/*
 * Copyright (c) 2003 - 2007 Israfil Consulting Services Corporation
 * Copyright (c) 2003 - 2007 Christian Edward Gruber
 * All Rights Reserved
 * 
 * This software is licensed under the Berkeley Standard Distribution license,
 * (BSD license), as defined below:
 * 
 * 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 Israfil Consulting Services 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.
 * 
 * $Id: RepeatingWorker.java 367 2007-01-22 23:02:28Z cgruber $
 */
package net.israfil.foundation.concurrent;

import java.util.logging.Level;
import java.util.logging.Logger;

/**
 * A Worker sub-class that implements a slightly different lifecycle.  In 
 * particular, it iterates based on a continuProcessing() signalling method.
 * It also implements pre and post processing logic in case any per-iteration
 * setup and tear-down is required. 
 * 
 * 
 * @author <a href="mailto:cgruber@israfil.net">Christian Edward Gruber </a>
 */
public abstract class RepeatingWorker extends AbstractWorker {
	
	private static Logger logger = Logger.getLogger(RepeatingWorker.class.getName());
	
	public RepeatingWorker() { }
	
	public RepeatingWorker(String name) { super(name); }
		
	public void executeLifecycle() throws InterruptedException {
		do {		
			logger.finer(getName() + " about to pre-process.");
			preProcess();
			logger.finer(getName() + " completed pre-processing.");
			logger.finer(getName() + " about to process.");
			process();
			logger.finer(getName() + " completed processing.");
			logger.finer(getName() + " about to post-process.");
			postProcess();
			logger.finer(getName() + " completed post-processing.");
			Thread.yield();
		} while (continueProcessing() && delay());
	}
	
	public abstract boolean continueProcessing() throws InterruptedException;
	
	/**
	 * @return long Number of milliseconds to delay between iterations
	 */
	public abstract long iterationDelay();
	
	/** 
	 * Returns boolean only so it can be used in a while statement. delay()
	 * simply sleeps as long as iterationDelay() indicates, then returns true,
	 * unless interrupted in which case it returns false.
	 */
	private boolean delay() {
		try {
			Thread.sleep(iterationDelay());
			return true;
		} catch (InterruptedException e) { 
			logger.log(Level.WARNING, getName() + " interrupted.",e);
			return false; 
		}
	}
	
	public void preProcess() { }
		
	public void postProcess() { }
	
}