plasma-framework/plasma/private/dataenginemanager_p.h
2013-01-30 13:43:33 +01:00

100 lines
3.0 KiB
C++

/*
* Copyright 2006-2007 Aaron Seigo <aseigo@kde.org>
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU Library General Public License as
* published by the Free Software Foundation; either version 2, or
* (at your option) any later version.
*
* This program 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 Library General Public
* License along with this program; if not, write to the
* Free Software Foundation, Inc.,
* 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
*/
#ifndef PLASMA_DATAENGINEMANAGER_H
#define PLASMA_DATAENGINEMANAGER_H
#include <QtCore/QHash>
#include <kplugininfo.h>
#include <plasma/dataengine.h>
namespace Plasma
{
class DataEngineManagerPrivate;
/**
* @class DataEngineManager plasma/dataenginemanager.h <Plasma/DataEngineManager>
*
* @short DataEngine loader and life time manager
*
* Plasma::DataEngineManager provides facilities for listing, loading and
* according to reference count unloading of DataEngines.
**/
class PLASMA_EXPORT DataEngineManager: public QObject
{
Q_OBJECT
public:
/**
* Singleton pattern accessor.
*/
static DataEngineManager *self();
/**
* Returns a data engine object if one is loaded and available.
* On failure, the fallback NullEngine (which does nothing and
* !isValid()) is returned.
*
* @param name the name of the engine
*/
Plasma::DataEngine *engine(const QString &name) const;
/**
* Loads a data engine and increases the reference count on it.
* This should be called once per object (or set of objects) using the
* DataEngine. Afterwards, dataEngine should be used or the return
* value cached. Call unloadDataEngine when finished with the engine.
*
* @param name the name of the engine
* @return the data engine that was loaded, or the NullEngine on failure.
*/
Plasma::DataEngine *loadEngine(const QString &name);
/**
* Decreases the reference count on the engine. If the count reaches
* zero, then the engine is deleted to save resources.
*/
void unloadEngine(const QString &name);
protected:
/**
* Reimplemented from QObject
**/
void timerEvent(QTimerEvent *event);
private:
/**
* Default constructor. The singleton method self() is the
* preferred access mechanism.
*/
DataEngineManager();
~DataEngineManager();
DataEngineManagerPrivate *const d;
friend class DataEngineManagerSingleton;
};
} // namespace Plasma
#endif // multiple inclusion guard