What is the equivalent of the code written by jetty.continuation in Jakarta.server.AsyncContext?

Question

I want to upgrade my project from jetty 9 to 12. Since the jetty.continuation is deprecated, I want to replace the following code snippet using AsyncContext class.

        Continuation cont = ContinuationSupport.getContinuation(request);
         .
         .
         .
        cont.setTimeout(suspendMs);
        cont.suspend();

what is the code equivalent?

which method does implement "suspend" in AsyncContext class?

Answer 1

The best source of advice for moving from Jetty Continuations (deprecated in Jetty 8 btw, removed in Jetty 10), is to look at the Servlet3Continuations.java source in the jetty-9.4.x branch.

Methods like suspend() and resume() are not a 1::1 method call on AsyncContext, but in fact multiple method calls.

Continuation to AsyncContext

• Continuation.setTimeout(long) ::

  AsyncContext.setTimeout(long);
  

• Continuation.suspend() ::

  HttpServletRequest.startAsync();
  HttpServletRequest.setTimeout(...);
  HttpServletRequest.addListener(AsyncListener); // handles onTimeout and onComplete
  

• Continuation.suspend(ServletResponse response) ::

  HttpServletRequest.startAsync(request, response);
  HttpServletRequest.setTimeout(...);
  HttpServletRequest.addListener(AsyncListener); // handles onTimeout and onComplete
  

• Continuation.resume() ::

  AsyncContext.dispatch();
  

• Continuation.complete() ::

  AsyncContext.complete();
  

• Continuation.isSuspended() ::

  HttpServletRequest.isAsyncStarted();
  

• Continuation.isResumed() ::

  // no servlet API for this
  

• Continuation.isExpired() ::

  // no servlet API for this
  

• Continuation.isInitial() ::

  if (HttpServletRequest.getDispatcherType() != DispatcherType.ASYNC) {
    // possibly the initial request
    // note, this could be a REQUEST / INCLUDE / FORWARD / ERROR dispatch
  }
  

• Continuation.isResponseWrapped() ::

  // no servlet API for this
  

• Continuation.getServletResponse() ::

  AsyncContext.getRequest();
  AsyncContext.getResponse();
  

• Continuation.addContinuationListener(ContinuationListener) ::

  AsyncContext.addListener(AsyncListener);
  

• Continuation.setAttribute(String, Object) ::

  HttpServletRequest.setAttribute(String, Object);
  

• Continuation.getAttribute(String) ::

  HttpServletRequest.getAttribute(String);
  

• Continuation.removeAttribute(String) ::

  HttpServletRequest.removeAttribute(String);
  

• Continuation.undispatch() ::

  // no servlet API for this