ClickHouse/contrib/libpoco/Foundation/include/Poco/DynamicFactory.h

139 lines
3.5 KiB
C++
Raw Normal View History

//
// DynamicFactory.h
//
// $Id: //poco/1.4/Foundation/include/Poco/DynamicFactory.h#1 $
//
// Library: Foundation
// Package: Core
// Module: DynamicFactory
//
// Definition of the DynamicFactory class.
//
// Copyright (c) 2004-2006, Applied Informatics Software Engineering GmbH.
// and Contributors.
//
// SPDX-License-Identifier: BSL-1.0
//
#ifndef Foundation_DynamicFactory_INCLUDED
#define Foundation_DynamicFactory_INCLUDED
#include "Poco/Foundation.h"
#include "Poco/Instantiator.h"
#include "Poco/Exception.h"
#include "Poco/Mutex.h"
#include <map>
#include <memory>
namespace Poco {
template <class Base>
class DynamicFactory
/// A factory that creates objects by class name.
{
public:
typedef AbstractInstantiator<Base> AbstractFactory;
DynamicFactory()
/// Creates the DynamicFactory.
{
}
~DynamicFactory()
/// Destroys the DynamicFactory and deletes the instantiators for
/// all registered classes.
{
for (typename FactoryMap::iterator it = _map.begin(); it != _map.end(); ++it)
{
delete it->second;
}
}
Base* createInstance(const std::string& className) const
/// Creates a new instance of the class with the given name.
/// The class must have been registered with registerClass.
/// If the class name is unknown, a NotFoundException is thrown.
{
FastMutex::ScopedLock lock(_mutex);
typename FactoryMap::const_iterator it = _map.find(className);
if (it != _map.end())
return it->second->createInstance();
else
throw NotFoundException(className);
}
template <class C>
void registerClass(const std::string& className)
/// Registers the instantiator for the given class with the DynamicFactory.
/// The DynamicFactory takes ownership of the instantiator and deletes
/// it when it's no longer used.
/// If the class has already been registered, an ExistsException is thrown
/// and the instantiator is deleted.
{
registerClass(className, new Instantiator<C, Base>);
}
void registerClass(const std::string& className, AbstractFactory* pAbstractFactory)
/// Registers the instantiator for the given class with the DynamicFactory.
/// The DynamicFactory takes ownership of the instantiator and deletes
/// it when it's no longer used.
/// If the class has already been registered, an ExistsException is thrown
/// and the instantiator is deleted.
{
poco_check_ptr (pAbstractFactory);
FastMutex::ScopedLock lock(_mutex);
std::unique_ptr<AbstractFactory> ptr(pAbstractFactory);
typename FactoryMap::iterator it = _map.find(className);
if (it == _map.end())
_map[className] = ptr.release();
else
throw ExistsException(className);
}
void unregisterClass(const std::string& className)
/// Unregisters the given class and deletes the instantiator
/// for the class.
/// Throws a NotFoundException if the class has not been registered.
{
FastMutex::ScopedLock lock(_mutex);
typename FactoryMap::iterator it = _map.find(className);
if (it != _map.end())
{
delete it->second;
_map.erase(it);
}
else throw NotFoundException(className);
}
bool isClass(const std::string& className) const
/// Returns true iff the given class has been registered.
{
FastMutex::ScopedLock lock(_mutex);
return _map.find(className) != _map.end();
}
private:
DynamicFactory(const DynamicFactory&);
DynamicFactory& operator = (const DynamicFactory&);
typedef std::map<std::string, AbstractFactory*> FactoryMap;
FactoryMap _map;
mutable FastMutex _mutex;
};
} // namespace Poco
#endif // Foundation_DynamicFactory_INCLUDED