[vtkusers] java memory

[Jonathan Morra]

Thanks.  Since I'm using vtkJavaGarbageCollector I'm already using
vtkGlobalJavaHash.GC();.  The main questions that I currently still need
answered are here
1.  hould I have to call System.gc(); and System.runFinalization();
frequently with VTK+Java?  It appears the memory is managed better when
calling these lines every time vtkGlobalJavaHash.GC() is called, but I don't
know if this is necessary.
2.  Is it ok to reuse Java variables?  Such as

vtkImageData image = filter.GetOuput();

// Do Stuff

image = filter2.GetOuput();

3.   Is it OK to move around java objects without an intermediate reference?
 Such as
image1.SetOutputSpacing(image2.GetSpacing());

Thanks for all your help!

On Mon, Mar 28, 2011 at 6:54 PM, Sebastien Jourdain <
sebastien.jourdain at kitware.com> wrote:

> Hi Jonathan,
>
> Did I say Java reference count ? I think I was talking about the C++
> layer that use reference count to delete unused VTK object. Depending
> on the way you are doing things in Java, you can messed up that count
> and therefore the vtkObject never get deleted as the C++ layer thinks
> that reference is still used somewhere else.
>
> Regarding some of your questions (please ask them again if I miss some
> in a single mail) here are some concept that are behind.
>
> If you call a method GetXXX() which return an object that has been
> defined in the VTK library (in the C++ layer), you must use an
> intermediate variable before assigning it to another SetXXX() vtk
> object method.
> Remarque: Java method name should have there first letter in lower
> case which is not the case for the VTK ones. That could help to know
> when you should do what.
>
> Moreover, to clear the VTK object associated to the Java ones, you do
> need to call
>
> vtkGlobalJavaHash.GC();
>
> Otherwise they never get released. This is to prevent thread crash in
> using VTK inside a multi-threaded java application. I mean by that, it
> is the responsibility of the developer to call that method at the
> right time as VTK is not thread safe.
>
> Good luck,
>
> Seb
>
>
> On Mon, Mar 28, 2011 at 9:24 PM, Jonathan Morra <jonmorra at gmail.com>
> wrote:
> > Sorry for the barrage of questions, but I am really excited to get this
> > working.  Is it OK to move around java objects without an intermediate
> > reference?  Such as
> > image1.SetOutputSpacing(image2.GetSpacing());
> >
> > On Mon, Mar 28, 2011 at 6:18 PM, Jonathan Morra <jonmorra at gmail.com>
> wrote:
> >>
> >> Also, is it ok to reuse Java variables?  Such as
> >> vtkImageData image = filter.GetOuput();
> >> // Do Stuff
> >> image = filter2.GetOuput();
> >>
> >>
> >> On Mon, Mar 28, 2011 at 5:19 PM, Jonathan Morra <jonmorra at gmail.com>
> >> wrote:
> >>>
> >>> Should I have to call System.gc(); and System.runFinalization();
> >>> frequently with VTK+Java?
> >>>
> >>> On Mon, Mar 28, 2011 at 5:05 PM, Jonathan Morra <jonmorra at gmail.com>
> >>> wrote:
> >>>>
> >>>> OK, can you explain what you mean by Java reference count?  Here's
> some
> >>>> example code that doesn't seem to be working well.  Every time I run
> it I
> >>>> seem to accumulate memory I don't want.  Also, I'm using
> >>>> vtkJavaGarbageCollector
> >>>>         vtkLinearExtrusionFilter extruder = new
> >>>> vtkLinearExtrusionFilter();
> >>>>         extruder.SetInput(data);
> >>>>         extruder.Update();
> >>>>         vtkPolyData extruderOutput = extruder.GetOutput();
> >>>>         vtkPolyDataToImageStencil pol2Stenc = new
> >>>> vtkPolyDataToImageStencil();
> >>>>         pol2Stenc.SetTolerance(0);
> >>>>         pol2Stenc.SetInput(extruderOutput);
> >>>>         pol2Stenc.SetInformationInput(binaryOrgan);
> >>>>         pol2Stenc.Update();
> >>>>         vtkImageStencilData pol2StencOutput = pol2Stenc.GetOutput();
> >>>>         vtkImageStencil stencil = new vtkImageStencil();
> >>>>         stencil.SetInput(binaryOrgan);
> >>>>         stencil.ReverseStencilOn();
> >>>>         stencil.SetStencil(pol2StencOutput);
> >>>>         stencil.Update();
> >>>>         final vtkImageData stencilOutput = stencil.GetOutput();
> >>>>
> >>>>             return stencilOutput;
> >>>> On Mon, Mar 28, 2011 at 4:58 PM, Sebastien Jourdain
> >>>> <sebastien.jourdain at kitware.com> wrote:
> >>>>>
> >>>>> Hi Jonathan,
> >>>>>
> >>>>> You should start by reading that thread.
> >>>>>
> >>>>> http://markmail.org/thread/k3u7gvsqwkocwfo5
> >>>>>
> >>>>> Seb
> >>>>>
> >>>>> On Mon, Mar 28, 2011 at 7:44 PM, Jonathan Morra <jonmorra at gmail.com>
> >>>>> wrote:
> >>>>> > I've been working with Java for a while now and can't seem to get
> my
> >>>>> > memory
> >>>>> > usage under control.  Is there anyone out there who's an expert in
> >>>>> > VTK+Java
> >>>>> > or at the very least has dealt with extensive memory usage in Java
> >>>>> > with VTK
> >>>>> > that could give me some advice or some reading material.
> >>>>> > Thanks
> >>>>> > _______________________________________________
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> >>>>> >
> >>>>> > Visit other Kitware open-source projects at
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> >>>>> >
> >>>>> > Please keep messages on-topic and check the VTK FAQ at:
> >>>>> > http://www.vtk.org/Wiki/VTK_FAQ
> >>>>> >
> >>>>> > Follow this link to subscribe/unsubscribe:
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> >>>>> >
> >>>>> >
> >>>>
> >>>
> >>
> >
> >
>
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