[Insight-developers] DisconnectSource calls Modified()

[Julien Jomier]

Jim, pipeline gurus,

I noticed some strange behavior while running this code:

[snip]

    {
    typedef itk::ImageFileReader<Image3DType> ImageReaderType;
    ImageReaderType::Pointer imageReader = ImageReaderType::New();
    imageReader->SetFileName(IMAGEPATH);
    imageReader->Update();
    m_Image3D = imageReader->GetOutput();
    std::cout << m_Image3D->GetMTime() << std::endl;
    }
  std::cout << m_Image3D->GetMTime() << std::endl;

[snip]

The two GetMTime() returned are different. Looking at the DataObject class I
found that DataObject::DisconnectSource() calls this->Modified(). Therefore
when the imageReader is destroyed the m_Image3D modified time is updated. Is
this an expected behavior? why does the output needs to know that the
process object has been disconnected?

Sorry if this is a naive question,

Julien