/*

* Copyright (c) 2009 Nokia Corporation and/or its subsidiary(-ies).

* All rights reserved.

* This component and the accompanying materials are made available

* under the terms of "Eclipse Public License v1.0"

* which accompanies this distribution, and is available

* at the URL "http://www.eclipse.org/legal/epl-v10.html".

*

* Initial Contributors:

* Nokia Corporation - initial contribution.

*

* Contributors:

*

* Description:

*

*/

package com.nokia.mj.impl.utils;

public final class TaskQueue

{

    Task   mFirst = null;

    Task   mLast  = null;

    boolean mIsActive = true;

    public synchronized Task getTask()

    {

        while (mIsActive)

        {

            try

            {

                Task task = getTaskImpl();

                if (task == null)

                {

                    wait();

                    task = getTaskImpl();

                }

                return task;

            }

            catch (InterruptedException ex)

            {

            }

        }

        return null;

    }

    private Task getTaskImpl()

    {

        Task task = mFirst;

        if (task != null)

        {

            if (mFirst == mLast)

            {

                mFirst = null;

                mLast = null;

            }

            else

            {

                mFirst = task.getNext();

            }

        }

        return task;

    }

    public synchronized void forcedTerminate()

    {

        mIsActive = false;

        notify();

    }

    public synchronized int addTask(Task task)

    {

        if (mIsActive)

        {

            if (mLast != null)

            {

                mLast.setNext(task);

                mLast = task;

            }

            else

            {

                // This becomes the only task in the queue.

                mFirst = task;

                mLast = task;

            }

            notify();

            return 0;

        }

        return -1;

    }

}