[vtk-developers] When should this->NumberOfOutputs be set?

[Peter J. Bismuti]

When writing a data reader such as vtkPLOT3DReader, when should 
this->NumberOfOutputs be set?  In ExecuteInformation()?  It seems this value 
is already set before the Execute() method is called.   

This reader also has a method:

int vtkPLOT3DReader::GetNumberOfOutputsInternal(FILE* xyzFp, int verify)

What is the strategy behind this?  Is it necessary?  

Thanks in advance