You can not select more than 25 topics
Topics must start with a letter or number, can include dashes ('-') and can be up to 35 characters long.
100 lines
2.9 KiB
100 lines
2.9 KiB
/*****************************************************************************
|
|
* observer.hpp
|
|
*****************************************************************************
|
|
* Copyright (C) 2003 VideoLAN
|
|
* $Id$
|
|
*
|
|
* Authors: Cyril Deguet <asmax@via.ecp.fr>
|
|
* Olivier Teulière <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
|
|
|