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ActiveDispatcher.h
//
// ActiveDispatcher.h
//
// $Id: //poco/1.3/Foundation/include/Poco/ActiveDispatcher.h#2 $
//
// Library: Foundation
// Package: Threading
// Module:  ActiveObjects
//
// Definition of the ActiveDispatcher class.
//
// Copyright (c) 2006-2007, Applied Informatics Software Engineering GmbH.
// and Contributors.
//
// Permission is hereby granted, free of charge, to any person or organization
// obtaining a copy of the software and accompanying documentation covered by
// this license (the "Software") to use, reproduce, display, distribute,
// execute, and transmit the Software, and to prepare derivative works of the
// Software, and to permit third-parties to whom the Software is furnished to
// do so, all subject to the following:
// 
// The copyright notices in the Software and this entire statement, including
// the above license grant, this restriction and the following disclaimer,
// must be included in all copies of the Software, in whole or in part, and
// all derivative works of the Software, unless such copies or derivative
// works are solely in the form of machine-executable object code generated by
// a source language processor.
// 
// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
// IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
// FITNESS FOR A PARTICULAR PURPOSE, TITLE AND NON-INFRINGEMENT. IN NO EVENT
// SHALL THE COPYRIGHT HOLDERS OR ANYONE DISTRIBUTING THE SOFTWARE BE LIABLE
// FOR ANY DAMAGES OR OTHER LIABILITY, WHETHER IN CONTRACT, TORT OR OTHERWISE,
// ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
// DEALINGS IN THE SOFTWARE.
//


#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 {


00054 class Foundation_API ActiveDispatcher: protected Runnable
      /// This class is used to implement an active object
      /// with strictly serialized method execution.
      ///
      /// An active object, with 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 <>
00123 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

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