cpcc/pattern.listener.h at master · starmessage/cpcc · GitHub

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 /*  *****************************************
 *  File:		pattern.listener.h
 *  Version:	see function getClassVersion()
 *	Purpose:	a template Listener pattern
 *	*****************************************
 *  Library:	Cross Platform C++ Classes (cpcc)
 *  Copyright: 	2013 StarMessage software.
 *  License: 	Free for opensource projects.
 *  			Commercial license for closed source projects.
 *	Web:		http://www.StarMessageSoftware.com
 *				https://github.com/starmessage/cpcc
 *	email:		sales -at- starmessage.info
 *	*****************************************
 */


#pragma once
#ifndef CPCCLISTENERPATTERN_H
#define CPCCLISTENERPATTERN_H

#include <string>
#include <set>
#include <assert.h>
#include "cpccUnicodeSupport.h"

// ---------------- class cmiListener  -----------------
template<typename Tobject>
class cpccListener
{

private:
	int _nSubscriptions;

public: // data
	cpcc_string		name;

public: // ctors
	cpccListener(const cpcc_char *aName= _T("Unnamed cpcclistener")):
		name(aName),
		_nSubscriptions(0)
	{ };

	~cpccListener()
	{
		assert((_nSubscriptions==0) && _T("#2352: destroying cpcclistener, but is still subscribed"));
	};

public: // functions

	void virtual beNotifiedAbout(Tobject &anObject) = 0;

	int getNumSubsciptions(void)	{ return _nSubscriptions; } ;

	void increaseSubscriptions(void)
	{
		assert((_nSubscriptions>=0) && _T("#5370: _nSubscriptions<0"));
		_nSubscriptions++;
	};

	void decreaseSubscriptions(void)
	{
		assert((_nSubscriptions>0) && _T("#5371: _nSubscriptions<=0"));
		_nSubscriptions--;
	};
};


template <typename Tobject>
class cpccListenersList
{
private:
	std::set<cpccListener<Tobject> *> _listenersList;

public: //constructors

	cpccListenersList()
	{
		assert(countListeners()==0 && _T("#3415 cmiListenersList constructor: Not empty list"));
	};

	~cpccListenersList()
	{
		// at this point if the program is terminating
		// you cannot have any calls to IO like std::cout << "Destructor cmiListenersList"
		assert((countListeners()==0) && _T("#5274: destroying cmiListenersList, but listeners still exist"));
	};

public: //functions

	void notifyListeners(Tobject &anObject)
	{	int n=countListeners();
		typename std::set<cpccListener<Tobject> *>::iterator itr;
		for (itr = _listenersList.begin(); itr != _listenersList.end(); itr++ )
			{
			(*itr)->beNotifiedAbout(anObject);
			n--;
			}
		assert(n==0 && _T("#8246: notifyListeners iterator did not work properly"));
	};


	void addListener(cpccListener<Tobject> & o)
	{	_listenersList.insert(&o);
		o.increaseSubscriptions();
	};

	void removeListener(cpccListener<Tobject> & o)
	{	_listenersList.erase(&o);
		o.decreaseSubscriptions();
	};


	int countListeners(void)
		{	return _listenersList.size();	};

};


#endif // CPCCLISTENERPATTERN_H