[Paraview] How to plug into paraview his own writer ?

[houssen]

I followed 2 tutorials 
(http://www.itk.org/Wiki/ParaView/Plugin_HowTo#Writing_Plugins, 
http://www.kitware.com/media/html/WritingAParaViewReaderPlug-in.html) 
but I feel like I missed some steps : this is not working.

I need to "catch" data (I can see in 2D/3D paraview viewer) to write 
them into a specific file format. I am looking for the minimal 
(simplest) way to do this : the only writer input is the file name, then 
I would like to understand how to "get data from" paraview (from inside 
a vtk object I guess ?), then I just will have to do the easy part which 
is to write data to a specific format.

My understanding is that, first I need a CMakeLists.txt like :
~> more CMakeLists.txt
FIND_PACKAGE ( ParaView REQUIRED )
INCLUDE ( ${PARAVIEW_USE_FILE} )
ADD_PARAVIEW_PLUGIN ( myWriter "1.0" SERVER_MANAGER_XML myWriter.xml
SERVER_MANAGER_SOURCES myWriter.cpp )

In the same directory, I need a (minimal) myWriter.xml file that looks
like :
~> more myWrite.xml
  <ServerManagerConfiguration>
  <ProxyGroup name="WRITERS">
  <SourceProxy name="MYWRITER" class="MYWRITER" label="my writer">
  <Documentation short_help="my own writer"/>
  <InputProperty>
  <StringVectorProperty name="FileName" command="SETFILENAME" 
number_of_elements="1"/>
  </InputProperty>
  <Hints>
  <WriterFactory extensions="mw" file_description="my written file"/>
  </Hints>
  </SourceProxy>
  </ProxyGroup>
</ServerManagerConfiguration>
My understanding is that somehow the xml subscribes my for a specific 
callback I am called back on the "save data" button is cliked in the 
GUI.

Still, in this same directory, I have myWriter.cpp and myWriter.hpp :
how to implement them ?
1. The myWriter class must define and implement a SetFileName method 
because of the <StringVectorProperty> xml tag in myWriter.xml : right ? 
wrong ?
    This is the file name (including file path) one sets in the GUI : 
right ? wrong ?
2. myWriter is supposed to derive from another class : which one ? 
where to find it ?
3. How the myWriter implementation will "catch" data in paraview ? 
Which method to override / re-implement ?
    When I am called from paraview (triggered by the click on "save 
data" button), I guess I am called on a specific method 
"myWriter::cbMethod ( vtkXXX * pDataInParaviewViewer )"
   What is this method ?

Also, at this step, I export 
PV_PLUGIN_PATH=/mnt/users/houssen/Documents/solve-rel/paraview. When I 
run paraview and use the "save data" button I get this :
Generic Warning: In 
/.../Programs/ParaView/ParaView-v4.3.1-source/ParaViewCore/ServerManager/Core/vtkSMWriterFactory.cxx, 
line 135
writers : myWriter has no input property.
... But I have an <InputProperty> tag in the xml : what's wrong ?

Can somebody help me on this ?

Franck

Note : I run Ubuntu and paraview-4.3