klao@946: /* -*- C++ -*-
klao@946:  *
alpar@1956:  * This file is a part of LEMON, a generic C++ optimization library
alpar@1956:  *
alpar@1956:  * Copyright (C) 2003-2006
alpar@1956:  * Egervary Jeno Kombinatorikus Optimalizalasi Kutatocsoport
alpar@1956:  * (Egervary Research Group on Combinatorial Optimization, EGRES).
klao@946:  *
klao@946:  * Permission to use, modify and distribute this software is granted
klao@946:  * provided that this copyright notice appears in all copies. For
klao@946:  * precise terms see the accompanying LICENSE file.
klao@946:  *
klao@946:  * This software is provided "AS IS" with no warranty of any kind,
klao@946:  * express or implied, and with no claim as to its suitability for any
klao@946:  * purpose.
klao@946:  *
klao@946:  */
klao@946: 
deba@1989: #ifndef LEMON_ALTERATION_NOTIFIER_H
deba@1989: #define LEMON_ALTERATION_NOTIFIER_H
klao@946: 
klao@946: #include <vector>
klao@946: #include <algorithm>
klao@946: 
alpar@1946: ///\ingroup graphmapfactory
klao@946: ///\file
klao@946: ///\brief Observer registry for graph alteration observers.
klao@946: 
klao@946: namespace lemon {
klao@946: 
deba@1989:   /// \addtogroup graphmapfactory
klao@946:   /// @{
klao@946: 
deba@1414:   /// \brief Registry class to register objects observes alterations in 
deba@1414:   /// the graph.
deba@1414:   ///
klao@946:   /// This class is a registry for the objects which observe the
klao@946:   /// alterations in a container. The alteration observers can be attached
klao@946:   /// to and detached from the registry. The observers have to inherit
deba@1038:   /// from the \ref AlterationNotifier::ObserverBase and override
klao@946:   /// the virtual functions in that.
klao@946:   ///
klao@946:   /// The most important application of the alteration observing is the
deba@1414:   /// dynamic map implementation.
klao@946:   ///
klao@946:   /// \param _Item The item type what the observers are observing, usually
klao@946:   /// edge or node.
klao@946:   ///
klao@946:   /// \author Balazs Dezso
klao@946: 
klao@946:   template <typename _Item>
deba@1038:   class AlterationNotifier {
klao@946:   public:
deba@1989: 
deba@1989:     typedef True Notifier;
deba@1989: 
klao@946:     typedef _Item Item;
klao@946: 
klao@946:     /// ObserverBase is the base class for the observers.
klao@946: 	
klao@946:     /// ObserverBase is the abstract base class for the observers.
klao@946:     /// It will be notified about an item was inserted into or
klao@946:     /// erased from the graph.
klao@946:     ///
klao@946:     /// The observer interface contains some pure virtual functions
klao@946:     /// to override. The add() and erase() functions are
klao@946:     /// to notify the oberver when one item is added or
klao@946:     /// erased.
klao@946:     ///
klao@946:     /// The build() and clear() members are to notify the observer
alpar@1204:     /// about the container is built from an empty container or
klao@946:     /// is cleared to an empty container. 
klao@946:     /// 
klao@946:     /// \author Balazs Dezso
klao@946: 
klao@946:     class ObserverBase {
klao@946:     protected:
deba@1038:       typedef AlterationNotifier Registry;
klao@946: 
deba@1038:       friend class AlterationNotifier;
klao@946: 
deba@1414:       /// \brief Default constructor.
deba@1414:       ///
klao@946:       /// Default constructor for ObserverBase.
klao@946:       /// 
klao@946:       ObserverBase() : registry(0) {}
klao@946: 
deba@1685:       ObserverBase(const ObserverBase& copy) {
deba@1685: 	if (copy.attached()) {
deba@1685: 	  copy.getRegistry()->attach(*this);
deba@1685: 	}
deba@1685:       }
deba@1685: 	
klao@946:       virtual ~ObserverBase() {}
klao@946: 
deba@1414:       /// \brief Attaches the observer into an AlterationNotifier.
deba@1414:       ///
deba@1038:       /// This member attaches the observer into an AlterationNotifier.
klao@946:       ///
deba@1038:       void attach(AlterationNotifier& r) {
klao@946: 	registry = &r;
klao@946: 	registry->attach(*this);
klao@946:       }
klao@946: 
deba@1414:       /// \brief Detaches the observer into an AlterationNotifier.
deba@1414:       ///
deba@1038:       /// This member detaches the observer from an AlterationNotifier.
klao@946:       ///
klao@946:       void detach() {
klao@946: 	if (registry) {
klao@946: 	  registry->detach(*this);
klao@946: 	}
klao@946:       }
klao@946: 	
klao@946: 
klao@946:       /// Gives back a pointer to the registry what the map attached into.
klao@946: 
klao@946:       /// This function gives back a pointer to the registry what the map
klao@946:       /// attached into.
klao@946:       ///
klao@946:       Registry* getRegistry() const { return const_cast<Registry*>(registry); }
klao@946:       
klao@946:       /// Gives back true when the observer is attached into a registry.
klao@946:       bool attached() const { return registry != 0; }
deba@1685: 
klao@946:     private:
klao@946: 
klao@946:       ObserverBase& operator=(const ObserverBase& copy);
klao@946: 
klao@946:     protected:
klao@946:       
klao@946:       Registry* registry;
klao@946:       int registry_index;
klao@946: 
klao@946:       /// \brief The member function to notificate the observer about an
klao@946:       /// item is added to the container.
klao@946:       ///
klao@946:       /// The add() member function notificates the observer about an item
klao@946:       /// is added to the container. It have to be overrided in the
klao@946:       /// subclasses.
klao@946: 	
deba@1414:       virtual void add(const Item&) = 0;
klao@946: 
deba@1414:       /// \brief The member function to notificate the observer about 
deba@1718:       /// more item is added to the container.
deba@1414:       ///
deba@1718:       /// The add() member function notificates the observer about more item
deba@1414:       /// is added to the container. It have to be overrided in the
deba@1414:       /// subclasses.
deba@1414: 
deba@1414:       virtual void add(const std::vector<Item>& items) {
deba@1414: 	for (int i = 0; i < (int)items.size(); ++i) {
deba@1414: 	  add(items[i]);
deba@1414: 	}
deba@1414:       }
klao@946: 
klao@946:       /// \brief The member function to notificate the observer about an
klao@946:       /// item is erased from the container.
klao@946:       ///
klao@946:       /// The erase() member function notificates the observer about an
klao@946:       /// item is erased from the container. It have to be overrided in
klao@946:       /// the subclasses.
klao@946: 	
klao@946:       virtual void erase(const Item&) = 0;
klao@946: 
deba@1718:       /// \brief The member function to notificate the observer about 
deba@1718:       /// more item is erased from the container.
deba@1718:       ///
deba@1718:       /// The erase() member function notificates the observer about more item
deba@1718:       /// is erased from the container. It have to be overrided in the
deba@1718:       /// subclasses.
deba@1414:       virtual void erase(const std::vector<Item>& items) {
deba@1414: 	for (int i = 0; i < (int)items.size(); ++i) {
deba@1701: 	  erase(items[i]);
deba@1414: 	}
deba@1414:       }
deba@1414: 
klao@946:       /// \brief The member function to notificate the observer about the
alpar@1204:       /// container is built.
klao@946:       ///
klao@946:       /// The build() member function notificates the observer about the
alpar@1204:       /// container is built from an empty container. It have to be
klao@946:       /// overrided in the subclasses.
klao@946: 
klao@946:       virtual void build() = 0;
klao@946: 
klao@946:       /// \brief The member function to notificate the observer about all
klao@946:       /// items are erased from the container.
klao@946:       ///
klao@946:       /// The clear() member function notificates the observer about all
klao@946:       /// items are erased from the container. It have to be overrided in
klao@946:       /// the subclasses.
klao@946:       
klao@946:       virtual void clear() = 0;
klao@946: 
klao@946:     };
klao@946: 	
klao@946:   protected:
klao@946: 	
klao@946: 
klao@946:     typedef std::vector<ObserverBase*> Container; 
klao@946: 
klao@946:     Container container;
klao@946: 
klao@946: 		
klao@946:   public:
klao@946: 
klao@946:     /// Default constructor.
klao@946: 	
klao@946:     ///
deba@1038:     /// The default constructor of the AlterationNotifier. 
klao@946:     /// It creates an empty registry.
deba@1038:     AlterationNotifier() {}
klao@946: 
deba@1038:     /// Copy Constructor of the AlterationNotifier. 
klao@946: 	
deba@1038:     /// Copy constructor of the AlterationNotifier. 
klao@946:     /// It creates only an empty registry because the copiable
klao@946:     /// registry's observers have to be registered still into that registry.
deba@1039:     AlterationNotifier(const AlterationNotifier&) {}
klao@946: 
klao@946:     /// Assign operator.
klao@946: 		
deba@1038:     /// Assign operator for the AlterationNotifier. 
deba@1040:     /// It makes the notifier only empty because the copiable
deba@1040:     /// notifier's observers have to be registered still into that registry.
deba@1039:     AlterationNotifier& operator=(const AlterationNotifier&) {
klao@946:       typename Container::iterator it;
klao@946:       for (it = container.begin(); it != container.end(); ++it) {
klao@946: 	(*it)->registry = 0;
klao@946:       }
klao@946:     }
klao@946: 
klao@946:     /// Destructor.
klao@946: 				
deba@1038:     /// Destructor of the AlterationNotifier.
klao@946:     ///
deba@1038:     ~AlterationNotifier() {
klao@946:       typename Container::iterator it;
klao@946:       for (it = container.begin(); it != container.end(); ++it) {
klao@946: 	(*it)->registry = 0;
klao@946:       }
klao@946:     }
klao@946: 	
klao@946: 	
klao@946:   protected:
klao@946: 
klao@946:     void attach(ObserverBase& observer) {
klao@946:       container.push_back(&observer);
klao@946:       observer.registry = this;
klao@946:       observer.registry_index = container.size()-1;
klao@946:     } 
klao@946: 
klao@946:     void detach(ObserverBase& base) {
klao@946:       container.back()->registry_index = base.registry_index; 
klao@946:       container[base.registry_index] = container.back();
klao@946:       container.pop_back();
klao@946:       base.registry = 0;
klao@946:     }
klao@946: 
klao@946:   public:
klao@946: 	
deba@1414:     /// \brief Notifies all the registered observers about an Item added to 
deba@1414:     /// the container.
deba@1414:     ///
deba@1414:     /// It notifies all the registered observers about an Item added to 
deba@1414:     /// the container.
klao@946:     /// 
deba@1414:     void add(const Item& item) {
klao@946:       typename Container::iterator it;
deba@1979:       try {
deba@1979:         for (it = container.begin(); it != container.end(); ++it) {
deba@1979:           (*it)->add(item);
deba@1979:         }
deba@1979:       } catch (...) {
deba@1979:         typename Container::iterator jt;
deba@1979:         for (jt = container.begin(); jt != it; ++it) {
deba@1979:           (*it)->erase(item);
deba@1979:         }
deba@1979:         throw;
klao@946:       }
klao@946:     }	
klao@946: 
deba@1414:     /// \brief Notifies all the registered observers about more Item added to 
deba@1414:     /// the container.
deba@1414:     ///
deba@1414:     /// It notifies all the registered observers about more Item added to 
deba@1414:     /// the container.
deba@1414:     /// 
deba@1414:     void add(const std::vector<Item>& items) {
deba@1414:       typename Container::iterator it;
deba@1979:       try {
deba@1979:         for (it = container.begin(); it != container.end(); ++it) {
deba@1979:           (*it)->add(items);
deba@1979:         }
deba@1979:       } catch (...) {
deba@1979:         typename Container::iterator jt;
deba@1979:         for (jt = container.begin(); jt != it; ++it) {
deba@1979:           (*it)->erase(items);
deba@1979:         }
deba@1979:         throw;
deba@1414:       }
deba@1414:     }	
deba@1414: 
deba@1414:     /// \brief Notifies all the registered observers about an Item erased from 
deba@1414:     /// the container.
deba@1414:     ///	
deba@1414:     /// It notifies all the registered observers about an Item erased from 
deba@1414:     /// the container.
klao@946:     /// 
klao@946:     void erase(const Item& key) {
klao@946:       typename Container::iterator it;
klao@946:       for (it = container.begin(); it != container.end(); ++it) {
klao@946: 	(*it)->erase(key);
klao@946:       }
klao@946:     }
deba@1414: 
deba@1414:     /// \brief Notifies all the registered observers about more Item erased  
deba@1414:     /// from the container.
deba@1414:     ///	
deba@1414:     /// It notifies all the registered observers about more Item erased from 
deba@1414:     /// the container.
deba@1414:     /// 
deba@1414:     void erase(const std::vector<Item>& items) {
deba@1414:       typename Container::iterator it;
deba@1414:       for (it = container.begin(); it != container.end(); ++it) {
deba@1414: 	(*it)->erase(items);
deba@1414:       }
deba@1414:     }
klao@946: 
deba@1414:     /// \brief Notifies all the registered observers about the container is 
deba@1414:     /// built.
deba@1414:     ///		
alpar@1204:     /// Notifies all the registered observers about the container is built
klao@946:     /// from an empty container.
klao@946:     void build() {
klao@946:       typename Container::iterator it;
deba@1979:       try {
deba@1979:         for (it = container.begin(); it != container.end(); ++it) {
deba@1979:           (*it)->build();
deba@1979:         }
deba@1979:       } catch (...) {
deba@1979:         typename Container::iterator jt;
deba@1979:         for (jt = container.begin(); jt != it; ++it) {
deba@1979:           (*it)->clear();
deba@1979:         }
deba@1979:         throw;
klao@946:       }
klao@946:     }
klao@946: 
klao@946: 
deba@1414:     /// \brief Notifies all the registered observers about all Items are 
deba@1414:     /// erased.
deba@1414:     ///
klao@946:     /// Notifies all the registered observers about all Items are erased
klao@946:     /// from the container.
klao@946:     void clear() {
klao@946:       typename Container::iterator it;
klao@946:       for (it = container.begin(); it != container.end(); ++it) {
klao@946: 	(*it)->clear();
klao@946:       }
klao@946:     }
klao@946:   };
klao@946: 
klao@946:   
klao@946: /// @}
klao@946:   
klao@946: 
klao@946: }
klao@946: 
klao@946: #endif