Concurrent event in Graph: NoSuchElementException in GraphListeners

[victornoel]

Hi,

I have a Graph, Nodes and Edges that are concurrently modified.

Since the Graph is attached to a Viewer, GraphListeners is responsible of piping the events from the graph to the viewer.

Sometimes, when there are concurrent modification of the elements of the graph, I get the following exception:

java.util.NoSuchElementException
	at java.util.LinkedList.removeFirst(LinkedList.java:270)
	at java.util.LinkedList.remove(LinkedList.java:685)
	at org.graphstream.stream.SourceBase.manageEvents(SourceBase.java:872)
	at org.graphstream.stream.SourceBase.sendAttributeChangedEvent(SourceBase.java:810)
	at org.graphstream.util.GraphListeners.sendAttributeChangedEvent(GraphListeners.java:73)
	at org.graphstream.graph.implementations.AbstractEdge.attributeChanged(AbstractEdge.java:106)
	at org.graphstream.graph.implementations.AbstractElement.addAttribute(AbstractElement.java:544)
	at org.graphstream.graph.implementations.AbstractElement.setAttribute(AbstractElement.java:560)

I tried using Graphs.synchronizedGraph but it doesn't solve the problem, because this is not about concurrent modification of ONE element, but concurrent emission of events to theGraphListeners.

There seem to be no way to have this pipe behave correctly with concurrence.
Is there something I am missing or is this a bug?

[jeremy-boes]

We forgot to mention we are using v1.3.

[mdvx]

I am hitting the same issue, my background thread is replacing attributes on the Graph, which works fine until i hit this. Then the Graph stops updating on the screen.

[hichbra]

Hi,

Can you confirm that this problem still exists in Graphstream 2.0 ?
Also, to be able to work in that problem, can you provide a simple and self contained example ?

[jeremy-boes]

Could you upload 2.0 to Maven Central so I can test it?

[hichbra]

Graphstream 2 use jitpack.io, you can see how to use it in the readme.

[jeremy-boes]

A similar exception occurs with Graphstream 2.0 (gs-core 2.0.0-beta, gs-ui-swing 2.0-alpha)

Unfortunately, I'm unable to spend more time on this right now and provide a self-contained example.

Here's the complete stacktrace:

Exception in thread "AWT-EventQueue-0" java.util.ConcurrentModificationException
	at java.base/java.util.HashMap$HashIterator.nextNode(HashMap.java:1493)
	at java.base/java.util.HashMap$ValueIterator.next(HashMap.java:1521)
	at org.graphstream.ui.graphicGraph.StyleGroup$BulkIterator.next(StyleGroup.java:815)
	at org.graphstream.ui.graphicGraph.StyleGroup$BulkIterator.next(StyleGroup.java:772)
	at java.base/java.lang.Iterable.forEach(Iterable.java:74)
	at org.graphstream.ui.swing.renderer.StyleRenderer.render(StyleRenderer.java:92)
	at org.graphstream.ui.swing.renderer.StyleRenderer.render(StyleRenderer.java:67)
	at org.graphstream.ui.swing.SwingGraphRenderer.lambda$null$4(SwingGraphRenderer.java:242)
	at java.base/java.lang.Iterable.forEach(Iterable.java:75)
	at org.graphstream.ui.swing.SwingGraphRenderer.lambda$render$5(SwingGraphRenderer.java:240)
	at java.base/java.lang.Iterable.forEach(Iterable.java:75)
	at org.graphstream.ui.swing.SwingGraphRenderer.render(SwingGraphRenderer.java:239)
	at org.graphstream.ui.swing.SwingGraphRenderer.render(SwingGraphRenderer.java:96)
	at org.graphstream.ui.swing_viewer.DefaultView.render(DefaultView.java:251)
	at org.graphstream.ui.swing_viewer.DefaultView.paintComponent(DefaultView.java:179)
	at java.desktop/javax.swing.JComponent.paint(JComponent.java:1074)
	at java.desktop/javax.swing.JComponent.paintChildren(JComponent.java:907)
	at java.desktop/javax.swing.JComponent.paint(JComponent.java:1083)
	at java.desktop/javax.swing.JComponent.paintChildren(JComponent.java:907)
	at java.desktop/javax.swing.JComponent.paint(JComponent.java:1083)
	at java.desktop/javax.swing.JComponent.paintChildren(JComponent.java:907)
	at java.desktop/javax.swing.JComponent.paint(JComponent.java:1083)
	at java.desktop/javax.swing.JLayeredPane.paint(JLayeredPane.java:590)
	at java.desktop/javax.swing.JComponent.paintChildren(JComponent.java:907)
	at java.desktop/javax.swing.JComponent.paintToOffscreen(JComponent.java:5262)
	at java.desktop/javax.swing.RepaintManager$PaintManager.paintDoubleBufferedImpl(RepaintManager.java:1643)
	at java.desktop/javax.swing.RepaintManager$PaintManager.paintDoubleBuffered(RepaintManager.java:1618)
	at java.desktop/javax.swing.RepaintManager$PaintManager.paint(RepaintManager.java:1556)
	at java.desktop/javax.swing.RepaintManager.paint(RepaintManager.java:1323)
	at java.desktop/javax.swing.JComponent.paint(JComponent.java:1060)
	at java.desktop/java.awt.GraphicsCallback$PaintCallback.run(GraphicsCallback.java:39)
	at java.desktop/sun.awt.SunGraphicsCallback.runOneComponent(SunGraphicsCallback.java:78)
	at java.desktop/sun.awt.SunGraphicsCallback.runComponents(SunGraphicsCallback.java:115)
	at java.desktop/java.awt.Container.paint(Container.java:2002)
	at java.desktop/java.awt.Window.paint(Window.java:3940)
	at java.desktop/javax.swing.RepaintManager$4.run(RepaintManager.java:876)
	at java.desktop/javax.swing.RepaintManager$4.run(RepaintManager.java:848)
	at java.base/java.security.AccessController.doPrivileged(Native Method)
	at java.base/java.security.ProtectionDomain$JavaSecurityAccessImpl.doIntersectionPrivilege(ProtectionDomain.java:85)
	at java.desktop/javax.swing.RepaintManager.paintDirtyRegions(RepaintManager.java:848)
	at java.desktop/javax.swing.RepaintManager.paintDirtyRegions(RepaintManager.java:823)
	at java.desktop/javax.swing.RepaintManager.prePaintDirtyRegions(RepaintManager.java:772)
	at java.desktop/javax.swing.RepaintManager$ProcessingRunnable.run(RepaintManager.java:1890)
	at java.desktop/java.awt.event.InvocationEvent.dispatch(InvocationEvent.java:313)
	at java.desktop/java.awt.EventQueue.dispatchEventImpl(EventQueue.java:770)
	at java.desktop/java.awt.EventQueue$4.run(EventQueue.java:721)
	at java.desktop/java.awt.EventQueue$4.run(EventQueue.java:715)
	at java.base/java.security.AccessController.doPrivileged(Native Method)
	at java.base/java.security.ProtectionDomain$JavaSecurityAccessImpl.doIntersectionPrivilege(ProtectionDomain.java:85)
	at java.desktop/java.awt.EventQueue.dispatchEvent(EventQueue.java:740)
	at java.desktop/java.awt.EventDispatchThread.pumpOneEventForFilters(EventDispatchThread.java:203)
	at java.desktop/java.awt.EventDispatchThread.pumpEventsForFilter(EventDispatchThread.java:124)
	at java.desktop/java.awt.EventDispatchThread.pumpEventsForHierarchy(EventDispatchThread.java:113)
	at java.desktop/java.awt.EventDispatchThread.pumpEvents(EventDispatchThread.java:109)
	at java.desktop/java.awt.EventDispatchThread.pumpEvents(EventDispatchThread.java:101)
	at java.desktop/java.awt.EventDispatchThread.run(EventDispatchThread.java:90)

[hichbra]

Thank you for the confirmation, I will try to work on this issue

[victornoel]

@hichbra jitpack is missing the source artefacts for the latest versions, is there anyway for those to be available too?

[hichbra]

I'm sorry if I misunderstood your question, are you talking about javafx ? There no beta version released for the moment.

[victornoel]

@hichbra no, I'm talking about the maven source artefacts: https://maven.apache.org/plugin-developers/cookbook/attach-source-javadoc-artifacts.html

This is important when using a library that it is possible to explore its source code and not only depends on the binary jar.

[hichbra]

Indeed ! Can you open a new issue ? We will try to work around for the next release.

[victornoel]

@hichbra here it is: #336, thanks a lot :)

[hichbra]

A pull request is sended : #337
if you want to try it in your project for a feedback :

<dependency>
 	<groupId>com.github.hichbra</groupId>
 	<artifactId>gs-core</artifactId>
 	<version>Fix293Concurrent-SNAPSHOT</version>
 	<scope>compile</scope>
</dependency>

[victornoel]

@pigne sorry to disappoint, but I just tested with v2.0 (with the swing ui) and I still get the exception (but it seems it appears less often, while before it appeared every time).

Here is the current stacktrace:

java.util.NoSuchElementException
	at java.base/java.util.LinkedList.removeFirst(LinkedList.java:274)
	at java.base/java.util.LinkedList.remove(LinkedList.java:689)
	at org.graphstream.stream.SourceBase.manageEvents(SourceBase.java:841)
	at org.graphstream.stream.SourceBase.sendAttributeChangedEvent(SourceBase.java:825)
	at org.graphstream.util.GraphListeners.sendAttributeChangedEvent(GraphListeners.java:79)
	at org.graphstream.ui.graphicGraph.GraphicEdge.attributeChanged(GraphicEdge.java:216)
	at org.graphstream.graph.implementations.AbstractElement.setAttribute(AbstractElement.java:311)
	at org.graphstream.ui.graphicGraph.GraphicElement.setAttribute(GraphicElement.java:311)
	at org.graphstream.util.GraphListeners.edgeAttributeChanged(GraphListeners.java:166)
	at org.graphstream.ui.graphicGraph.GraphicGraph.edgeAttributeChanged(GraphicGraph.java:928)
	at org.graphstream.stream.SourceBase.sendAttributeChangedEvent(SourceBase.java:818)
	at org.graphstream.util.GraphListeners.sendAttributeChangedEvent(GraphListeners.java:79)
	at org.graphstream.graph.implementations.AbstractEdge.attributeChanged(AbstractEdge.java:105)
	at org.graphstream.graph.implementations.AbstractElement.setAttribute(AbstractElement.java:311)