source: XMLIO_V2/external/include/Poco/Task.h @ 80

//
// Task.h
//
// $Id: //poco/1.3/Foundation/include/Poco/Task.h#1 $
//
// Library: Foundation
// Package: Tasks
// Module:  Tasks
//
// Definition of the Task class.
//
// Copyright (c) 2004-2006, 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_Task_INCLUDED
#define Foundation_Task_INCLUDED


#include "Poco/Foundation.h"
#include "Poco/Runnable.h"
#include "Poco/RefCountedObject.h"
#include "Poco/Mutex.h"
#include "Poco/Event.h"


namespace Poco {


class TaskManager;
class Notification;
class NotificationCenter;


class Foundation_API Task: public Runnable, public RefCountedObject
        /// A Task is a subclass of Runnable that has a name 
        /// and supports progress reporting and cancellation.
        ///
        /// A TaskManager object can be used to take care of the
        /// lifecycle of a Task.
{
public:
        enum TaskState
        {
                TASK_IDLE,
                TASK_STARTING,
                TASK_RUNNING,
                TASK_CANCELLING,
                TASK_FINISHED
        };
        
        Task(const std::string& name);
                /// Creates the Task.

        const std::string& name() const;
                /// Returns the task's name.    
                
        float progress() const;
                /// Returns the task's progress.
                /// The value will be between 0.0 (just started)
                /// and 1.0 (completed).

        void cancel();
                /// Requests the task to cancel itself. For cancellation
                /// to work, the task's runTask() method must periodically
                /// call isCancelled() and react accordingly.

        bool isCancelled() const;
                /// Returns true if cancellation of the task has been
                /// requested. 
                ///
                /// A Task's runTask() method should periodically
                /// call this method and stop whatever it is doing in an
                /// orderly way when this method returns true.

        TaskState state() const;
                /// Returns the task's current state.

        void reset();
                /// Sets the task's progress to zero and clears the
                /// cancel flag.
                
        virtual void runTask() = 0;
                /// Do whatever the task needs to do. Must
                /// be overridden by subclasses.
                
        void run();
                /// Calls the task's runTask() method and notifies the owner
                /// of the task's start and completion.

protected:
        bool sleep(long milliseconds);
                /// Suspends the current thread for the specified
                /// amount of time.
                ///
                /// If the task is cancelled while it is sleeping,
                /// sleep() will return immediately and the return
                /// value will be true. If the time interval
                /// passes without the task being cancelled, the
                /// return value is false.
                ///
                /// A Task should use this method in favor of Thread::sleep().

        void setProgress(float progress);
                /// Sets the task's progress.
                /// The value should be between 0.0 (just started)
                /// and 1.0 (completed).

        virtual void postNotification(Notification* pNf);
                /// Posts a notification to the task manager's
                /// notification center.
                ///
                /// A task can use this method to post custom
                /// notifications about its progress.

        void setOwner(TaskManager* pOwner);
                /// Sets the (optional) owner of the task.
                
        TaskManager* getOwner() const;
                /// Returns the owner of the task, which may be NULL.

        void setState(TaskState state);
                /// Sets the task's state.

        virtual ~Task();
                /// Destroys the Task.
                
private:
        Task();
        Task(const Task&);
        Task& operator = (const Task&);
        
        std::string       _name;
        TaskManager*      _pOwner;
        float             _progress;
        TaskState         _state;
        Event             _cancelEvent;
        mutable FastMutex _mutex;
        
        friend class TaskManager;
};


//
// inlines
//
inline const std::string& Task::name() const
{
        return _name;
}


inline float Task::progress() const
{
        FastMutex::ScopedLock lock(_mutex);

        return _progress;
}


inline bool Task::isCancelled() const
{
        return _state == TASK_CANCELLING;
}


inline Task::TaskState Task::state() const
{
        return _state;
}


inline TaskManager* Task::getOwner() const
{
        FastMutex::ScopedLock lock(_mutex);

        return _pOwner;
}


} // namespace Poco


#endif // Foundation_Task_INCLUDED