Bert <[email protected]>
wrote:
> When I put my Jetty server under high load, I sometimes get
> IllegalStateException being thrown mentioning “ReadListener already set”.
> These exceptions are thrown when a ReadListener is set more than once to
> the inputstream of an incoming request. However, I never do that. I can
> only explain this if the same request is sent to my handler multiple times,
> which I don’t really understand. Can somebody explain how this can happen
> so that I can avoid these exceptions? Note that I don’t get these exception
> under light load.
>
>
>
> Here’s some more background:
>
>
>
> (1) I’m using jetty 9.3.6.v20151106
>
> (2) I’m running an embedded Jetty
>
> (3) I only have a single request handler. It extends
> AbstractHandler and does the following:
>
>
>
> public void handle(String target, Request baseRequest,
> HttpServletRequest request, HttpServletResponse response) throws
> IOException, ServletException {
>
> String id = request.getRequestURI().substring(1);
>
> baseRequest.setHandled(true);
>
> long count = requests.decrementAndGet();
>
> if (count < 0) {
>
> requests.incrementAndGet();
>
> response.setStatus(HttpStatus.SERVICE_UNAVAILABLE_503);
>
> return;
>
> }
>
> AsyncContext context = request.startAsync();
>
> ServletInputStream inputStream = request.getInputStream();
>
> inputStream.setReadListener(new ReadListener() { ... });
>
> }
>
>
>
>
>
> So as you can see, all requests are handled asynchronously unless my
> server is overloaded (which is not the case when the exceptions occur).
>
>
>
>
>
> Thanks,
>
>
>
> Bert
>
>
>
> PS: Here’s the complete stacktrace
>
>
>
> java.lang.IllegalStateException: ReadListener already set
>
> at
> org.eclipse.jetty.server.HttpInput.setReadListener(HttpInput.java:528)
> ~[opf-0.0.1-SNAPSHOT-allinone.jar:na]
>
> at
> com.clear2pay.opf.realtime.rest.HttpRequestHandler.handle(HttpRequestHandler.java:56)
> ~[opf-0.0.1-SNAPSHOT-allinone.jar:na]
>
> at
> org.eclipse.jetty.server.handler.HandlerWrapper.handle(HandlerWrapper.java:119)
> ~[opf-0.0.1-SNAPSHOT-allinone.jar:na]
>
> at org.eclipse.jetty.server.Server.handleAsync(Server.java:567)
> ~[opf-0.0.1-SNAPSHOT-allinone.jar:na]
>
> at
> org.eclipse.jetty.server.HttpChannel.handle(HttpChannel.java:393)
> [opf-0.0.1-SNAPSHOT-allinone.jar:na]
>
> at org.eclipse.jetty.server.HttpChannel.run(HttpChannel.java:262)
> [opf-0.0.1-SNAPSHOT-allinone.jar:na]
>
> at
> org.eclipse.jetty.util.thread.QueuedThreadPool.runJob(QueuedThreadPool.java:654)
> [opf-0.0.1-SNAPSHOT-allinone.jar:na]
>
> at
> org.eclipse.jetty.util.thread.QueuedThreadPool$3.run(QueuedThreadPool.java:572)
> [opf-0.0.1-SNAPSHOT-allinone.jar:na]
>
> at java.lang.Thread.run(Thread.java:745) [na:1.8.0_66]
>
> 12:27:09.743 [qtp2027944996-257] WARN
> org.eclipse.jetty.server.HttpChannel - ERROR_DISPATCH loop detected on
> Request[POST //be-nft4-app-04:8080/590715314303067]@5928fccb
> java.lang.IllegalStateException: ReadListener already set
>
> 12:27:09.743 [qtp2027944996-309] WARN
> org.eclipse.jetty.server.HttpChannel - ERROR_DISPATCH loop detected on
> Request[POST //be-nft4-app-04:8080/590715314304262]@7d407fdb
> java.lang.IllegalStateException: ReadListener already set
>
>
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