abstractworker.java

一个论坛程序的简单实现

/*
 * Copyright (c) 2003, Rafael Steil
 * 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) Neither the name of "Rafael Steil" 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 
 * THE COPYRIGHT OWNER OR 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 file creation date: Jan 29, 2004
 * net.jforum.util.concurrent.executor.AbstractWorker.java
 * The JForum Project
 * http://www.jforum.net
 * 
 * $Id: AbstractWorker.java,v 1.5 2004/10/03 16:53:54 rafaelsteil Exp $
 */
 package net.jforum.util.concurrent.executor;

import org.apache.log4j.Logger;

import net.jforum.util.concurrent.Task;

/**
 * @author Rodrigo Kumpera
 */
public abstract class AbstractWorker implements Runnable 
{
	private static final Logger logger = Logger.getLogger(AbstractWorker.class);
	protected abstract Object take() throws InterruptedException;
	
	protected void cleanup() { }
	
	public void run() 
	{
		try {
			while(true) {
				Object task = take();
				
				if(task == null) {
					break;
				}
				
				if(task instanceof Task) {
					try {
						((Task)task).execute();
					} catch(Exception e ) {
						logger.warn("Exception while executing a task: " + e);
					}
				} 
				else {
					SimpleResult sr = (SimpleResult)task;
					
					try {
						Object result = sr.getTask().execute();
						sr.setResult(result);
					} 
					catch(Exception e ) {
						sr.setException(e);
					}
				}
			}
		} 
		catch (InterruptedException e) {
			// I don't care
		} 
		finally {
			cleanup();	
		}
	}
}