[jgrapht-users] a problem with visualization of graph

[Amirali S. <ami...@gm...>]

Hello everyone,

I am using JgraphT for a project. I encountered to a bug which I couldn't
solve it yet, so any help is greatly appreciated :).
I have a randomly created graph consisting of almost 100 nodes and 2000
edges. Concisely, my code is adding/eliminating some edges during the
execution. I am using JGraphModelAdaptor.class to visualize the graph by
Jgraph. Interestingly, I get the following exception during the execution of
code:
Exception in thread "main" java.lang.NullPointerException
at org.jgraph.graph.EdgeRenderer.createShape(Unknown Source)
at org.jgraph.graph.EdgeView.getShape(Unknown Source)
at org.jgraph.graph.EdgeRenderer.getPaintBounds(Unknown Source)
at org.jgraph.graph.EdgeRenderer.getBounds(Unknown Source)
at org.jgraph.graph.EdgeView.getBounds(Unknown Source)
at org.jgraph.JGraph.getCellBounds(Unknown Source)
at org.jgraph.JGraph.getCellBounds(Unknown Source)
at
org.jgraph.plaf.basic.BasicGraphUI$GraphSelectionHandler.valueChanged(Unknown
Source)
at org.jgraph.graph.DefaultGraphSelectionModel.fireValueChanged(Unknown
Source)
at org.jgraph.graph.DefaultGraphSelectionModel.notifyCellChange(Unknown
Source)
at org.jgraph.graph.DefaultGraphSelectionModel.setSelectionCells(Unknown
Source)
at org.jgraph.JGraph.setSelectionCells(Unknown Source)
at org.jgraph.plaf.basic.BasicGraphUI$GraphModelHandler.graphChanged(Unknown
Source)
at org.jgraph.graph.DefaultGraphModel.fireGraphChanged(Unknown Source)
at org.jgraph.graph.DefaultGraphModel$GraphModelEdit.execute(Unknown Source)
at org.jgraph.graph.DefaultGraphModel.insert(Unknown Source)
at
org.jgrapht.ext.JGraphModelAdapter.internalInsertCell(JGraphModelAdapter.java:819)
at
org.jgrapht.ext.JGraphModelAdapter.handleJGraphTAddedEdge(JGraphModelAdapter.java:681)
at
org.jgrapht.ext.JGraphModelAdapter$JGraphTListener.edgeAdded(JGraphModelAdapter.java:1086)
at
org.jgrapht.graph.DefaultListenableGraph.fireEdgeAdded(DefaultListenableGraph.java:317)
at
org.jgrapht.graph.DefaultListenableGraph.addEdge(DefaultListenableGraph.java:168)
at simulator.Network.connect(Network.java:39)
at simulator.Simulator.processMessages(Simulator.java:257)
at simulator.Simulator.messagesWorker(Simulator.java:178)
at simulator.Simulator.run(Simulator.java:311)
at java.lang.Thread.run(Unknown Source)
at simulator.Simulator.main(Simulator.java:339)

Some interesting issues according to this bug are:

1 - I don't have this bug in creation of graph - to my understanding, the
edges in jgrapht are added to jgraph with  *handleJGraphTAddedEdge* method.
This method has been used in creation of graph(in constructor of
JGraphModelAdaptor), and  when the new edge is added to jgrapht (in *
edgeAdded* method). Surprisingly, I am getting this bug just when the graph
is changing during the execution of code, not in creation of graph.
2 - If I change the parameters of graph(number of nodes and edges) which
results in less numbers of deletions and additions of edges during the
execution of code, I will not get this bug...

I would greatly appreciate it if anyone help me in this regard,
All the best,
Amirali