text: /*=========================================================================
  
    Program:   Visualization Toolkit
    Module:    vtkDirectedGraphAlgorithm.cxx
  
    Copyright (c) Ken Martin, Will Schroeder, Bill Lorensen
    All rights reserved.
    See Copyright.txt or http://www.kitware.com/Copyright.htm for details.
  
       This software is distributed WITHOUT ANY WARRANTY; without even
       the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR
       PURPOSE.  See the above copyright notice for more information.
  
  =========================================================================*/
  /*-------------------------------------------------------------------------
    Copyright 2008 Sandia Corporation.
    Under the terms of Contract DE-AC04-94AL85000 with Sandia Corporation,
    the U.S. Government retains certain rights in this software.
  -------------------------------------------------------------------------*/
  #include "vtkDirectedGraphAlgorithm.h"
  
  #include "vtkCommand.h"
  #include "vtkInformation.h"
  #include "vtkInformationVector.h"
  #include "vtkObjectFactory.h"
  #include "vtkDirectedGraph.h"
  #include "vtkStreamingDemandDrivenPipeline.h"
  
  vtkStandardNewMacro(vtkDirectedGraphAlgorithm);
  
  //----------------------------------------------------------------------------
  vtkDirectedGraphAlgorithm::vtkDirectedGraphAlgorithm()
  {
    // by default assume filters have one input and one output
    // subclasses that deviate should modify this setting
    this->SetNumberOfInputPorts(1);
    this->SetNumberOfOutputPorts(1);
  }
  
  //----------------------------------------------------------------------------
  vtkDirectedGraphAlgorithm::~vtkDirectedGraphAlgorithm()
  {
  }
  
  //----------------------------------------------------------------------------
  void vtkDirectedGraphAlgorithm::PrintSelf(ostream& os, vtkIndent indent)
  {
    this->Superclass::PrintSelf(os, indent);
  }
  
  //----------------------------------------------------------------------------
  int vtkDirectedGraphAlgorithm::ProcessRequest(vtkInformation* request,
                                           vtkInformationVector** inputVector,
                                           vtkInformationVector* outputVector)
  {
    // generate the data
    if(request->Has(vtkDemandDrivenPipeline::REQUEST_DATA()))
      {
      return this->RequestData(request, inputVector, outputVector);
      }
  
    if(request->Has(vtkStreamingDemandDrivenPipeline::REQUEST_UPDATE_EXTENT()))
      {
      return this->RequestUpdateExtent(request, inputVector, outputVector);
      }
  
    // execute information
    if(request->Has(vtkDemandDrivenPipeline::REQUEST_INFORMATION()))
      {
      return this->RequestInformation(request, inputVector, outputVector);
      }
  
    return this->Superclass::ProcessRequest(request, inputVector, outputVector);
  }
  
  //----------------------------------------------------------------------------
  int vtkDirectedGraphAlgorithm::FillOutputPortInformation(
    int vtkNotUsed(port), vtkInformation* info)
  {
    // now add our info
    info->Set(vtkDataObject::DATA_TYPE_NAME(), "vtkDirectedGraph");
    return 1;
  }
  
  //----------------------------------------------------------------------------
  int vtkDirectedGraphAlgorithm::FillInputPortInformation(
    int vtkNotUsed(port), vtkInformation* info)
  {
    info->Set(vtkAlgorithm::INPUT_REQUIRED_DATA_TYPE(), "vtkDirectedGraph");
    return 1;
  }
  
  //----------------------------------------------------------------------------
  vtkDirectedGraph* vtkDirectedGraphAlgorithm::GetOutput(int index)
  {
    return vtkDirectedGraph::SafeDownCast(this->GetOutputDataObject(index));
  }
  
  //----------------------------------------------------------------------------
  void vtkDirectedGraphAlgorithm::SetInputData(int index, vtkDataObject* input)
  {
    this->SetInputDataInternal(index, input);
  }
  
  //----------------------------------------------------------------------------
  int vtkDirectedGraphAlgorithm::RequestInformation(
    vtkInformation* vtkNotUsed(request),
    vtkInformationVector** vtkNotUsed(inputVector),
    vtkInformationVector* vtkNotUsed(outputVector))
  {
    // do nothing let subclasses handle it
    return 1;
  }
  
  //----------------------------------------------------------------------------
  int vtkDirectedGraphAlgorithm::RequestUpdateExtent(
    vtkInformation* vtkNotUsed(request),
    vtkInformationVector** inputVector,
    vtkInformationVector* vtkNotUsed(outputVector))
  {
    int numInputPorts = this->GetNumberOfInputPorts();
    for (int i=0; i<numInputPorts; i++)
      {
      int numInputConnections = this->GetNumberOfInputConnections(i);
      for (int j=0; j<numInputConnections; j++)
        {
        vtkInformation* inputInfo = inputVector[i]->GetInformationObject(j);
        inputInfo->Set(vtkStreamingDemandDrivenPipeline::EXACT_EXTENT(), 1);
        }
      }
    return 1;
  }
  
  //----------------------------------------------------------------------------
  // This is the superclasses style of Execute method.  Convert it into
  // an imaging style Execute method.
  int vtkDirectedGraphAlgorithm::RequestData(
    vtkInformation* vtkNotUsed( request ),
    vtkInformationVector** vtkNotUsed( inputVector ),
    vtkInformationVector* vtkNotUsed( outputVector ) )
  {
    return 0;
  }
  
  