By the way, in case this gives you more information, my "DataPanel" is very similar to the "OpenFlashChart" Panel class defined in http://cwiki.apache.org/WICKET/open-flash-chart-and-wicket.html, as in fact my flash object is Open Flash Chart (I am loading many charts in the same page in an asynchronous way).
Regards, Daniel. 2009/4/23 Daniel Fernandez <[email protected]>: > Thank you again for your time, Igor. > > Your explanation makes sense by itself, but it is not my problem, I'm > afraid... this thing can happen to me even the first time I load the > page, without reloading at all. > > I investigated deeper and I realised that what was happening was that, > when the server received the request from the flash object for > retrieving the data (a request on the IResourceListener interface of > the DataPanel)... the onBeforeRender() method of the outer container > was being executed some times (and this onBeforeRender created a new > LoadingPanel, which is what caused the exception)... and this makes > no sense to me. > > Let me put it clear, once loaded by the DataPanel onto the browser, > the flash object requests: > > http://myserver/MyPage/wicket:interface/:5:outerpanel:panelloader:datapanel::IResourceListener:: > > Which means that it is calling the datapanel which created the flash > object itself as a resource listener, to simply obtain a resource > declared there (a WebResource object) containing a String of data in > JSON format. > > In my understanding this request, which is executed via the > XmlHttpRequest object in the browser, should never provoke > "outerpanel"'s onBeforeRender() method to execute... but it does! I > put a log sentence in this onBeforeRender method which outputs > "RequestCycle.get().getRequest().getURL()" and I receive an URL like > the one above... but only sometimes, only when it fails. > > Is this possible, is there something I am not understanding about the > way this URL should be served? > > Thanks again, > Daniel. > > > > > 2009/4/22 Igor Vaynberg <[email protected]>: >> browsers are asynchronous, so you might have a race codition. eg >> browser requests the data url and you press the refresh button, so now >> there are two urls in the queue: the data and the page. if page is >> processed first then the data url will fail because when the page is >> first constructed you have a loading panel in there. makes sense? >> >> take a look at wicket's ajaxlazyloadingpanel, it might have a way to >> handle this. >> >> -igor >> >> On Wed, Apr 22, 2009 at 10:23 AM, Daniel Fernandez >> <[email protected]> wrote: >>> Thanks for your answer, Igor. >>> >>> Now I know what is happening more in detail. It is not easy to >>> explain, sorry for the long text: >>> >>> I have: >>> >>> - DataPanel: a panel with data I want to show. >>> >>> - LoadingPanel: a panel which just shows a "loading..." image. >>> >>> - PanelLoader: a Panel with an inner panel called "content", which >>> is loaded initially with LoadingPanel, and sets an AjaxTimerBehavior >>> which polls the server until the data is ready, and then creates the >>> DataPanel, replaces the inner "content" with this DataPanel, and stops >>> the timer behavior. >>> >>> >>> All this works perfectly until I use a subclass of DataPanel called >>> FlashDataPanel which, for showing data, shows a flash object which in >>> turn has to make a request from the browser to get its data. I offer >>> this data to the flash object as a resource, by making this subclass >>> of DataPanel implement IResourceListener, and implementing its >>> "onResourceRequested" method. The URL I add to the flash object is >>> obtained like: >>> >>> CharSequence dataPath = >>> RequestCycle.get().urlFor(FlashDataContainer.this, >>> IResourceListener.INTERFACE); >>> return RequestUtils.toAbsolutePath( dataPath.toString() ); >>> >>> The problems seems to be that *sometimes, and only sometimes* (maybe >>> once each 50 correct loads or so), the "onResourceRequested" method >>> gets called on the LoadingPanel instead of the DataPanel... which is >>> something strange to my eyes (unless there is something I don't >>> understand, of course). The URL is created passing the >>> FlashDataContainer.this object, so I cannot understand how it gets >>> called on a LoadingPanel, which of course does not implement >>> IResourceListener, and thus provokes this exception. >>> >>> Regards, >>> Daniel. >>> >>> >>> >>> 2009/4/22 Igor Vaynberg <[email protected]>: >>>> why dont you set a breakpoint for classcastexception and see what it >>>> is trying to cast to what. >>>> >>>> -igor >>>> >>>> On Wed, Apr 22, 2009 at 3:52 AM, Daniel Fernandez <[email protected]> >>>> wrote: >>>>> Hello, >>>>> >>>>> I have a page which makes quite a heavy use of an >>>>> AbstractAjaxTimerBehavior for retrieving the content of some Panels >>>>> (and stops itself after the content is ready, like a sort of >>>>> "polling") and I am getting a very strange exception which only seems >>>>> to appear randomly: >>>>> >>>>> >>>>> ------------- >>>>> >>>>> 2009-04-22 12:21:30,592 ERROR [RequestCycle] (RequestCycle.java:1463) >>>>> - Method onResourceRequested of interface >>>>> org.apache.wicket.IResourceListener targeted at component >>>>> [MarkupContainer [Component id = content]] threw an exception >>>>> org.apache.wicket.WicketRuntimeException: Method onResourceRequested >>>>> of interface org.apache.wicket.IResourceListener targeted at component >>>>> [MarkupContainer [Component id = content]] threw an exception >>>>> at >>>>> org.apache.wicket.RequestListenerInterface.invoke(RequestListenerInterface.java:199) >>>>> at >>>>> org.apache.wicket.request.target.component.BookmarkableListenerInterfaceRequestTarget.processEvents(BookmarkableListenerInterfaceRequestTarget.java:163) >>>>> at >>>>> org.apache.wicket.request.AbstractRequestCycleProcessor.processEvents(AbstractRequestCycleProcessor.java:92) >>>>> at >>>>> org.apache.wicket.RequestCycle.processEventsAndRespond(RequestCycle.java:1192) >>>>> at org.apache.wicket.RequestCycle.step(RequestCycle.java:1271) >>>>> at org.apache.wicket.RequestCycle.steps(RequestCycle.java:1370) >>>>> at org.apache.wicket.RequestCycle.request(RequestCycle.java:501) >>>>> at >>>>> org.apache.wicket.protocol.http.WicketFilter.doGet(WicketFilter.java:455) >>>>> at >>>>> org.apache.wicket.protocol.http.WicketFilter.doFilter(WicketFilter.java:288) >>>>> at >>>>> org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:215) >>>>> at >>>>> org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:188) >>>>> at >>>>> org.springframework.orm.hibernate3.support.OpenSessionInViewFilter.doFilterInternal(OpenSessionInViewFilter.java:198) >>>>> at >>>>> org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:76) >>>>> at >>>>> org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:215) >>>>> at >>>>> org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:188) >>>>> at >>>>> org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:213) >>>>> at >>>>> org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:172) >>>>> at >>>>> org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:127) >>>>> at >>>>> org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:117) >>>>> at >>>>> org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:108) >>>>> at >>>>> org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:174) >>>>> at >>>>> org.apache.coyote.http11.Http11Processor.process(Http11Processor.java:875) >>>>> at >>>>> org.apache.coyote.http11.Http11BaseProtocol$Http11ConnectionHandler.processConnection(Http11BaseProtocol.java:665) >>>>> at >>>>> org.apache.tomcat.util.net.PoolTcpEndpoint.processSocket(PoolTcpEndpoint.java:528) >>>>> at >>>>> org.apache.tomcat.util.net.LeaderFollowerWorkerThread.runIt(LeaderFollowerWorkerThread.java:81) >>>>> at >>>>> org.apache.tomcat.util.threads.ThreadPool$ControlRunnable.run(ThreadPool.java:689) >>>>> at java.lang.Thread.run(Thread.java:619) >>>>> Caused by: java.lang.IllegalArgumentException: >>>>> java.lang.classcastexcept...@42ae5f >>>>> at sun.reflect.GeneratedMethodAccessor38.invoke(Unknown Source) >>>>> at >>>>> sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAc1cessorImpl.java:25) >>>>> at java.lang.reflect.Method.invoke(Method.java:597) >>>>> at >>>>> org.apache.wicket.RequestListenerInterface.invoke(RequestListenerInterface.java:182) >>>>> ... 26 more >>>>> >>>>> >>>>> ------------- >>>>> >>>>> >>>>> The problem is this I don't get more information than that, and I only >>>>> get the exception once each, say... 50 times I reload the page (I mean >>>>> "browser reload" = new page object). The other 49 times everything >>>>> works fine. It's quite random... >>>>> >>>>> Any clues? >>>>> >>>>> >>>>> Regards, >>>>> Daniel. >>>>> >>>>> --------------------------------------------------------------------- >>>>> To unsubscribe, e-mail: [email protected] >>>>> For additional commands, e-mail: [email protected] >>>>> >>>>> >>>> >>>> --------------------------------------------------------------------- >>>> To unsubscribe, e-mail: [email protected] >>>> For additional commands, e-mail: [email protected] >>>> >>>> >>> >>> --------------------------------------------------------------------- >>> To unsubscribe, e-mail: [email protected] >>> For additional commands, e-mail: [email protected] >>> >>> >> >> --------------------------------------------------------------------- >> To unsubscribe, e-mail: [email protected] >> For additional commands, e-mail: [email protected] >> >> > --------------------------------------------------------------------- To unsubscribe, e-mail: [email protected] For additional commands, e-mail: [email protected]
