6eb49ed0d2
git-svn-id: file:///srv/devel/repo-conversion/nusu@111 d2e56fa2-650e-0410-a79f-9358c0239efd
108 lines
3.6 KiB
C#
108 lines
3.6 KiB
C#
#region CPL License
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/*
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Nuclex Framework
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Copyright (C) 2002-2009 Nuclex Development Labs
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This library is free software; you can redistribute it and/or
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modify it under the terms of the IBM Common Public License as
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published by the IBM Corporation; either version 1.0 of the
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License, or (at your option) any later version.
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This library is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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IBM Common Public License for more details.
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You should have received a copy of the IBM Common Public
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License along with this library
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*/
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#endregion
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using System;
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using System.Collections.Generic;
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using System.Diagnostics;
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using System.Threading;
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namespace Nuclex.Support.Scheduling {
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/// <summary>Operation that executes a method in a background thread</summary>
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public abstract class ThreadOperation : Operation {
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/// <summary>
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/// Initializes a new threaded operation.
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/// </summary>
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/// <remarks>
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/// Uses a ThreadPool thread to execute the method in a background thread.
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/// </remarks>
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public ThreadOperation() : this(true) { }
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/// <summary>
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/// Initializes a new threaded operation which optionally uses the ThreadPool.
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/// </summary>
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/// <param name="useThreadPool">Whether to use a ThreadPool thread.</param>
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/// <remarks>
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/// If useThreadPool is false, a new thread will be created. This guarantees
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/// that the method will be executed immediately but has an impact on
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/// performance since the creation of new threads is not a cheap operation.
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/// </remarks>
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public ThreadOperation(bool useThreadPool) {
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this.useThreadPool = useThreadPool;
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}
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/// <summary>Launches the background operation</summary>
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public override void Start() {
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Debug.Assert(
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!Ended,
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"Tried to Start an Operation again that has already ended",
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"Operations cannot be re-run"
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);
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if(useThreadPool) {
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ThreadPool.QueueUserWorkItem(callMethod);
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} else {
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Thread thread = new Thread(callMethod);
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thread.Name = "Nuclex.Support.Scheduling.ThreadOperation";
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thread.IsBackground = true;
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thread.Start();
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}
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}
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/// <summary>Contains the payload to be executed in the background thread</summary>
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protected abstract void Execute();
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/// <summary>Invokes the delegate passed as an argument</summary>
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/// <param name="state">Not used</param>
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private void callMethod(object state) {
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try {
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Execute();
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Debug.Assert(
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!Ended,
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"Operation unexpectedly ended during Execute()",
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"Do not call OnAsyncEnded() yourself when deriving from ThreadOperation"
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);
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}
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catch(Exception exception) {
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this.exception = exception;
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}
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finally {
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OnAsyncEnded();
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}
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}
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/// <summary>
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/// Allows the specific request implementation to re-throw an exception if
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/// the background process finished unsuccessfully
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/// </summary>
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protected override void ReraiseExceptions() {
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if(this.exception != null)
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throw this.exception;
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}
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/// <summary>Whether to use the ThreadPool for obtaining a background thread</summary>
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private bool useThreadPool;
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/// <summary>Exception that has occured in the background process</summary>
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private volatile Exception exception;
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}
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} // namespace Nuclex.Support.Scheduling
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