109 lines
2.7 KiB
C++
109 lines
2.7 KiB
C++
/*
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* Copyright (c) 2007 INRIA
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*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License version 2 as
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* published by the Free Software Foundation;
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with this program; if not, write to the Free Software
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* Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
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*
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* Author: Mathieu Lacage <mathieu.lacage@sophia.inria.fr>
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*/
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#ifndef SINGLETON_H
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#define SINGLETON_H
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/**
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* \file
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* \ingroup access
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* ns3::Singleton declaration and template implementation.
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*/
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namespace ns3
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{
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/**
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* \ingroup access
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* \brief A template singleton
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*
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* This template class can be used to implement the singleton pattern.
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* The underlying object will be destroyed automatically when the process
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* exits.
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*
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* For a singleton whose lifetime is bounded by the simulation run,
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* not the process, see SimulationSingleton.
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*
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* To force your `class ExampleS` to be a singleton, inherit from Singleton:
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* \code
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* class ExampleS : public Singleton<ExampleS> { ... };
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* \endcode
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*
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* Then, to reach the singleton instance, just do
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* \code
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* ExampleS::Get ()->...;
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* \endcode
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*
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* \note
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* If you call Get() again after the object has
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* been destroyed, the object will be re-created which will result in a
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* memory leak as reported by most memory leak checkers. It is up to the
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* user to ensure that Get() is never called from a static variable
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* finalizer.
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*/
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template <typename T>
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class Singleton
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{
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public:
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// Delete copy constructor and assignment operator to avoid misuse
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Singleton<T>(const Singleton<T>&) = delete;
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Singleton<T>& operator=(const Singleton<T>&) = delete;
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/**
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* Get a pointer to the singleton instance.
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*
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* The instance will be automatically deleted when
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* the process exits.
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*
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* \return A pointer to the singleton instance.
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*/
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static T* Get();
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protected:
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/** Constructor. */
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Singleton<T>()
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{
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}
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/** Destructor. */
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virtual ~Singleton<T>()
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{
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}
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};
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} // namespace ns3
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/********************************************************************
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* Implementation of the templates declared above.
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********************************************************************/
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namespace ns3
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{
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template <typename T>
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T*
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Singleton<T>::Get()
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{
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static T object;
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return &object;
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}
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} // namespace ns3
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#endif /* SINGLETON_H */
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