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?
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