The Javadocs for setMetaData() & MetaDataKey are somewhat unclear (to me). It says the meta data key has to be a singleton. This seems to imply you can only store only one piece of metadata for a given component (e.g., a page)? If so, that's not helpful, since I have to to store many potentially many (similar) pieces of data (read FutureTask) for the same page in a multi-user environment: That is, one for each user who's running the background task thread.
This would be much easier if I could store something non-serializeable in session scope. Storing things in application scope is beginning to sound like an extremely awkward work around. Can WebSession store things that are not serializable? I'm guessing not, since WebSession itself implements Serializable. From: Francois Meillet <francois.meil...@gmail.com> To: users@wicket.apache.org Date: 05/06/2014 08:06 AM Subject: Re: Application Scope You can use MyApp.get().setMetaData() and MyApp.get().getMetaData() François Meillet Formation Wicket - Développement Wicket Le 6 mai 2014 à 14:50, Richard W. Adams <rwada...@up.com> a écrit : > Are you referring to org.apache.wicket.Application? I don't see a > getTasksMap() method there. We use Wicket 1.4.17 & our company will not > allow us to upgrade to newer versions). If getTasksMap() is unavailable in > 1.4.17, could Application.getSharedResources() be used in a similar way? > > > > > From: Martin Grigorov <mgrigo...@apache.org> > To: "users@wicket.apache.org" <users@wicket.apache.org> > Date: 05/06/2014 07:26 AM > Subject: Re: Background Threading > > > > Hi, > > You can put the tasks in an application scoped structure (e.g. > MyApplication.get().getTasksMap()) and use a serializable key. > > Martin Grigorov > Wicket Training and Consulting > > > On Tue, May 6, 2014 at 2:11 PM, Richard W. Adams <rwada...@up.com> wrote: > >> Interesting approach. Our use case is more complex, as it runs a >> background task in a separate thread. Our task has three basic >> requirements. It must: >> >> 1. Be cancellable. >> >> 2. Report its outcome (success/failure/warning). >> >> 3. Report incremental progress. >> >> Our fundamental problem is not how to display the progress bar, it's how >> to determine the outcome of the background thread. That's an > unexpectedly >> a tough nut to crack. The vast majority of examples we've seen use the >> Runnable interface (which doesn't help us, as it can't be canceled or >> return a value), rather than Callable interface (which meets our needs, >> but doesn't seem to play well with Wicket) >> >> >> >> >> From: Colin Rogers <colin.rog...@objectconsulting.com.au> >> To: "users@wicket.apache.org" <users@wicket.apache.org> >> Date: 05/05/2014 08:14 PM >> Subject: RE: Progress Bar >> >> >> >> There is a pretty nifty, jquery based progress bar, in wicket-jquery-ui >> library... >> >> > http://www.7thweb.net/wicket-jquery-ui/progressbar/DefaultProgressBarPage >> >> Cheers, >> Col. >> >> -----Original Message----- >> From: Richard W. Adams [mailto:rwada...@up.com] >> Sent: Tuesday, 6 May 2014 3:19 AM >> To: users@wicket.apache.org >> Subject: Progress Bar >> >> We have a requirement to implement a progress bar for long-running > server >> operations. We can't use the code at >> https://github.com/wicketstuff/core/wiki/Progressbar, because it doesn't >> meet our corporate user interface look-and-feel standards. >> >> So, we started our own implementation. Our test page contains these >> methods below (the TestExecutor below class implements >> Callable<ExecutorResult>). >> >> >> > //---------------------------------------------------------------------------------------------- >> private Component createButton() { >> return new AjaxButton("start-button") { >> private static final long serialVersionUID = -1; >> >> @Override protected void onSubmit(final > AjaxRequestTarget >> ajax, final Form<?> form) { >> >> final ExecutorService service = Executors. >> newSingleThreadExecutor(); >> try { >> final ProgressBarTestPage page = >> ProgressBarTestPage.this; >> final TransactionData data = new >> TransactionData (page.getId(), false); >> final TestExecutor executor = new >> TestExecutor(data, getPermissions()); >> >> executor.addListener(page); // > Request >> notification when done >> future = service.submit(executor); // >> Begin execution >> progressBarUpdater.start(ajax, > executor); >> // Start polling for progress >> >> } catch (final Exception ex) { >> throw new RuntimeException(ex); >> } >> service.shutdown(); // Terminate gracefully >> (VM probably >> } // won't exit if we fail to do > this) >> }; >> } >> >> > //---------------------------------------------------------------------------------------------- >> /** >> Observer Pattern method to let us know when the task is done so we > can >> check how things went. >> */ >> @Override public void executionComplete(final EnmCallableExecutor >> executor) { >> >> try { >> if (!future.isCancelled()) { // >> Unless execution was canceled >> final ExecutorResult result = future.get(); // >> Get the outcome >> System.out.println(result); >> /* >> * TODO: Show success or error message >> */ >> } >> } catch (final Exception ex) { >> ex.printStackTrace(); >> } >> } >> >> The ProgessBarUpdater class has this method: >> >> >> > //---------------------------------------------------------------------------------------------- >> /** >> * Displays the progress bar & begins the polling. We don't start > the >> polling until >> * explicitly told to do, for efficiency purposes. >> * @param ajax The Ajax request wrapper. >> * @param reporter The object to query for progress data. >> */ >> public void start(final AjaxRequestTarget ajax, final ProgressReporter >> reporter) { >> >> add(new AjaxSelfUpdatingTimerBehavior(Duration.seconds(2)) { >> private static final long serialVersionUID = 1L; >> >> @Override protected void onPostProcessTarget(final >> AjaxRequestTarget ajax) { >> >> final Progress progress = > reporter.getProgress(); >> final String script = // Build >> script to update >> ProgressScript.build(progress); // >> progress bar >> ajax.appendJavascript(script); >> if (progress == null) { // If >> operation is finished >> final ProgressBarUpdater updater = >> ProgressBarUpdater.this; >> updater.remove(this); // >> Stop timer to prevent >> ajax.addComponent(updater); // > pointless >> polling >> } >> } >> }); >> ajax.addComponent(this); >> } >> >> The page also contains a Future object so we can check the result after >> the thread finishes: >> >> private Future<ExecutorResult> future; >> >> __________________________________________ >> >> Having said all that, here's the problem: When I click the page's > button, >> Wicket throws this error: >> >> Unable to serialize class: java.util.concurrent.FutureTask >> >> The FutureTask object, I believe, is coming from the service.submit call >> whose return value we store in our Future variable. >> >> Does anyone know how to get around this roadblock? >> >> >> >> ** >> >> This email and any attachments may contain information that is >> confidential and/or privileged for the sole use of the intended > recipient. >> Any use, review, disclosure, copying, distribution or reliance by > others, >> and any forwarding of this email or its contents, without the express >> permission of the sender is strictly prohibited by law. 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