/*=========================================================================

  Program:   Visualization Toolkit
  Module:    $RCSfile: vtkTree.h,v $

  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.
-------------------------------------------------------------------------*/
// .NAME vtkTree - A rooted tree data structure.
//
// .SECTION Description
// vtkTree is a connected directed graph with no cycles. A tree is a type of
// directed graph, so works with all graph algorithms.
//
// vtkTree is a read-only data structure.
// To construct a tree, create an instance of vtkMutableDirectedGraph.
// Add vertices and edges with AddVertex() and AddEdge(). You may alternately
// start by adding a single vertex as the root then call graph->AddChild(parent)
// which adds a new vertex and connects the parent to the child.
// The tree MUST have all edges in the proper direction, from parent to child.
// After building the tree, call tree->CheckedShallowCopy(graph) to copy the
// structure into a vtkTree. This method will return false if the graph is
// an invalid tree.
//
// vtkTree provides some convenience methods for obtaining the parent and
// children of a vertex, for finding the root, and determining if a vertex
// is a leaf (a vertex with no children).
//
// .SECTION See Also
// vtkDirectedGraph vtkMutableDirectedGraph vtkGraph

#ifndef __vtkTree_h
#define __vtkTree_h

#include "vtkDirectedAcyclicGraph.h"

class vtkIdTypeArray;

class VTK_FILTERING_EXPORT vtkTree : public vtkDirectedAcyclicGraph
{
public:
  static vtkTree *New();
  vtkTypeRevisionMacro(vtkTree, vtkDirectedAcyclicGraph);
  void PrintSelf(ostream& os, vtkIndent indent);

  // Description:
  // Return what type of dataset this is.
  virtual int GetDataObjectType() {return VTK_TREE;}

  // Description:
  // Get the root vertex of the tree.
  vtkGetMacro(Root, vtkIdType);

  // Description:
  // Get the number of children of a vertex.
  vtkIdType GetNumberOfChildren(vtkIdType v)
    { return this->GetOutDegree(v); }

  // Description:
  // Get the i-th child of a parent vertex.
  vtkIdType GetChild(vtkIdType v, vtkIdType i);

  // Description:
  // Get the child vertices of a vertex.
  // This is a convenience method that functions exactly like
  // GetAdjacentVertices.
  void GetChildren(vtkIdType v, vtkAdjacentVertexIterator *it)
    { this->GetAdjacentVertices(v, it); }

  // Description:
  // Get the parent of a vertex.
  vtkIdType GetParent(vtkIdType v);

  // Description:
  // Get the edge connecting the vertex to its parent.
  vtkEdgeType GetParentEdge(vtkIdType v);

  // Description:
  // Get the level of the vertex in the tree.  The root vertex has level 0.
  // Returns -1 if the vertex id is < 0 or greater than the number of vertices
  // in the tree.
  vtkIdType GetLevel(vtkIdType v);
  
  // Description:
  // Return whether the vertex is a leaf (i.e. it has no children).
  bool IsLeaf(vtkIdType vertex);

  //BTX
  // Description:
  // Retrieve a graph from an information vector.
  static vtkTree *GetData(vtkInformation *info);
  static vtkTree *GetData(vtkInformationVector *v, int i=0);
  //ETX

  // Description:
  // Reorder the children of a parent vertex.
  // The children array must contain all the children of parent,
  // just in a different order.
  // This does not change the topology of the tree.
  virtual void ReorderChildren(vtkIdType parent, vtkIdTypeArray *children);

protected:
  vtkTree();
  ~vtkTree();

  // Description:
  // Check the storage, and accept it if it is a valid
  // tree.
  virtual bool IsStructureValid(vtkGraph *g);

  // Description:
  // The root of the tree.
  vtkIdType Root;

private:
  vtkTree(const vtkTree&);  // Not implemented.
  void operator=(const vtkTree&);  // Not implemented.
};

#endif
