/*
* ====================================================================
*
* The ObjectStyle Group Software License, Version 1.0
*
* Copyright (c) 2005 - 2006 The ObjectStyle Group and individual authors of the
* software. All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions are met: 1.
* Redistributions of source code must retain the above copyright notice, this
* list of conditions and the following disclaimer. 2. 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. 3. The end-user documentation
* included with the redistribution, if any, must include the following
* acknowlegement: "This product includes software developed by the ObjectStyle
* Group (http://objectstyle.org/)." Alternately, this acknowlegement may
* appear in the software itself, if and wherever such third-party
* acknowlegements normally appear. 4. The names "ObjectStyle Group" and
* "Cayenne" must not be used to endorse or promote products derived from this
* software without prior written permission. For written permission, please
* contact andrus@objectstyle.org. 5. Products derived from this software may
* not be called "ObjectStyle" nor may "ObjectStyle" appear in their names
* without prior written permission of the ObjectStyle Group.
*
* THIS SOFTWARE IS PROVIDED ``AS IS'' AND ANY EXPRESSED 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 THE
* OBJECTSTYLE GROUP OR ITS CONTRIBUTORS 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.
* ====================================================================
*
* This software consists of voluntary contributions made by many individuals
* on behalf of the ObjectStyle Group. For more information on the ObjectStyle
* Group, please see <http://objectstyle.org/> .
*
*/
package org.objectstyle.wolips.baseforplugins.util;
/**
* Throttle provides a mechanism for throttling back the execution of
* recurring events. Construct a Throttle with a Runnble to execute, .start()
* it, and .ping() it when events occur. After the specified sleepTime after
* the last .ping() that has occurred, the throttle will execute
*
* @author mschrag
*
*/
public class Throttle implements Runnable {
private String _name;
private Thread _throttleThread;
private boolean _running;
private boolean _stopRequested;
private int _pingCount;
private long _sleepTime;
private Runnable _runnable;
public Throttle(String name, long sleepTime, Runnable runnable) {
_name = name;
_sleepTime = sleepTime;
_runnable = runnable;
}
public synchronized int pingCount() {
return _pingCount;
}
public synchronized void ping() {
_pingCount++;
notifyAll();
}
public synchronized void start() {
if (_throttleThread == null) {
_throttleThread = new Thread(this, _name);
_throttleThread.start();
while (!_running) {
try {
wait();
} catch (InterruptedException e) {
e.printStackTrace();
}
}
}
}
public synchronized void stop() {
if (_throttleThread != null) {
_stopRequested = true;
while (_running) {
notifyAll();
try {
wait();
} catch (InterruptedException e) {
e.printStackTrace();
}
}
_stopRequested = false;
_throttleThread = null;
}
}
public void run() {
synchronized (this) {
_running = true;
notifyAll();
}
boolean running = true;
while (running) {
synchronized (this) {
try {
wait();
} catch (InterruptedException e) {
e.printStackTrace();
}
}
while (_pingCount > 0) {
int pingCount;
synchronized (this) {
pingCount = _pingCount;
}
try {
Thread.sleep(_sleepTime);
} catch (InterruptedException e) {
// ignore
}
synchronized (this) {
if (pingCount == _pingCount) {
try {
_runnable.run();
} catch (Throwable t) {
t.printStackTrace();
}
_pingCount = 0;
}
}
}
synchronized (this) {
running = !_stopRequested;
}
}
synchronized (this) {
_running = false;
notifyAll();
}
}
}