I'm attempting to create a bare bones app for use in developing a plugin. I don't need a workbench.
Below the title1 dialog will show, but the title2 never does.
What needs to be done in order for the 2nd one to be shown?
public class BareBonesApp extends AbstractApplication
{
public Object start(IApplicationContext context) throws Exception
{
Display display = PlatformUI.createDisplay();
MessageDialog.openWarning(null, "title1", "message1");
display.asyncExec(new Runnable()
{
public void run()
{
MessageDialog.openWarning(null, "title2", "message2");
}
});
return null;
}
}
Display has different queues for runnables that should run sync, async or in a specifc time (Display.timerExec). When Display.readAndDispatch has dispatched all events, first the runnables in the sync-queue are executed, then the async-queue is emptied and after that the due timerExec runnables are executed.
The only difference between Display.syncExec and Display.asyncExec is that the syncExec method waits for the runnable to be executed by the Display thread. Display.asyncExec simply queues the runnable and goes on.
So if "title2" never appears, I asume your application does not run the Display loop:
Display display = new Display(); // this thread should be the only one that creates a display instance
while (someCondition) {
if (!display.readAndDispatch())
display.sleep();
}
Related
I have a slightly odd issue and unfortunately it's not one I can easily write a standalone class for.
Within my application I have a TableView (on a tab) which is clickable. Clicking on a row in this TableView opens a new Tab with a data relating to the clicked row in a new TableView.
The TableViews are bound to a custom class that extends ModifiableObservableListBase. This allows a Scrollbar to be used to request new data from the server based on the top and bottom rows of the viewport.
This all works well.
I also have a Service in my subclass of ModifiableObservableListBase that is used to improve the rendering of data under high load. It uses a LinkedBlockingQueue and countDownLatch so that only most recent view is updated to the UI preventing unnecessary redraws. Using the following:
setAll(list);
This also works well.
So far so good!
What I've noticed is that when I open and close these tabs multiple times (no fixed number), at some point the TableView will stop updating with data. The data is requested from the server and received but the Service which is used to control how data is added to the ModifiableObservableListBase fails to move out of the SCHEDULED state. This means that the Task that has been created never runs. I'm struggling to see why this would work correctly x times and then stop working.
Any help would be really welcomed, sorry I don't have a standaone application that replicates this issue. I will try to recreate it.
The following Service is constructed in the constructor of my subclass of ModifiableObservableListBase which is constructed each time a new tab(including the corresponding TableView which is bound to the ModifiableObservableListBase ) is added to the UI.
Service upDateService = new Service() {
#Override
protected Task createTask() {
//when the code fails it still calls to here.
return new Task() {
#Override
protected Object call() throws Exception {
//when the code fails it doesn't call the call() method
while (true) {
List<T> list = updateQueue.take();
updateLatch = new CountDownLatch(1);
//now put on the FX Application Thread
Platform.runLater(() -> {
if (list.size() > 0 && list.get(0) instanceof TableStructure) {
totalRowCount.set(((TableStructure) list.get(0)).getTotalDbRowCount());
}
setAll(list);
updateLatch.countDown();
});
try {
updateLatch.await(1, TimeUnit.MINUTES);
updateLatch = null;
}
catch (InterruptedException ex) {
ex.printStackTrace();
}
}
}
};
}
};
upDateService.start();
I am performing a long running operation and showing message dialog as "fetching details" and closing the same once the operation is performed.
try{
MessageDialog dialog = new MessageDialog(Display.getDefault().getActiveShell(), "Information", null, "Fetching Details...", MessageDialog.NONE , new String[] {}, -1);
dialog.setBlockOnOpen(false);
dialog.open();
//Schedule long Running operations
} finally{
dialog.close()
}
If the operation takes more time, dialog is showing not responding (Title changes to "Information (Not Responding)").
How can avoid the not responding status ?
You must not run long operations in the UI thread. Doing so will block the thread until they finish and the UI will become unresponsive.
Run your operations in a background thread, or an Eclipse Job or even a Java 8 CompleteableFuture.
Use the Display asyncExec in your background code to update the UI as required.
Another alternative is to use ProgressMonitorDialog:
ProgressMonitorDialog dialog = new ProgressMonitorDialog(shell);
try {
dialog.run(true, true, new IRunnableWithProgress() {
#Override
public void run(IProgressMonitor monitor) {
monitor.beginTask("Task name", IProgressMonitor.UNKNOWN);
try {
// TODO your long running code
// TODO check monitor.isCanceled() as often as possible
}
finally {
monitor.done();
}
}
});
}
... catch exceptions
Is there a way to capture the event when a stage or screen gets focus? I tried to use focusedProperty but I guess that is used only when initially the stage/screen gets shown.
I am not sure if essentially I have to capture, WindowEvent.WINDOW_SHOWN event. I did try the following piece of code in my application, but there is probably a mistake.
stage.addEventFilter(WindowEvent.WINDOW_SHOWN, new EventHandler<WindowEvent>()
{
#Override
public void handle(WindowEvent window)
{
System.out.println("EventFilter :: Window shown");
}
});
stage.addEventHandler(WindowEvent.WINDOW_SHOWN, new EventHandler<WindowEvent>()
{
#Override
public void handle(WindowEvent window)
{
System.out.println("EventHandler :: Window shown");
}
});
None of the sysouts is shown when I execute the program.
Another part to the same problem is whether the event handler would get triggered if lets say I minimize and maximize the application(i.e the application again got focus) or I lock my machine and unlock it?
I have a working ProgressMonitorDialog, but I want to make sure that I am setting it up correctly.
First the Code:
Method to create Dialog
public void startProgressBar() {
try {
new ProgressMonitorDialog(getShell()).run(true, true,
new ProgressBarThread());
}
catch (InvocationTargetException e) {
MessageDialog.openError(getShell(), "Error", e.getMessage());
}
catch (InterruptedException e) {
MessageDialog.openInformation(getShell(), "Cancelled", e.getMessage());
}
}
Class File
class ProgressBarThread implements IRunnableWithProgress {
private static final int TOTAL_TIME = 1000;
public ProgressBarThread() {
}
public void run(IProgressMonitor monitor) throws InvocationTargetException,InterruptedException {
monitor.beginTask("Creating PDF File(s): Please wait.....", IProgressMonitor.UNKNOWN);
for (int total = 0; total < TOTAL_TIME ; total++) {
Thread.sleep(total);
monitor.worked(total);
if (total == TOTAL_TIME / 2) monitor.subTask("Please be patient... Operation should finish soon.");
}
monitor.done();
}
}
Method that calls the ProgressBar and runs a Pdf file creation Operation
private void startSavePdfOperation() {
Display.getDefault().asyncExec(new Runnable() {
public void run() {
startProgressBar();
}
});
saveOp = new AplotSaveOperation(appReg.getString("aplot.message.SAVETOPDF"), "PDF", session);
saveOp.addOperationListener(new MyOperationListener(this) {
public void endOperationImpl() {
java.io.File zipFile = null;
try {
AplotSaveResultsParser.SaveResult saveResults = saveOp.getSaveResults();
if (saveResults != null) {
ETC..... ETC......
Questions:
Being the ProgressMonitorDialog is a GUI, it needs to be executed in a
Display.getDefault().asyncExec?
If the ProgressMonitorDialog is running in a separate thread, how does it know to close when the operation is finsihed?
Is there any relationship between the progressbar and the operation?
I am correct in assuming that the for loop in the ProgressBarThread class is basically the timer that keeps the monitor open?
Is there a way to increase the speed of the ProgressMonitorDialog's indicator, also can you remove the cancel button?
This is what I am thinking is happening currently.
I am starting the progress bar just before I start the PDF Operation Listener
See startSavePdfOperation() Above
The progress bar is running as unknown, but using a for loop to keep the progress bar dialog open, while the operation is running on a thread in the background.
See Class ProgressBarThread above
When the PDF operation completes the listener operation class closes the base GUI dialog.
public void endOperation() {
try {
endOperationImpl();
}
finally {
Display.getDefault().asyncExec(new Runnable() {
public void run() {
w.getShell().setCursor(new Cursor(Display.getCurrent(), SWT.CURSOR_ARROW));
w.recursiveSetEnabled(getShell(), true);
w.getShell().setEnabled(!getShell().getEnabled());
w.close();
}
});
}
}
I am not sure what is happening to the ProgressBarThread monitor?
Is this Possible?
When the PDF Operation starts, the ProgressMonitorDialog opens and starts the indicator. OK with keeping it unknown.
When the PDF Operation completes, the monitor closes, then the base Dialog
I am just wanting to open progress bar dialog that will inform the user that their request is working in the background.
As stated the above code works, but I am afraid by letting the closing of Base GUI, destroy my Progress Thread and Monitor is not good practice.
First of all, in your ProgressBarThread#run() you should use monitor.worked(1). You don't need to set the total worked but increment it by the amount of work done, since the last time it was called.
Q1. Yes it needs to be executed in the display thread
Q2. Normally the work that needs to be done is actually performed in the runnable that is passed to the progress monitor dialog so that you can accurately report the amount of progress made. So your operation (if it is a synchronous call) should be called from within ProgressBarThread#run() so that you call monitor.worked(1) only when one file processing is complete.
Q3. What kind of operation are you running, perhaps it already supports showing progress bar, and you just need to invoke the right API. Is it an IUndoableOperation?
Q4. As I said this approach is problematic because you can never accurately report the progress and close the dialog only when the operation is completed. But if this is the only choice you have, then you can just save the monitor reference somewhere so that it is accessible to the other thread. Once monitor.done() is called, your ProgressBarThread#run() should return, the dialog will close.
Q5. You can remove the cancel button by passing the correct parameter to ProgressMonitorDialog#run(..):
new ProgressMonitorDialog(getShell()).run(true, false, new ProgressBarThread());
For the rest of the questions I can better answer if I know what kind of operation (what API) you are using.
I was hoping that Display.timerExec(int,Runnable) was much the same as Display.asyncExec(Runnable) but with the specified delay. However it appears that Display.timerExec can only be executed on the GUI thread, as its 1st line is a call to checkDevice(). This throws an exception if you're not running in a GUI thread.
Can anyone suggest a means to using Display.asyncExec() but with a delay preceding execution?
You can first switch to the GUI thread with asyncExec, then schedule a timer action with timerExec. These two methods are similar in that they both execute some action, but asyncExec only switches thread, timeExec only schedules an action for the GUI thread.
display.asyncExec(() -> display.timerExec(100, () -> doThings()));
This uses lambda expressions, which where introduced in Java 8.
With Java 7 or earlier one has to write it with anonymous classes like this:
display.asyncExec(new Runnable() {
public void run() {
display.timerExec(100, new Runnable() {
public void run() {
doThings();
}
});
}
});