#ifndef MAP_REGISTRY_H

 #define MAP_REGISTRY_H

 #include <vector>

 using namespace std;

 namespace lemon {

 /** 

  * Registry class to register edge or node maps into the graph. The

  * registry helps you to implement an observer pattern. If you add

  * or erase an edge or node you must notify all the maps about the

  * event.

 */

   template <typename G, typename K, typename KIt>

   class MapRegistry {

   public:

     typedef G Graph;

     typedef K Key;

     typedef KIt KeyIt;

     /**

      * MapBase is the base class of the registered maps.

      * It defines the core modification operations on the maps and

      * implements some helper functions. 

      */

     class MapBase {

     public:

       typedef G Graph;

       typedef MapRegistry<G, K, KIt> Registry;

       typedef K Key;

       typedef KIt KeyIt;

       friend class Registry;

       /**

        * Default constructor for MapBase.

        */

       MapBase() : graph(0), registry(0) {}

       /** 

        * Simple constructor to register into a graph registry.

       */

       MapBase(const Graph& g, Registry& r) : graph(&g), registry(0) {

 	r.attach(*this);

       }

       /** 

        * Copy constructor to register into the registry.

       */	

       MapBase(const MapBase& copy) : registry(0), graph(copy.graph) {

 	if (copy.registry) {

 	  copy.registry->attach(*this);

 	}

       } 

       /** 

        * Assign operator.

       */	

       const MapBase& operator=(const MapBase& copy) {

 	if (registry) {

 	  registry->detach(*this);

 	}

 	graph = copy.graph;

 	if (copy.registry) {

 	  copy.registry->attach(*this);

 	}

       }

       /** 

        * Destructor. 

       */		

       virtual ~MapBase() {

 	if (registry) {

 	  registry->detach(*this);

 	}

       }

       /*

        * Returns the graph that the map belongs to.

       */

       const Graph* getGraph() const { return graph; }

     protected:

       const Graph* graph;     

       Registry* registry;

       int registry_index;

     protected:

       /**

 	 Helper function to implement constructors in the subclasses.

       */

       virtual void init() {

 	for (KeyIt it(*graph); graph->valid(it); graph->next(it)) {

 	  add(it);

 	}

       }

       /**

 	 Helper function to implement the destructor in the subclasses.

       */

       virtual void destroy() {

 	for (KeyIt it(*getGraph()); getGraph()->valid(it); getGraph()->next(it)) {

 	  erase(it);

 	}

       }

       /** 

 	  The add member function should be overloaded in the subclasses.

 	  \e Add extends the map with the new node.

       */

       virtual void add(const Key&) = 0;	

       /** 

 	  The erase member function should be overloaded in the subclasses.

 	  \e Erase removes the node from the map.

       */

       virtual void erase(const Key&) = 0;

       /**

 	 Exception class to throw at unsupported operation.

       */

       class NotSupportedOperationException {};

     };

   protected:

     /** 

      * The container type of the maps.

      */

     typedef std::vector<MapBase*> Container; 

     /**

      * The container of the registered maps.

      */

     Container container;

   public:

     /**

      * Default Constructor of the MapRegistry. It creates an empty registry.

      */

     MapRegistry() {}

     /**

      * Copy Constructor of the MapRegistry. The new registry does not steal

      * the maps from the right value. The new registry will be an empty.

      */

     MapRegistry(const MapRegistry&) {}

     /**

      * Assign operator. The left value does not steal the maps 

      * from the right value. The left value will be an empty registry.

      */

     MapRegistry& operator=(const MapRegistry&) {

       for (it = container.begin(); it != container.end(); ++it) {

 	(*it)->destroy();

 	(*it)->graph = 0;

 	(*it)->registry = 0;

       }

     }

     /**

      * Destructor of the MapRegistry.

      */

     ~MapRegistry() {

       typename Container::iterator it;

       for (it = container.begin(); it != container.end(); ++it) {

 	(*it)->destroy();

 	(*it)->registry = 0;

 	(*it)->graph = 0;

       }

     }

     public:

     /**

      * Attach a map into thr registry. If the map has been attached

      * into an other registry it is detached from that automaticly.

      */

     void attach(MapBase& map) {

       if (map.registry) {

 	map.registry->detach(map);

       }

       container.push_back(&map);

       map.registry = this;

       map.registry_index = container.size()-1;

     } 

     /**

      * Detach the map from the registry.

      */

     void detach(MapBase& map) {

       container.back()->registry_index = map.registry_index; 

       container[map.registry_index] = container.back();

       container.pop_back();

       map.registry = 0;

       map.graph = 0;

     }

     /**

      * Notify all the registered maps about a Key added.

      */

     virtual void add(Key& key) {

       typename Container::iterator it;

       for (it = container.begin(); it != container.end(); ++it) {

 	(*it)->add(key);

       }

     }	

     /**

      * Notify all the registered maps about a Key erased.

      */ 

     virtual void erase(Key& key) {

       typename Container::iterator it;

       for (it = container.begin(); it != container.end(); ++it) {

 	(*it)->erase(key);

       }

     }

   };

 }

 #endif