poco/Foundation/include/Poco/SingletonHolder.h
2006-10-23 15:48:43 +00:00

90 lines
2.6 KiB
C++

//
// SingletonHolder.h
//
// $Id: //poco/1.2/Foundation/include/Poco/SingletonHolder.h#1 $
//
// Library: Foundation
// Package: Core
// Module: SingletonHolder
//
// Definition of the SingletonHolder template.
//
// Copyright (c) 2004-2006, Applied Informatics Software Engineering GmbH.
// and Contributors.
//
// Permission is hereby granted, free of charge, to any person or organization
// obtaining a copy of the software and accompanying documentation covered by
// this license (the "Software") to use, reproduce, display, distribute,
// execute, and transmit the Software, and to prepare derivative works of the
// Software, and to permit third-parties to whom the Software is furnished to
// do so, all subject to the following:
//
// The copyright notices in the Software and this entire statement, including
// the above license grant, this restriction and the following disclaimer,
// must be included in all copies of the Software, in whole or in part, and
// all derivative works of the Software, unless such copies or derivative
// works are solely in the form of machine-executable object code generated by
// a source language processor.
//
// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
// IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
// FITNESS FOR A PARTICULAR PURPOSE, TITLE AND NON-INFRINGEMENT. IN NO EVENT
// SHALL THE COPYRIGHT HOLDERS OR ANYONE DISTRIBUTING THE SOFTWARE BE LIABLE
// FOR ANY DAMAGES OR OTHER LIABILITY, WHETHER IN CONTRACT, TORT OR OTHERWISE,
// ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
// DEALINGS IN THE SOFTWARE.
//
#ifndef Foundation_SingletonHolder_INCLUDED
#define Foundation_SingletonHolder_INCLUDED
#include "Poco/Foundation.h"
#include "Poco/Mutex.h"
namespace Poco {
template <class S>
class SingletonHolder
/// This is a helper template class for managing
/// singleton objects allocated on the heap.
/// The class ensures proper deletion (including
/// calling of the destructor) of singleton objects
/// when the application that created them terminates.
{
public:
SingletonHolder()
/// Creates the SingletonHolder.
{
_pS = 0;
}
~SingletonHolder()
/// Destroys the SingletonHolder and the singleton
/// object that it holds.
{
delete _pS;
}
S* get()
/// Returns a pointer to the singleton object
/// hold by the SingletonHolder. The first call
/// to get will create the singleton.
{
FastMutex::ScopedLock lock(_m);
if (!_pS) _pS = new S;
return _pS;
}
private:
S* _pS;
FastMutex _m;
};
} // namespace Poco
#endif // Foundation_SingletonHolder_INCLUDED