[vtkusers] Accessing keys in vtkInformation without having key pointers at first

[Berk Geveci]

You need to use the vtkInformationIterator class.

Best,
-berk


On Wed, Apr 24, 2013 at 4:29 PM, Sunrise <helios.corona at gmail.com> wrote:

> Sorry if the question that I asked was not clear. I would like to ask a
> similar question:
>
> Given a vtkInformation object, how can we know what key-value pairs are
> appended into it?
>
> Thanks.
>
> On 04/21/2013 08:09 PM, Sunrise wrote:
> > I would like to find /search for keys appended in vtkInformation object
> > and then access their values. But, it seems that if we do not have key
> > pointers, we can not inquiry the vtkInformaton that which key-pairs it
> > contains!
> >
> > Assume I have vtkInformation *inputInfo object in Filter2, that coming
> > from previous filter (Filter1) in a pipeline. Filter1 added some
> > key/value pairs of type vtkInformationDoubleVectorkey into outputInfo
> > object. Now, in the new filter (Filter2) I want to access DoubleVector
> key.
> >
> > In Filter1 header, a key is defined with a static function:
> > static vtkInformationDoubleVectorKey * MyKey();
> >
> > key-value pair is appended to outputInfo with:
> > outputInfo->Set(Filter1::MyKey(),someValues,someLength);
> >
> > So in Filter2 by calling Filter1::MyKey(), I can access the key values
> via:
> > values = inputInfo->Get(Filter1::MyKey());
> >
> > But, the problem is that Filter1 could be one of more general filters
> > that create their own key. Filter2 is not restricted to be connected
> > just to Filter1, downstream of Filter2 can be FilterX. So I do not know
> > which FilterX generated key for DoubleVector type in inputInfo. "All the
> > Filter2 should know is that in inputInfo there is a key-value pair with
> > DoubleVector type".
> >
> > Also I don't want to create a superclass for my filters and generate
> > keys at there (something that vtkStreamingDemandDrivenPipeline does for
> > its keys).
> >
> > I looked at this thread
> >
> >
> http://vtk.1045678.n5.nabble.com/vtkInformation-access-with-equivalent-keys-td5545920.html
> >
> > to figure out how can I access keys with other similar key-types. The
> > answer suggests to use CopyEntries method. If you look at source code
> > for vtkInformation::CopyEntries(...), you will see that keys in info
> > should be know again in order to use CopyEntries.
> >
> > Any idea would be appreciated.
>
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