/* -*- C++ -*-

 *

 * This file is a part of LEMON, a generic C++ optimization library

 *

 * Copyright (C) 2003-2006

 * Egervary Jeno Kombinatorikus Optimalizalasi Kutatocsoport

 * (Egervary Research Group on Combinatorial Optimization, EGRES).

 *

 * Permission to use, modify and distribute this software is granted

 * provided that this copyright notice appears in all copies. For

 * precise terms see the accompanying LICENSE file.

 *

 * This software is provided "AS IS" with no warranty of any kind,

 * express or implied, and with no claim as to its suitability for any

 * purpose.

 *

 */

#ifndef LEMON_BITS_GRAPH_EXTENDER_H

#define LEMON_BITS_GRAPH_EXTENDER_H

#include <lemon/bits/invalid.h>

#include <lemon/error.h>

#include <lemon/bits/map_extender.h>

#include <lemon/bits/default_map.h>

#include <lemon/concept_check.h>

#include <lemon/concept/maps.h>

///\ingroup graphbits

///\file

///\brief Extenders for the graph types

namespace lemon {

  /// \ingroup graphbits

  ///

  /// \brief Extender for the Graphs

  template <typename Base>

  class GraphExtender : public Base {

  public:

    typedef Base Parent;

    typedef GraphExtender Graph;

    // Base extensions

    typedef typename Parent::Node Node;

    typedef typename Parent::Edge Edge;

    int maxId(Node) const {

      return Parent::maxNodeId();

    }

    int maxId(Edge) const {

      return Parent::maxEdgeId();

    }

    Node fromId(int id, Node) const {

      return Parent::nodeFromId(id);

    }

    Edge fromId(int id, Edge) const {

      return Parent::edgeFromId(id);

    }

    Node oppositeNode(const Node &n, const Edge &e) const {

      if (n == Parent::source(e))

	return Parent::target(e);

      else if(n==Parent::target(e))

	return Parent::source(e);

      else

	return INVALID;

    }

    // Alterable extension

    typedef AlterationNotifier<GraphExtender, Node> NodeNotifier;

    typedef AlterationNotifier<GraphExtender, Edge> EdgeNotifier;

  protected:

    mutable NodeNotifier node_notifier;

    mutable EdgeNotifier edge_notifier;

  public:

    NodeNotifier& getNotifier(Node) const {

      return node_notifier;

    }

    EdgeNotifier& getNotifier(Edge) const {

      return edge_notifier;

    }

    class NodeIt : public Node { 

      const Graph* graph;

    public:

      NodeIt() {}

      NodeIt(Invalid i) : Node(i) { }

      explicit NodeIt(const Graph& _graph) : graph(&_graph) {

	_graph.first(static_cast<Node&>(*this));

      }

      NodeIt(const Graph& _graph, const Node& node) 

	: Node(node), graph(&_graph) {}

      NodeIt& operator++() { 

	graph->next(*this);

	return *this; 

      }

    };

    class EdgeIt : public Edge { 

      const Graph* graph;

    public:

      EdgeIt() { }

      EdgeIt(Invalid i) : Edge(i) { }

      explicit EdgeIt(const Graph& _graph) : graph(&_graph) {

	_graph.first(static_cast<Edge&>(*this));

      }

      EdgeIt(const Graph& _graph, const Edge& e) : 

	Edge(e), graph(&_graph) { }

      EdgeIt& operator++() { 

	graph->next(*this);

	return *this; 

      }

    };

    class OutEdgeIt : public Edge { 

      const Graph* graph;

    public:

      OutEdgeIt() { }

      OutEdgeIt(Invalid i) : Edge(i) { }

      OutEdgeIt(const Graph& _graph, const Node& node) 

	: graph(&_graph) {

	_graph.firstOut(*this, node);

      }

      OutEdgeIt(const Graph& _graph, const Edge& edge) 

	: Edge(edge), graph(&_graph) {}

      OutEdgeIt& operator++() { 

	graph->nextOut(*this);

	return *this; 

      }

    };

    class InEdgeIt : public Edge { 

      const Graph* graph;

    public:

      InEdgeIt() { }

      InEdgeIt(Invalid i) : Edge(i) { }

      InEdgeIt(const Graph& _graph, const Node& node) 

	: graph(&_graph) {

	_graph.firstIn(*this, node);

      }

      InEdgeIt(const Graph& _graph, const Edge& edge) : 

	Edge(edge), graph(&_graph) {}

      InEdgeIt& operator++() { 

	graph->nextIn(*this);

	return *this; 

      }

    };

    /// \brief Base node of the iterator

    ///

    /// Returns the base node (i.e. the source in this case) of the iterator

    Node baseNode(const OutEdgeIt &e) const {

      return Parent::source(e);

    }

    /// \brief Running node of the iterator

    ///

    /// Returns the running node (i.e. the target in this case) of the

    /// iterator

    Node runningNode(const OutEdgeIt &e) const {

      return Parent::target(e);

    }

    /// \brief Base node of the iterator

    ///

    /// Returns the base node (i.e. the target in this case) of the iterator

    Node baseNode(const InEdgeIt &e) const {

      return Parent::target(e);

    }

    /// \brief Running node of the iterator

    ///

    /// Returns the running node (i.e. the source in this case) of the

    /// iterator

    Node runningNode(const InEdgeIt &e) const {

      return Parent::source(e);

    }

    template <typename _Value>

    class NodeMap 

      : public MapExtender<DefaultMap<Graph, Node, _Value> > {

    public:

      typedef GraphExtender Graph;

      typedef MapExtender<DefaultMap<Graph, Node, _Value> > Parent;

      explicit NodeMap(const Graph& graph) 

	: Parent(graph) {}

      NodeMap(const Graph& graph, const _Value& value) 

	: Parent(graph, value) {}

      NodeMap& operator=(const NodeMap& cmap) {

	return operator=<NodeMap>(cmap);

      }

      template <typename CMap>

      NodeMap& operator=(const CMap& cmap) {

        Parent::operator=(cmap);

	return *this;

      }

    };

    template <typename _Value>

    class EdgeMap 

      : public MapExtender<DefaultMap<Graph, Edge, _Value> > {

    public:

      typedef GraphExtender Graph;

      typedef MapExtender<DefaultMap<Graph, Edge, _Value> > Parent;

      explicit EdgeMap(const Graph& graph) 

	: Parent(graph) {}

      EdgeMap(const Graph& graph, const _Value& value) 

	: Parent(graph, value) {}

      EdgeMap& operator=(const EdgeMap& cmap) {

	return operator=<EdgeMap>(cmap);

      }

      template <typename CMap>

      EdgeMap& operator=(const CMap& cmap) {

        Parent::operator=(cmap);

	return *this;

      }

    };

    Node addNode() {

      Node node = Parent::addNode();

      getNotifier(Node()).add(node);

      return node;

    }

    Edge addEdge(const Node& from, const Node& to) {

      Edge edge = Parent::addEdge(from, to);

      getNotifier(Edge()).add(edge);

      return edge;

    }

    void clear() {

      getNotifier(Edge()).clear();

      getNotifier(Node()).clear();

      Parent::clear();

    }

    void erase(const Node& node) {

      Edge edge;

      Parent::firstOut(edge, node);

      while (edge != INVALID ) {

	erase(edge);

	Parent::firstOut(edge, node);

      } 

      Parent::firstIn(edge, node);

      while (edge != INVALID ) {

	erase(edge);

	Parent::firstIn(edge, node);

      }

      getNotifier(Node()).erase(node);

      Parent::erase(node);

    }

    void erase(const Edge& edge) {

      getNotifier(Edge()).erase(edge);

      Parent::erase(edge);

    }

    GraphExtender() {

      node_notifier.setContainer(*this);

      edge_notifier.setContainer(*this);

    } 

    ~GraphExtender() {

      edge_notifier.clear();

      node_notifier.clear();

    }

  };

  /// \ingroup graphbits

  ///

  /// \brief Extender for the UGraphs

  template <typename Base> 

  class UGraphExtender : public Base {

  public:

    typedef Base Parent;

    typedef UGraphExtender Graph;

    typedef typename Parent::Node Node;

    typedef typename Parent::Edge Edge;

    typedef typename Parent::UEdge UEdge;

    // UGraph extension    

    int maxId(Node) const {

      return Parent::maxNodeId();

    }

    int maxId(Edge) const {

      return Parent::maxEdgeId();

    }

    int maxId(UEdge) const {

      return Parent::maxUEdgeId();

    }

    Node fromId(int id, Node) const {

      return Parent::nodeFromId(id);

    }

    Edge fromId(int id, Edge) const {

      return Parent::edgeFromId(id);

    }

    UEdge fromId(int id, UEdge) const {

      return Parent::uEdgeFromId(id);

    }

    Node oppositeNode(const Node &n, const UEdge &e) const {

      if( n == Parent::source(e))

	return Parent::target(e);

      else if( n == Parent::target(e))

	return Parent::source(e);

      else

	return INVALID;

    }

    Edge oppositeEdge(const Edge &e) const {

      return Parent::direct(e, !Parent::direction(e));

    }

    using Parent::direct;

    Edge direct(const UEdge &ue, const Node &s) const {

      return Parent::direct(ue, Parent::source(ue) == s);

    }

    // Alterable extension

    typedef AlterationNotifier<UGraphExtender, Node> NodeNotifier;

    typedef AlterationNotifier<UGraphExtender, Edge> EdgeNotifier;

    typedef AlterationNotifier<UGraphExtender, UEdge> UEdgeNotifier;

  protected:

    mutable NodeNotifier node_notifier;

    mutable EdgeNotifier edge_notifier;

    mutable UEdgeNotifier uedge_notifier;

  public:

    NodeNotifier& getNotifier(Node) const {

      return node_notifier;

    }

    EdgeNotifier& getNotifier(Edge) const {

      return edge_notifier;

    }

    UEdgeNotifier& getNotifier(UEdge) const {

      return uedge_notifier;

    }

    class NodeIt : public Node { 

      const Graph* graph;

    public:

      NodeIt() {}

      NodeIt(Invalid i) : Node(i) { }

      explicit NodeIt(const Graph& _graph) : graph(&_graph) {

	_graph.first(static_cast<Node&>(*this));

      }

      NodeIt(const Graph& _graph, const Node& node) 

	: Node(node), graph(&_graph) {}

      NodeIt& operator++() { 

	graph->next(*this);

	return *this; 

      }

    };

    class EdgeIt : public Edge { 

      const Graph* graph;

    public:

      EdgeIt() { }

      EdgeIt(Invalid i) : Edge(i) { }

      explicit EdgeIt(const Graph& _graph) : graph(&_graph) {

	_graph.first(static_cast<Edge&>(*this));

      }

      EdgeIt(const Graph& _graph, const Edge& e) : 

	Edge(e), graph(&_graph) { }

      EdgeIt& operator++() { 

	graph->next(*this);

	return *this; 

      }

    };

    class OutEdgeIt : public Edge { 

      const Graph* graph;

    public:

      OutEdgeIt() { }

      OutEdgeIt(Invalid i) : Edge(i) { }

      OutEdgeIt(const Graph& _graph, const Node& node) 

	: graph(&_graph) {

	_graph.firstOut(*this, node);

      }

      OutEdgeIt(const Graph& _graph, const Edge& edge) 

	: Edge(edge), graph(&_graph) {}

      OutEdgeIt& operator++() { 

	graph->nextOut(*this);

	return *this; 

      }

    };

    class InEdgeIt : public Edge { 

      const Graph* graph;

    public:

      InEdgeIt() { }

      InEdgeIt(Invalid i) : Edge(i) { }

      InEdgeIt(const Graph& _graph, const Node& node) 

	: graph(&_graph) {

	_graph.firstIn(*this, node);

      }

      InEdgeIt(const Graph& _graph, const Edge& edge) : 

	Edge(edge), graph(&_graph) {}

      InEdgeIt& operator++() { 

	graph->nextIn(*this);

	return *this; 

      }

    };

    class UEdgeIt : public Parent::UEdge { 

      const Graph* graph;

    public:

      UEdgeIt() { }

      UEdgeIt(Invalid i) : UEdge(i) { }

      explicit UEdgeIt(const Graph& _graph) : graph(&_graph) {

	_graph.first(static_cast<UEdge&>(*this));

      }

      UEdgeIt(const Graph& _graph, const UEdge& e) : 

	UEdge(e), graph(&_graph) { }

      UEdgeIt& operator++() { 

	graph->next(*this);

	return *this; 

      }

    };

    class IncEdgeIt : public Parent::UEdge {

      friend class UGraphExtender;

      const Graph* graph;

      bool direction;

    public:

      IncEdgeIt() { }

      IncEdgeIt(Invalid i) : UEdge(i), direction(false) { }

      IncEdgeIt(const Graph& _graph, const Node &n) : graph(&_graph) {

	_graph.firstInc(*this, direction, n);

      }

      IncEdgeIt(const Graph& _graph, const UEdge &ue, const Node &n)

	: graph(&_graph), UEdge(ue) {

	direction = (_graph.source(ue) == n);

      }

      IncEdgeIt& operator++() {

	graph->nextInc(*this, direction);

	return *this; 

      }

    };

    /// \brief Base node of the iterator

    ///

    /// Returns the base node (ie. the source in this case) of the iterator

    Node baseNode(const OutEdgeIt &e) const {

      return Parent::source((Edge)e);

    }

    /// \brief Running node of the iterator

    ///

    /// Returns the running node (ie. the target in this case) of the

    /// iterator

    Node runningNode(const OutEdgeIt &e) const {

      return Parent::target((Edge)e);

    }

    /// \brief Base node of the iterator

    ///

    /// Returns the base node (ie. the target in this case) of the iterator

    Node baseNode(const InEdgeIt &e) const {

      return Parent::target((Edge)e);

    }

    /// \brief Running node of the iterator

    ///

    /// Returns the running node (ie. the source in this case) of the

    /// iterator

    Node runningNode(const InEdgeIt &e) const {

      return Parent::source((Edge)e);

    }

    /// Base node of the iterator

    ///

    /// Returns the base node of the iterator

    Node baseNode(const IncEdgeIt &e) const {

      return e.direction ? source(e) : target(e);

    }

    /// Running node of the iterator

    ///

    /// Returns the running node of the iterator

    Node runningNode(const IncEdgeIt &e) const {

      return e.direction ? target(e) : source(e);

    }

    // Mappable extension

    template <typename _Value>

    class NodeMap 

      : public MapExtender<DefaultMap<Graph, Node, _Value> > {

    public:

      typedef UGraphExtender Graph;

      typedef MapExtender<DefaultMap<Graph, Node, _Value> > Parent;

      NodeMap(const Graph& graph) 

	: Parent(graph) {}

      NodeMap(const Graph& graph, const _Value& value) 

	: Parent(graph, value) {}

      NodeMap& operator=(const NodeMap& cmap) {

	return operator=<NodeMap>(cmap);

      }

      template <typename CMap>

      NodeMap& operator=(const CMap& cmap) {

        Parent::operator=(cmap);

	return *this;

      }

    };

    template <typename _Value>

    class EdgeMap 

      : public MapExtender<DefaultMap<Graph, Edge, _Value> > {

    public:

      typedef UGraphExtender Graph;

      typedef MapExtender<DefaultMap<Graph, Edge, _Value> > Parent;

      EdgeMap(const Graph& graph) 

	: Parent(graph) {}

      EdgeMap(const Graph& graph, const _Value& value) 

	: Parent(graph, value) {}

      EdgeMap& operator=(const EdgeMap& cmap) {

	return operator=<EdgeMap>(cmap);

      }

      template <typename CMap>

      EdgeMap& operator=(const CMap& cmap) {

        Parent::operator=(cmap);

	return *this;

      }

    };

    template <typename _Value>

    class UEdgeMap 

      : public MapExtender<DefaultMap<Graph, UEdge, _Value> > {

    public:

      typedef UGraphExtender Graph;

      typedef MapExtender<DefaultMap<Graph, UEdge, _Value> > Parent;

      UEdgeMap(const Graph& graph) 

	: Parent(graph) {}

      UEdgeMap(const Graph& graph, const _Value& value) 

	: Parent(graph, value) {}

      UEdgeMap& operator=(const UEdgeMap& cmap) {

	return operator=<UEdgeMap>(cmap);

      }

      template <typename CMap>

      UEdgeMap& operator=(const CMap& cmap) {

        Parent::operator=(cmap);

	return *this;

      }

    };

    // Alteration extension

    Node addNode() {

      Node node = Parent::addNode();

      getNotifier(Node()).add(node);

      return node;

    }

    UEdge addEdge(const Node& from, const Node& to) {

      UEdge uedge = Parent::addEdge(from, to);

      getNotifier(UEdge()).add(uedge);

      getNotifier(Edge()).add(Parent::direct(uedge, true));

      getNotifier(Edge()).add(Parent::direct(uedge, false));

      return uedge;

    }

    void clear() {

      getNotifier(Edge()).clear();

      getNotifier(UEdge()).clear();

      getNotifier(Node()).clear();

      Parent::clear();

    }

    void erase(const Node& node) {

      Edge edge;

      Parent::firstOut(edge, node);

      while (edge != INVALID ) {

	erase(edge);

	Parent::firstOut(edge, node);

      } 

      Parent::firstIn(edge, node);

      while (edge != INVALID ) {

	erase(edge);

	Parent::firstIn(edge, node);

      }

      getNotifier(Node()).erase(node);

      Parent::erase(node);

    }

    void erase(const UEdge& uedge) {

      getNotifier(Edge()).erase(Parent::direct(uedge, true));

      getNotifier(Edge()).erase(Parent::direct(uedge, false));

      getNotifier(UEdge()).erase(uedge);

      Parent::erase(uedge);

    }

    UGraphExtender() {

      node_notifier.setContainer(*this); 

      edge_notifier.setContainer(*this);

      uedge_notifier.setContainer(*this);

    } 

    ~UGraphExtender() {

      uedge_notifier.clear();

      edge_notifier.clear();

      node_notifier.clear(); 

    } 

  };

  /// \ingroup graphbits

  ///

  /// \brief Extender for the BpUGraphs

  template <typename Base>

  class BpUGraphExtender : public Base {

  public:

    typedef Base Parent;

    typedef BpUGraphExtender Graph;

    typedef typename Parent::Node Node;

    typedef typename Parent::UEdge UEdge;

    using Parent::first;

    using Parent::next;

    using Parent::id;

    class ANode : public Node {

      friend class BpUGraphExtender;

    public:

      ANode() {}

      ANode(const Node& node) : Node(node) {

	LEMON_ASSERT(Parent::aNode(node) || node == INVALID, 

		     typename Parent::NodeSetError());

      }

      ANode(Invalid) : Node(INVALID) {}

    };

    void first(ANode& node) const {

      Parent::firstANode(static_cast<Node&>(node));

    }

    void next(ANode& node) const {

      Parent::nextANode(static_cast<Node&>(node));

    }

    int id(const ANode& node) const {

      return Parent::aNodeId(node);

    }

    class BNode : public Node {

      friend class BpUGraphExtender;

    public:

      BNode() {}

      BNode(const Node& node) : Node(node) {

	LEMON_ASSERT(Parent::bNode(node) || node == INVALID,

		     typename Parent::NodeSetError());

      }

      BNode(Invalid) : Node(INVALID) {}

    };

    void first(BNode& node) const {

      Parent::firstBNode(static_cast<Node&>(node));

    }

    void next(BNode& node) const {

      Parent::nextBNode(static_cast<Node&>(node));

    }

    int id(const BNode& node) const {

      return Parent::aNodeId(node);

    }

    Node source(const UEdge& edge) const {

      return aNode(edge);

    }

    Node target(const UEdge& edge) const {

      return bNode(edge);

    }

    void firstInc(UEdge& edge, bool& direction, const Node& node) const {

      if (Parent::aNode(node)) {

	Parent::firstFromANode(edge, node);

	direction = true;

      } else {

	Parent::firstFromBNode(edge, node);

	direction = static_cast<UEdge&>(edge) == INVALID;

      }

    }

    void nextInc(UEdge& edge, bool& direction) const {

      if (direction) {

	Parent::nextFromANode(edge);

      } else {

	Parent::nextFromBNode(edge);

	if (edge == INVALID) direction = true;

      }

    }

    class Edge : public UEdge {

      friend class BpUGraphExtender;

    protected:

      bool forward;

      Edge(const UEdge& edge, bool _forward)

	: UEdge(edge), forward(_forward) {}

    public:

      Edge() {}

      Edge (Invalid) : UEdge(INVALID), forward(true) {}

      bool operator==(const Edge& i) const {

	return UEdge::operator==(i) && forward == i.forward;

      }

      bool operator!=(const Edge& i) const {

	return UEdge::operator!=(i) || forward != i.forward;

      }

      bool operator<(const Edge& i) const {

	return UEdge::operator<(i) || 

	  (!(i.forward<forward) && UEdge(*this)<UEdge(i));

      }

    };

    void first(Edge& edge) const {

      Parent::first(static_cast<UEdge&>(edge));

      edge.forward = true;

    }

    void next(Edge& edge) const {

      if (!edge.forward) {

	Parent::next(static_cast<UEdge&>(edge));

      }

      edge.forward = !edge.forward;

    }

    void firstOut(Edge& edge, const Node& node) const {

      if (Parent::aNode(node)) {

	Parent::firstFromANode(edge, node);

	edge.forward = true;

      } else {

	Parent::firstFromBNode(edge, node);

	edge.forward = static_cast<UEdge&>(edge) == INVALID;

      }

    }

    void nextOut(Edge& edge) const {

      if (edge.forward) {

	Parent::nextFromANode(edge);

      } else {

	Parent::nextFromBNode(edge);

        edge.forward = static_cast<UEdge&>(edge) == INVALID;

      }

    }

    void firstIn(Edge& edge, const Node& node) const {

      if (Parent::bNode(node)) {

	Parent::firstFromBNode(edge, node);

	edge.forward = true;	

      } else {

	Parent::firstFromANode(edge, node);

	edge.forward = static_cast<UEdge&>(edge) == INVALID;

      }

    }

    void nextIn(Edge& edge) const {

      if (edge.forward) {

	Parent::nextFromBNode(edge);

      } else {

	Parent::nextFromANode(edge);

	edge.forward = static_cast<UEdge&>(edge) == INVALID;

      }

    }

    Node source(const Edge& edge) const {

      return edge.forward ? Parent::aNode(edge) : Parent::bNode(edge);

    }

    Node target(const Edge& edge) const {

      return edge.forward ? Parent::bNode(edge) : Parent::aNode(edge);

    }

    int id(const Edge& edge) const {

      return (Parent::id(static_cast<const UEdge&>(edge)) << 1) + 

        (edge.forward ? 0 : 1);

    }

    Edge edgeFromId(int id) const {

      return Edge(Parent::fromUEdgeId(id >> 1), (id & 1) == 0);

    }

    int maxEdgeId() const {

      return (Parent::maxUEdgeId(UEdge()) << 1) + 1;

    }

    bool direction(const Edge& edge) const {

      return edge.forward;

    }

    Edge direct(const UEdge& edge, bool direction) const {

      return Edge(edge, direction);

    }

    int edgeNum() const {

      return 2 * Parent::uEdgeNum();

    }

    int uEdgeNum() const {

      return Parent::uEdgeNum();

    }

    Node oppositeNode(const UEdge& edge, const Node& node) const {

      return source(edge) == node ? 

	target(edge) : source(edge);

    }

    Edge direct(const UEdge& edge, const Node& node) const {

      return Edge(edge, node == Parent::source(edge));

    }

    Edge oppositeEdge(const Edge& edge) const {

      return Parent::direct(edge, !Parent::direction(edge));

    }

    int maxId(Node) const {

      return Parent::maxNodeId();

    }

    int maxId(BNode) const {

      return Parent::maxBNodeId();

    }

    int maxId(ANode) const {

      return Parent::maxANodeId();

    }

    int maxId(Edge) const {

      return maxEdgeId();

    }

    int maxId(UEdge) const {

      return Parent::maxUEdgeId();

    }

    Node fromId(int id, Node) const {

      return Parent::nodeFromId(id);

    }

    ANode fromId(int id, ANode) const {

      return Parent::fromANodeId(id);

    }

    BNode fromId(int id, BNode) const {

      return Parent::fromBNodeId(id);

    }

    Edge fromId(int id, Edge) const {

      return Parent::edgeFromId(id);

    }

    UEdge fromId(int id, UEdge) const {

      return Parent::uEdgeFromId(id);

    }  

    typedef AlterationNotifier<BpUGraphExtender, ANode> ANodeNotifier;

    typedef AlterationNotifier<BpUGraphExtender, BNode> BNodeNotifier;

    typedef AlterationNotifier<BpUGraphExtender, Node> NodeNotifier;

    typedef AlterationNotifier<BpUGraphExtender, Edge> EdgeNotifier;

    typedef AlterationNotifier<BpUGraphExtender, UEdge> UEdgeNotifier;

  protected:

    mutable ANodeNotifier anode_notifier;

    mutable BNodeNotifier bnode_notifier;

    mutable NodeNotifier node_notifier;

    mutable EdgeNotifier edge_notifier;

    mutable UEdgeNotifier uedge_notifier;

  public:

    NodeNotifier& getNotifier(Node) const {

      return node_notifier;

    }

    ANodeNotifier& getNotifier(ANode) const {

      return anode_notifier;

    }

    BNodeNotifier& getNotifier(BNode) const {

      return bnode_notifier;

    }