observer.cpp

/*
 *  Copyright (C) 2004, 2005, 2006, 2009, 2008, 2009, 2010 Savoir-Faire Linux Inc.
 *  Author: Yan Morin <yan.morin@savoirfairelinux.com>
 *
 *  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 3 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., 675 Mass Ave, Cambridge, MA 02139, USA.
 *
 *  Additional permission under GNU GPL version 3 section 7:
 *
 *  If you modify this program, or any covered work, by linking or
 *  combining it with the OpenSSL project's OpenSSL library (or a
 *  modified version of that library), containing parts covered by the
 *  terms of the OpenSSL or SSLeay licenses, Savoir-Faire Linux Inc.
 *  grants you additional permission to convey the resulting work.
 *  Corresponding Source for a non-source form of such a combination
 *  shall include the source code for the parts of OpenSSL used as well
 *  as that of the covered work.
 */

#include "observer.h"
#include <algorithm>

namespace Pattern
{

void
Subject::attach (Observer& observer)
{
    if (std::find (_observers.begin(), _observers.end(), &observer) == _observers.end()) {
        _observers.push_back (&observer);
    }
}

void
Subject::detach (Observer& observer)
{
    std::list<Observer*>::iterator iter = std::find (_observers.begin(), _observers.end(), &observer);

    if (iter != _observers.end()) {
        _observers.erase (iter);
    }
}

void
Subject::notify()
{
    std::list<Observer*>::iterator iter = _observers.begin();

    while (iter != _observers.end()) {
        if (*iter) {
            (*iter)->update();
        }

        iter++;
    }
}

} // end of namespace