com.mchange.v1.lang.GentleThread Maven / Gradle / Ivy
/*
* Distributed as part of mchange-commons-java 0.2.11
*
* Copyright (C) 2015 Machinery For Change, Inc.
*
* Author: Steve Waldman
*
* This library is free software; you can redistribute it and/or modify
* it under the terms of EITHER:
*
* 1) The GNU Lesser General Public License (LGPL), version 2.1, as
* published by the Free Software Foundation
*
* OR
*
* 2) The Eclipse Public License (EPL), version 1.0
*
* You may choose which license to accept if you wish to redistribute
* or modify this work. You may offer derivatives of this work
* under the license you have chosen, or you may provide the same
* choice of license which you have been offered here.
*
* This software is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
*
* You should have received copies of both LGPL v2.1 and EPL v1.0
* along with this software; see the files LICENSE-EPL and LICENSE-LGPL.
* If not, the text of these licenses are currently available at
*
* LGPL v2.1: http://www.gnu.org/licenses/old-licenses/lgpl-2.1.html
* EPL v1.0: http://www.eclipse.org/org/documents/epl-v10.php
*
*/
package com.mchange.v1.lang;
/**
* an abstract Thread class that provides
* utilities for easily defining Threads with
* safe versions of the deprecated thread
* methods stop(), resume(), and start()
*/
public abstract class GentleThread extends Thread
{
boolean should_stop = false;
boolean should_suspend = false;
public GentleThread()
{ super(); }
public GentleThread(String name)
{ super( name ); }
public abstract void run();
/**
* a safe method for stopping properly implemented GentleThreads
*/
public synchronized void gentleStop()
{should_stop = true;}
/**
* a safe method for suspending properly implemented GentleThreads
*/
public synchronized void gentleSuspend()
{should_suspend = true;}
/**
* a safe method for resuming properly implemented GentleThreads
*/
public synchronized void gentleResume()
{
should_suspend = false;
this.notifyAll();
}
/**
* tests whether the thread should stop.
* Subclasses should call this method periodically in
* their run method, and return from run() is the
* method returns true.
*/
protected synchronized boolean shouldStop()
{return should_stop;}
/**
* tests whether the thread should suspend.
* Subclasses rarely call this method directly,
* and should call allowSuspend() periodically
* instead.
*
* @see #allowSuspend
*/
protected synchronized boolean shouldSuspend()
{return should_suspend;}
/**
* tests whether the thread should suspend,
* and causes to the thread to pause if appropriate.
* Subclasses should call this method periodically
* in their run method to, um, allow suspension.
* Threads paused by allowSuspend() will be properly
* awoken by gentleResume()
*
* @see #gentleResume
*/
protected synchronized void allowSuspend() throws InterruptedException
{while (should_suspend) this.wait();}
}