observer.h

This software aims to create an applet and panel tools to manage a wireless interface card, such as

//
// Observer.h
//
// $Id: //poco/Main/Foundation/include/Foundation/Observer.h#5 $
//
// Definition of the Observer class.
//
// Copyright (c) 2004, Guenter Obiltschnig/Applied Informatics.
// All rights reserved.
// 
// Redistribution and use in source and binary forms, with or without
// modification, are permitted provided that the following conditions
// are met:
// 
// 1. Redistributions of source code must retain the above copyright
//    notice, this list of conditions and the following disclaimer.
// 
// 2. Redistributions in binary form must reproduce the above copyright
//    notice, this list of conditions and the following disclaimer in the
//    documentation and/or other materials provided with the distribution.
// 
// 3. Redistributions in any form must be accompanied by information on
//    how to obtain complete source code for this software and any
//    accompanying software that uses this software.  The source code
//    must either be included in the distribution or be available for no
//    more than the cost of distribution plus a nominal fee, and must be
//    freely redistributable under reasonable conditions.  For an
//    executable file, complete source code means the source code for all
//    modules it contains.  It does not include source code for modules or
//    files that typically accompany the major components of the operating
//    system on which the executable file runs.
// 
// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
// "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
// LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
// FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
// COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
// INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
// BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
// LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
// CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
// LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN
// ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
// POSSIBILITY OF SUCH DAMAGE.
//


#ifndef Foundation_Observer_INCLUDED
#define Foundation_Observer_INCLUDED


#ifndef Foundation_Foundation_INCLUDED
#include "Foundation/Foundation.h"
#endif
#ifndef Foundation_Notification_INCLUDED
#include "Foundation/Notification.h"
#endif


Foundation_BEGIN


class Foundation_API AbstractObserver
	/// The base class for all instantiations of
	/// the Observer template class.
{
public:
	AbstractObserver();
	AbstractObserver(const AbstractObserver& observer);
	virtual ~AbstractObserver();
	
	AbstractObserver& operator = (const AbstractObserver& observer);

	virtual void notify(Notification* pNf) const = 0;
	virtual bool equals(const AbstractObserver& observer) const = 0;
	virtual AbstractObserver* clone() const = 0;
};


template <class C, class N>
class Observer: public AbstractObserver
	/// This template class implements an adapter that sits between
	/// a NotificationCenter and an object receiving notifications
	/// from it. It is quite similar in concept to the 
	/// RunnableAdapter, but provides some NotificationCenter
	/// specific additional methods.
	/// See the NotificationCenter class for information on how
	/// to use this template class.
{
public:
	typedef void (C::*Callback)(N*);

	Observer(C& object, Callback method): _pObject(&object), _method(method)
	{
	}
	
	Observer(const Observer& observer): _pObject(observer._pObject), _method(observer._method)
	{
	}
	
	~Observer()
	{
	}
	
	Observer& operator = (const Observer& observer)
	{
		if (&observer != this)
		{
			_pObject = observer._pObject;
			_method  = observer._method;
		}
		return *this;
	}
	
	void notify(Notification* pNf) const
	{
		N* pCastNf = dynamic_cast<N*>(pNf);
		if (pCastNf)
		{
			pCastNf->duplicate();
			(_pObject->*_method)(pCastNf);
		}
	}
	
	bool equals(const AbstractObserver& abstractObserver) const
	{
		const Observer* pObs = dynamic_cast<const Observer*>(&abstractObserver);
		return pObs && pObs->_pObject == _pObject && pObs->_method == _method;
	}

	AbstractObserver* clone() const
	{
		return new Observer(*this);
	}
	
private:
	Observer();

	C*       _pObject;
	Callback _method;
};


Foundation_END


#endif // Foundation_Observer_INCLUDED