Re: Java multi-thread and model Observer

Hi Sébastien,

Thanks for your response.

Actually, I don't understand why I still have the use of a Timer, neither.
But the point is that if I put the panel3d.resetCamera() command outside
the Timer, it doesn't work :-(.

Hope I can figure out why soon and any hint on this purpose will be really
appreciated.

Anyway thanks again for your time.

jMax




Le ven. 22 févr. 2019 à 19:09, Sebastien Jourdain <
[email protected]> a écrit :

> Hi Jean-Max,
>
> I'm not sure to follow all the details of your implementation or why you
> still have the use of a Timer.
> The only things that you need to worry about is that any rendering action
> (addActor/removeActor, update when actor connected, render) MUST BE in the
> EDT.
>
> HTH,
>
> Seb
>
> On Thu, Feb 21, 2019 at 2:19 AM Jean-Max Redonnet <[email protected]>
> wrote:
>
>> Hello everyone !
>>
>> I'm using vtk throught its java wrapper and I'm setting up a versatile
>> viewer that can display an existing model and update display when this
>> model is updated (and it will be continously updated).
>>
>> My Model is built around few classes: VtkObject that is the ancestor of
>> many other classes like VtkSurface, VtkCurve, etc... and VtkModel that
>> basically contains a list of VtkObjects and maintain Listeners. All these
>> classes are of my own (please note uppercase "V" on VtkObject)
>>
>>
>> public class VtkObject{
>>     protected final PropertyChangeSupport pcs = new
>> PropertyChangeSupport(this);
>>     protected List<vtkActor> actors = new ArrayList<vtkActor>();
>>     ...
>> }
>>
>> public class VtkSurface extends VtkObject {
>>     private vtkActor surfActor;
>>     ...
>> }
>>
>> public class VtkModel implements PropertyChangeListener{
>>     protected List<VtkObject> objects;
>>     protected PropertyChangeSupport support;
>>     ...
>> }
>>
>> For the viewer itself I wrote a VtkPanel that is mostly inspired by the
>> example provided by Sébastien Jourdain (
>> https://github.com/Kitware/VTK/blob/master/Wrapping/Java/vtk/sample/Demo.java
>> )
>>
>> I just make this panel model-aware implementing PropertyChangeListener:
>>
>>     @Override
>>     public void propertyChange(PropertyChangeEvent evt) {
>>         if (evt.getPropertyName() == "AddedObject") {
>>             System.out.println("Added Object");
>>             VtkObject o = (VtkObject) evt.getNewValue();
>>             if(o.getActors().size()>0)
>>                 exec.submit(new PipelineBuilder(o));
>>         }
>>         if (evt.getPropertyName() == "UpdatedObject") {
>>             System.out.println("Updated Object");
>>             VtkObject o = (VtkObject) evt.getNewValue();
>>             if(o.getActors().size()>0)
>>                 exec.submit(new PipelineBuilder(o));
>>         }
>>     }
>>
>> and slithly modify PipelineBuilder to make it able to manage VtkObjects
>> that may contain several vtkActors
>>
>>     public class PipelineBuilder implements Callable<vtkActor> {
>>         private int counter;
>>         private List<vtkActor> actors;
>>
>>         public PipelineBuilder(VtkObject o) {
>>             actors = o.getActors();
>>             counter = 0;
>>         }
>>
>>         @Override
>>         public vtkActor call() throws Exception {
>>             counter++;
>>             if (counter < actors.size() + 1)
>>                 return actors.get(counter - 1);
>>             return null;
>>         }
>>     }
>>
>> Also, workers are setup to continously search for new actors:
>>
>>     private void setupWorkers() {
>>         // Add actor thread: Consume the working queue and add the actor
>> into
>>         // the render inside the EDT thread
>>         final AddActorRunnable adderRunnable = new AddActorRunnable();
>>         adderRunnable.setRenderer(panel3d);
>>         new Thread() {
>>             public void run() {
>>                 while (true) {
>>                     try {
>>                         adderRunnable.setActor(exec.take().get());
>>                         SwingUtilities.invokeAndWait(adderRunnable);
>>                         panel3d.repaint();
>>                     } catch (InterruptedException e) {
>>                         return;
>>                     } catch (ExecutionException e) {
>>                         e.printStackTrace();
>>                     } catch (InvocationTargetException e) {
>>                         e.printStackTrace();
>>                     }
>>                 }
>>             };
>>         }.start();
>>     }
>>
>>
>> Here is the test class I use:
>>
>> public class TestVtkPanel {
>>     public VtkModel model;
>>
>>     public TestVtkPanel() {
>>         SwingUtilities.invokeLater(new Runnable() {
>>             public void run() {
>>                 model = getModel();
>>                 VtkPanel panel = new VtkPanel();
>>                 model.addPropertyChangeListener(panel);
>>
>>                 JButton exitBtn = new JButton("Quitter");
>>                 exitBtn.addActionListener(new ActionListener() {
>>
>>                     public void actionPerformed(ActionEvent e) {
>>                         System.exit(0);
>>                     }
>>                 });
>>                 JFrame f = new JFrame("Vtk Viewer");
>>                 f.getContentPane().setLayout(new BorderLayout());
>>                 f.getContentPane().add(panel, BorderLayout.CENTER);
>>                 f.getContentPane().add(exitBtn, BorderLayout.SOUTH);
>>
>>                 f.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
>>                 f.setSize(800, 600);
>>                 f.setVisible(true);
>>                 f.validate();
>>
>>                 panel.startWorking(model);
>>
>>                 new Thread(new Runnable() {
>>                     public void run() {
>>                         updateModel();
>>                     }
>>                 }).start();
>>
>>             }
>>         });
>>
>>     }
>>
>>
>>     ...
>>   }
>>
>>
>>
>> All this stuff works fine, but few questions remains.
>>
>> Is this way to do thing is the best for what I'm trying to achieve ? If a
>> vtk guru can give a look to my code, it would be gratefully appreciated.
>> Furthermore inside the VtkPanel constructor I tried to put the vtkPanel
>> panel3d outside of the Timer but that do not work.
>>
>>     new Timer(1000, new ActionListener() {
>>
>>             public void actionPerformed(ActionEvent e) {
>>                 if (nbSeconds++ < 1) {
>>                     panel3d.resetCamera();
>>                 }
>>                 // Run GC in local thread (EDT)
>>             ...
>>      }
>>
>> I can't figure out why. Any hint on this point may help me to understand
>> multithreading.
>>
>> Thanks for your help.
>>
>> jMax
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