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 &amp; 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?
>
>
>
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