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

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//
// ActiveDispatcher.h
//
// $Id: //poco/1.4/Foundation/include/Poco/ActiveDispatcher.h#1 $
//
// Library: Foundation
// Package: Threading
// Module: ActiveObjects
//
// Definition of the ActiveDispatcher class.
//
// Copyright (c) 2006-2007, Applied Informatics Software Engineering GmbH.
// and Contributors.
//
// SPDX-License-Identifier: BSL-1.0
//
#ifndef Foundation_ActiveDispatcher_INCLUDED
#define Foundation_ActiveDispatcher_INCLUDED
#include "Poco/Foundation.h"
#include "Poco/Runnable.h"
#include "Poco/Thread.h"
#include "Poco/ActiveStarter.h"
#include "Poco/ActiveRunnable.h"
#include "Poco/NotificationQueue.h"
namespace Poco {
class Foundation_API ActiveDispatcher: protected Runnable
/// This class is used to implement an active object
/// with strictly serialized method execution.
///
/// An active object, which is an ordinary object
/// containing ActiveMethod members, executes all
/// active methods in their own thread.
/// This behavior does not fit the "classic"
/// definition of an active object, which serializes
/// the execution of active methods (in other words,
/// only one active method can be running at any given
/// time).
///
/// Using this class as a base class, the serializing
/// behavior for active objects can be implemented.
///
/// The following example shows how this is done:
///
/// class ActiveObject: public ActiveDispatcher
/// {
/// public:
/// ActiveObject():
/// exampleActiveMethod(this, &ActiveObject::exampleActiveMethodImpl)
/// {
/// }
///
/// ActiveMethod<std::string, std::string, ActiveObject, ActiveStarter<ActiveDispatcher> > exampleActiveMethod;
///
/// protected:
/// std::string exampleActiveMethodImpl(const std::string& arg)
/// {
/// ...
/// }
/// };
///
/// The only things different from the example in
/// ActiveMethod is that the ActiveObject in this case
/// inherits from ActiveDispatcher, and that the ActiveMethod
/// template for exampleActiveMethod has an additional parameter,
/// specifying the specialized ActiveStarter for ActiveDispatcher.
{
public:
ActiveDispatcher();
/// Creates the ActiveDispatcher.
ActiveDispatcher(Thread::Priority prio);
/// Creates the ActiveDispatcher and sets
/// the priority of its thread.
virtual ~ActiveDispatcher();
/// Destroys the ActiveDispatcher.
void start(ActiveRunnableBase::Ptr pRunnable);
/// Adds the Runnable to the dispatch queue.
void cancel();
/// Cancels all queued methods.
protected:
void run();
void stop();
private:
Thread _thread;
NotificationQueue _queue;
};
template <>
class ActiveStarter<ActiveDispatcher>
/// A specialization of ActiveStarter
/// for ActiveDispatcher.
{
public:
static void start(ActiveDispatcher* pOwner, ActiveRunnableBase::Ptr pRunnable)
{
pOwner->start(pRunnable);
}
};
} // namespace Poco
#endif // Foundation_ActiveDispatcher_INCLUDED