[WICKET-2894] page rendering is missing synchronization and eventually gets caught by a race condition (or whatever?!)

• Type: Task
• Status: Resolved
• Priority: Major
• Resolution: Fixed
• Fix Version/s: 1.5-M1
• Component/s: wicket
• Environment: wicket-1.5-trunk, os x 10.6.3, java 1.6.0._20 (64 bit server), safari 4 (same for firefox 3)
• Assignee: Igor Vaynberg
• Reporter: Peter Ertl
• Created: 27/May/10 12:14
• Updated: 18/Aug/10 01:09
• Resolved: 18/Aug/10 01:09

Description

wicket seems to lack some thread synchronization during page render:

I do this...

$ cd wicket-1.5-trunk
$ svn up
$ cd wicket-examples
$ mvn jetty:run

type

http://localhost:8080/wicket-examples

into the browser and navigate to any page (preferrably one that takes a long time to render).

Then I keep hitting [reload] very fast (or just hold the reload-shortcut on the keyboard) and after a while get this exception:

ERROR - RequestCycle - Error during processing error message
java.lang.IllegalStateException: Header was already written to response!
at org.apache.wicket.protocol.http.HeaderBufferingWebResponse.checkHeader(HeaderBufferingWebResponse.java:62)
at org.apache.wicket.protocol.http.HeaderBufferingWebResponse.sendRedirect(HeaderBufferingWebResponse.java:110)
at org.apache.wicket.request.handler.render.WebPageRenderer.redirectTo(WebPageRenderer.java:148)
at org.apache.wicket.request.handler.render.WebPageRenderer.respond(WebPageRenderer.java:246)
at org.apache.wicket.request.handler.RenderPageRequestHandler.respond(RenderPageRequestHandler.java:147)
at org.apache.wicket.request.RequestHandlerStack.executeRequestHandler(RequestHandlerStack.java:86)
at org.apache.wicket.request.cycle.RequestCycle.executeExceptionRequestHandler(RequestCycle.java:269)
at org.apache.wicket.request.cycle.RequestCycle.executeExceptionRequestHandler(RequestCycle.java:278)
at org.apache.wicket.request.cycle.RequestCycle.executeExceptionRequestHandler(RequestCycle.java:278)
at org.apache.wicket.request.cycle.RequestCycle.executeExceptionRequestHandler(RequestCycle.java:278)
at org.apache.wicket.request.cycle.RequestCycle.executeExceptionRequestHandler(RequestCycle.java:278)
at org.apache.wicket.request.cycle.RequestCycle.executeExceptionRequestHandler(RequestCycle.java:278)
at org.apache.wicket.request.cycle.RequestCycle.executeExceptionRequestHandler(RequestCycle.java:278)
at org.apache.wicket.request.cycle.RequestCycle.executeExceptionRequestHandler(RequestCycle.java:278)
at org.apache.wicket.request.cycle.RequestCycle.executeExceptionRequestHandler(RequestCycle.java:278)
at org.apache.wicket.request.cycle.RequestCycle.executeExceptionRequestHandler(RequestCycle.java:278)
at org.apache.wicket.request.cycle.RequestCycle.executeExceptionRequestHandler(RequestCycle.java:278)
at org.apache.wicket.request.cycle.RequestCycle.processRequest(RequestCycle.java:225)
at org.apache.wicket.request.cycle.RequestCycle.processRequestAndDetach(RequestCycle.java:251)
at org.apache.wicket.protocol.http.WicketFilter.processRequest(WicketFilter.java:174)
at org.apache.wicket.protocol.http.WicketFilter.doFilter(WicketFilter.java:209)
at org.mortbay.jetty.servlet.ServletHandler$CachedChain.doFilter(ServletHandler.java:1157)
at org.mortbay.jetty.servlet.ServletHandler.handle(ServletHandler.java:388)
at org.mortbay.jetty.security.SecurityHandler.handle(SecurityHandler.java:216)
at org.mortbay.jetty.servlet.SessionHandler.handle(SessionHandler.java:182)
at org.mortbay.jetty.handler.ContextHandler.handle(ContextHandler.java:765)
at org.mortbay.jetty.webapp.WebAppContext.handle(WebAppContext.java:418)
at org.mortbay.jetty.handler.ContextHandlerCollection.handle(ContextHandlerCollection.java:230)
at org.mortbay.jetty.handler.HandlerCollection.handle(HandlerCollection.java:114)
at org.mortbay.jetty.handler.HandlerWrapper.handle(HandlerWrapper.java:152)
at org.mortbay.jetty.Server.handle(Server.java:326)
at org.mortbay.jetty.HttpConnection.handleRequest(HttpConnection.java:536)
at org.mortbay.jetty.HttpConnection$RequestHandler.headerComplete(HttpConnection.java:915)
at org.mortbay.jetty.HttpParser.parseNext(HttpParser.java:539)
at org.mortbay.jetty.HttpParser.parseAvailable(HttpParser.java:212)
at org.mortbay.jetty.HttpConnection.handle(HttpConnection.java:405)
at org.mortbay.io.nio.SelectChannelEndPoint.run(SelectChannelEndPoint.java:409)
at org.mortbay.thread.QueuedThreadPool$PoolThread.run(QueuedThreadPool.java:582)

to me this seems to be a missing or broken synchronization feature.

if you are "lucky" (in order to reproduce the issue) the screen will be empty....