I'm debugging some code that was written using a SwingWorker to perform a mix of numerical calculation and GUI update. The SwingWorker hangs with the following stack trace :
Full thread dump Java HotSpot(TM) Client VM (14.3-b01 mixed mode, sharing):
"SwingWorker-pool-3-thread-4" prio=6 tid=0x07fd7c00 nid=0x143c waiting on condition [0x0a33f000]
java.lang.Thread.State: TIMED_WAITING (sleeping)
at java.lang.Thread.sleep(Native Method)
at sum.ee.ui.modelviewer.ModelViewer$ModelAnimator.doInBackground(ModelViewer.java:940)
at sum.ee.ui.modelviewer.ModelViewer$ModelAnimator.doInBackground(ModelViewer.java:877)
at javax.swing.SwingWorker$1.call(SwingWorker.java:274)
at java.util.concurrent.FutureTask$Sync.innerRun(FutureTask.java:303)
at java.util.concurrent.FutureTask.run(FutureTask.java:138)
at javax.swing.SwingWorker.run(SwingWorker.java:313)
at java.util.concurrent.ThreadPoolExecutor$Worker.runTask(ThreadPoolExecutor.java:886)
at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:908)
at java.lang.Thread.run(Thread.java:619)
"SwingWorker-pool-3-thread-3" prio=6 tid=0x07fd7000 nid=0x11a8 waiting for monitor entry [0x0a2af000]
java.lang.Thread.State: BLOCKED (on object monitor)
at java.awt.Component.resize(Component.java:2044)
- waiting to lock <0x24b936a0> (a java.awt.Component$AWTTreeLock)
at java.awt.Component.setSize(Component.java:2035)
at java.awt.Component.resize(Component.java:2069)
at java.awt.Component.setSize(Component.java:2060)
at javax.swing.JViewport.setViewSize(JViewport.java:1038)
at javax.swing.ViewportLayout.layoutContainer(ViewportLayout.java:183)
at java.awt.Container.layout(Container.java:1421)
at java.awt.Container.doLayout(Container.java:1410)
at jsyntaxpane.components.LineNumbersRuler.updateSize(LineNumbersRuler.java:109)
at jsyntaxpane.components.LineNumbersRuler.removeUpdate(LineNumbersRuler.java:203)
at javax.swing.text.AbstractDocument.fireRemoveUpdate(AbstractDocument.java:243)
at jsyntaxpane.SyntaxDocument.fireRemoveUpdate(SyntaxDocument.java:118)
at javax.swing.text.AbstractDocument.handleRemove(AbstractDocument.java:608)
at javax.swing.text.AbstractDocument.remove(AbstractDocument.java:576)
at javax.swing.JEditorPane.setText(JEditorPane.java:1493)
at sum.ee.ui.SourceCodePanel.clearSourcePane(SourceCodePanel.java:256)
at sum.ee.ui.SourceCodePanel.access$100(SourceCodePanel.java:47)
at sum.ee.ui.SourceCodePanel$1.stateChanged(SourceCodePanel.java:209)
at sum.ee.ui.VisualizationAggregator.fireStateChanged(VisualizationAggregator.java:300)
at sum.ee.ui.VisualizationAggregator.update(VisualizationAggregator.java:97)
at sum.ee.ui.modelviewer.ModelViewer$ModelAnimator.doInBackground(ModelViewer.java:918)
at sum.ee.ui.modelviewer.ModelViewer$ModelAnimator.doInBackground(ModelViewer.java:877)
at javax.swing.SwingWorker$1.call(SwingWorker.java:274)
at java.util.concurrent.FutureTask$Sync.innerRun(FutureTask.java:303)
at java.util.concurrent.FutureTask.run(FutureTask.java:138)
at javax.swing.SwingWorker.run(SwingWorker.java:313)
at java.util.concurrent.ThreadPoolExecutor$Worker.runTask(ThreadPoolExecutor.java:886)
at java.util.concurrent.ThreadPoolExecutor
$Worker.run(ThreadPoolExecutor.java:908) at java.lang.Thread.run(Thread.java:619)
My understanding is that GUI work should not be done inside of doInBackground(), but rather in done(). I performed a naive experiment where I moved all of the code in doInBackground() into done() and it still didn't work. Is there any tips that folks can give me on what I can do to root cause this issue? The code looks like this :
protected Void doInBackground() {
isAnimating = true;
resetButtonBackgrounds();
backgroundColor = new Color(175, 255, 175); // Soft Green
JToggleButton b = null;
for (final int index : modelIndices) {
if (index == modelIndices.get(modelIndices.size() - 1)) {
backgroundColor = defaultBackgroundColor;
}
if (!keepTrace) {
// Resetting the backgrounds is necessary to have
// individual display of the changing elements due to
// the fact that there can be multiple nodes per
// source line. The reset works in combination
// with updating from ModelViewer.this (as opposed
// to the 'this' of ModelAnimator instances) due
// to not sending an event to itself. Furthermore,
// if the event was sent from ModelAnimator, the model
// indices are recalculated, causing a jump when multiple
// element source lines are encountered.
resetButtonBackgrounds();
}
aggregator.modelIndex(index);
aggregator.update(ModelViewer.this);
b = getButtonByIndex(index);
scrollRectToVisible(b.getBounds());
ModelViewer.this.repaint();
try {
StaticTools.sleepAtLeast(sleepTimeMilliseconds);
} catch (final InterruptedException ex) {
// continue with thread
}
}
isAnimating = false;
if ( b != null) {
Color orig = b.getBackground();
Color blink = Color.PINK;
Color current = orig;
for (int i = 0; i < 100; i++) {
try {
Thread.sleep(100);
} catch (InterruptedException ex) {
}
if (current == orig) {
current = blink;
} else {
current = orig;
}
b.setBackground(current);
ModelViewer.this.repaint();
}
}
return null;
}
The other clue is that there are two SwingWorker threads that execute. Can they be running the same thread?
UPDATE: Here is the code that executes the SwingWorker :
public final void animate(final long delayBetweenUpdatesMilliseconds, final List modelIndices, final boolean keepTrace, final List propertyChangeListeners) {
ModelAnimator modelAnimator =
new ModelAnimator(delayBetweenUpdatesMilliseconds, modelIndices,
keepTrace);
for (final PropertyChangeListener listener : propertyChangeListeners) {
modelAnimator.addPropertyChangeListener(listener);
}
modelAnimator.execute();
}