/source/library/Interlace/Threads/WorkerThreadPool.cs

#region Using Directives and Copyright Notice



// Copyright (c) 2007-2010, Computer Consultancy Pty Ltd

// All rights reserved.

// 

// Redistribution and use in source and binary forms, with or without

// modification, are permitted provided that the following conditions are met:

//     * Redistributions of source code must retain the above copyright

//       notice, this list of conditions and the following disclaimer.

//     * Redistributions in binary form must reproduce the above copyright

//       notice, this list of conditions and the following disclaimer in the

//       documentation and/or other materials provided with the distribution.

//     * Neither the name of the Computer Consultancy Pty Ltd nor the

//       names of its contributors may be used to endorse or promote products

//       derived from this software without specific prior written permission.

// 

// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" 

// AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 

// IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 

// ARE DISCLAIMED. IN NO EVENT SHALL COMPUTER CONSULTANCY PTY LTD BE LIABLE 

// FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 

// DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR 

// SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER 

// CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 

// LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 

// OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH

// DAMAGE.



using System;

using System.Collections.Generic;

using System.Text;

using System.Threading;



using Interlace.Logging;



#endregion



namespace Interlace.Threads

{

    public delegate WorkerThread CreateWorkerThreadDelegate();



    public class WorkerThreadPool

    {

        private SynchronisedQueue _readyQueue;

        private CreateWorkerThreadDelegate _workerConstructor;



        private List<WorkerThread> _workerThreads = new List<WorkerThread>();



        private bool _running;



        public WorkerThreadPool(CreateWorkerThreadDelegate workerConstructor, int poolSize)

        {

            _workerConstructor = workerConstructor;



            _readyQueue = new SynchronisedQueue(poolSize);



            for (int i = 0; i <= poolSize - 1; i++)

            {

                CreateWorker();

            }



            _running = true;

        }



        public void QueueRequest(object request)

        {

            if (!_running)

            {

                throw new InvalidOperationException("A request can not be queued once the " + 

                    "thread pool has been shut down.");

            }



            WorkerThread thread = (WorkerThread)_readyQueue.Dequeue(Timeout.Infinite);



            thread.AcceptRequest(request);

        }



        /// <summary>

        /// Shuts down the pool of workers. A pool instance becomes unusable once it is shut down.

        /// </summary>

        public void Shutdown()

        {

            if (_running)

            {

                _running = false;



                foreach (WorkerThread thread in _workerThreads)

                {

                    thread.Shutdown();

                }

            }

        }



        private void CreateWorker()

        {

            WorkerThread worker = _workerConstructor();



            _readyQueue.Enqueue(worker, Timeout.Infinite);

            _workerThreads.Add(worker);



            worker.Attach(this);

            worker.CreateThread();

        }



        internal void RequestCompleted(WorkerThread worker)

        {

            _readyQueue.Enqueue(worker, Timeout.Infinite);

        }

    }

}