[vtkusers] use of vtkInformationKey

[David E DeMarle]

vtkInformation is a map, the keys typed (vtkInformationKey and its
subclasses) the values that are stored in the map are more or less
arbitrary. vtkInformationVectors are arrays of maps.

vtkInformation::Has(),Get(),Set() and Remove() are what you need to
work with them.

vtkDataObjects, vtkAlgorithms and vtkExecutives all have instances of
vtkInformation.  And as David noted, vtkInformation's are usually used
as storage for things that are related to pipeline connectivity and
flow.

David E DeMarle
Kitware, Inc.
R&D Engineer
28 Corporate Drive
Clifton Park, NY 12065-8662
Phone: 518-371-3971 x109



On Fri, Mar 5, 2010 at 8:35 AM, David Doria <daviddoria+vtk at gmail.com> wrote:
> On Fri, Mar 5, 2010 at 7:23 AM, Rakesh Patil <rakeshthp at in.com> wrote:
>>
>> Hello,
>>
>> I was going through the documentation of vtk.. I came across this clas..
>> vtkInformation and vtkInformationKey
>>
>> Can anyone explain me or guide me with an example how to use this class.
>> and when and in what context is this useful..??
>>
>> Thanks
>> Rakesh Patil
>>
>
> I believe these classes are only used to create "the pipeline". You'll
> notice in all the RequestData functions:
> int vtkDelimitedTextReader::RequestData(
>   vtkInformation*,
>   vtkInformationVector**,
>   vtkInformationVector* outputVector)
> I think they just carry around the input/output types and pointers to the
> input/output objects.
> Thanks,
>
> David
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