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//

// 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