Global.h

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/***************************************************************************
 *
 * Copyright (C) 2009-2010 Cassio Neri Moreira
 *
 * This file is part of the KeyValue library.
 *
 * The KeyValue library 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.
 *
 * The KeyValue library 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 KeyValue. If not, see <http://www.gnu.org/licenses/>.
 *
 * If you modify this library, or any covered work, by linking or combining
 * it with Excel (or a modified version of that program), containing parts
 * covered by the terms of End-User License Agreement for Microsoft
 * Software, the licensors of KeyValue grant you additional permission to
 * convey the resulting work.
 *
 **************************************************************************/

#ifndef KEYVALUE_UTIL_GLOBAL_H_
#define KEYVALUE_UTIL_GLOBAL_H_

#include <boost/utility.hpp>

#include "keyvalue/extern/SharedPtr.h"
#include "keyvalue/sys/exception/KV_ASSERT.h"

namespace keyvalue {
namespace util {

template <typename ObjectType>
class Global : private boost::noncopyable {

public:

  static shared_ptr<ObjectType>
  get();

  static void
  set(shared_ptr<ObjectType> object);

private:

  Global();

  static Global&
  getInstance();

  shared_ptr<ObjectType> object_;

}; // class Global

/*--------------------------------------------------------------------------
 * get()
 *------------------------------------------------------------------------*/

template <typename ObjectType>
shared_ptr<ObjectType>
Global<ObjectType>::get() {
  KV_ASSERT(getInstance().object_, "Called unitialized global object!");
  return getInstance().object_;
}

/*--------------------------------------------------------------------------
 * set()
 *------------------------------------------------------------------------*/

template <typename ObjectType>
void
Global<ObjectType>::set(shared_ptr<ObjectType> object) {
  getInstance().object_ = object;
}

/*--------------------------------------------------------------------------
 * Global()
 *------------------------------------------------------------------------*/

template <typename ObjectType>
Global<ObjectType>::Global() : object_(make_shared<ObjectType>()) {
}

/*--------------------------------------------------------------------------
 * getInstance()
 *------------------------------------------------------------------------*/

template <typename ObjectType>
Global<ObjectType>&
Global<ObjectType>::getInstance() {
  static Global<ObjectType> singleton;
  return singleton;
}

} // namespace util
} // namespace keyvalue

#endif // KEYVALUE_UTIL_GLOBAL_H_