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- /*****************************************************************************
- * observer.hpp
- *****************************************************************************
- * Copyright (C) 2003 VideoLAN
- * $Id: observer.hpp 6961 2004-03-05 17:34:23Z sam $
- *
- * Authors: Cyril Deguet <asmax@via.ecp.fr>
- * Olivier Teuli鑢e <ipkiss@via.ecp.fr>
- *
- * This program is free software; you can redistribute it and/or modify
- * it under the terms of the GNU General Public License as published by
- * the Free Software Foundation; either version 2 of the License, or
- * (at your option) any later version.
- *
- * This program is distributed in the hope that it will be useful,
- * but WITHOUT ANY WARRANTY; without even the implied warranty of
- * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
- * GNU General Public License for more details.
- *
- * You should have received a copy of the GNU General Public License
- * along with this program; if not, write to the Free Software
- * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111, USA.
- *****************************************************************************/
- #ifndef OBSERVER_HPP
- #define OBSERVER_HPP
- #include <set>
- // Forward declaration
- template <class S> class Observer;
- /// Template for subjects in the Observer design pattern
- template <class S> class Subject
- {
- public:
- virtual ~Subject() {}
- /// Remove all observers; should only be used for debugging purposes
- virtual void clearObservers()
- {
- m_observers.clear();
- }
- /// Add an observer to this subject
- /// Note: adding twice the same observer is not harmful
- virtual void addObserver( Observer<S>* pObserver )
- {
- m_observers.insert( pObserver );
- }
- /// Remove an observer from this subject
- /// Note: removing twice the same observer is not harmful
- virtual void delObserver( Observer<S>* pObserver )
- {
- m_observers.erase( pObserver );
- }
- /// Notify the observers when the status has changed
- virtual void notify()
- {
- // This stupid gcc 3.2 needs "typename"
- typename set<Observer<S>*>::const_iterator iter;
- for( iter = m_observers.begin(); iter != m_observers.end();
- iter++ )
- {
- if( *iter == NULL )
- {
- fprintf( stderr, "iter NULL !n" );
- return;
- }
- (*iter)->onUpdate( *this );
- }
- }
- protected:
- Subject() {}
- private:
- /// Set of observers for this subject
- set<Observer<S>*> m_observers;
- };
- /// Template for observers in the Observer design pattern
- template <class S> class Observer
- {
- public:
- virtual ~Observer() {}
- /// Method called when the subject is modified
- virtual void onUpdate( Subject<S> &rSubject ) = 0;
- protected:
- Observer() {}
- };
- #endif
