poco/Util/include/Poco/Util/Subsystem.h
2017-09-09 11:14:06 +02:00

99 lines
2.5 KiB
C++

//
// Subsystem.h
//
// Library: Util
// Package: Application
// Module: Subsystem
//
// Definition of the Subsystem class.
//
// Copyright (c) 2004-2006, Applied Informatics Software Engineering GmbH.
// and Contributors.
//
// SPDX-License-Identifier: BSL-1.0
//
#ifndef Util_Subsystem_INCLUDED
#define Util_Subsystem_INCLUDED
#include "Poco/Util/Util.h"
#include "Poco/RefCountedObject.h"
namespace Poco {
namespace Util {
class Application;
class OptionSet;
class Util_API Subsystem: public Poco::RefCountedObject
/// Subsystems extend an application in a modular way.
///
/// The Subsystem class provides a common interface
/// for subsystems so that subsystems can be automatically
/// initialized at startup and uninitialized at shutdown.
///
/// Subsystems should also support dynamic reconfiguration,
/// so that they can be reconfigured anytime during the
/// life of a running application.
///
/// The degree to which dynamic reconfiguration is supported
/// is up to the actual subsystem implementation. It can
/// range from ignoring the reconfiguration request (not
/// recommended), to changing certain settings that affect
/// the performance, to a complete reinitialization.
{
public:
Subsystem();
/// Creates the Subsystem.
virtual const char* name() const = 0;
/// Returns the name of the subsystem.
/// Must be implemented by subclasses.
protected:
virtual void initialize(Application& app) = 0;
/// Initializes the subsystem.
virtual void uninitialize() = 0;
/// Uninitializes the subsystem.
virtual void reinitialize(Application& app);
/// Re-initializes the subsystem.
///
/// The default implementation just calls
/// uninitialize() followed by initialize().
/// Actual implementations might want to use a
/// less radical and possibly more performant
/// approach.
virtual void defineOptions(OptionSet& options);
/// Called before the Application's command line processing begins.
/// If a subsystem wants to support command line arguments,
/// it must override this method.
/// The default implementation does not define any options.
///
/// To effectively handle options, a subsystem should either bind
/// the option to a configuration property or specify a callback
/// to handle the option.
virtual ~Subsystem();
/// Destroys the Subsystem.
friend class Application;
private:
Subsystem(const Subsystem&);
Subsystem& operator = (const Subsystem&);
};
} } // namespace Poco::Util
#endif // Util_Subsystem_INCLUDED