colorjob.java

Quartz 是个开源的作业调度框架

/* 
 * Copyright 2005 OpenSymphony 
 * 
 * Licensed under the Apache License, Version 2.0 (the "License"); you may not 
 * use this file except in compliance with the License. You may obtain a copy 
 * of the License at 
 * 
 *   http://www.apache.org/licenses/LICENSE-2.0 
 *   
 * Unless required by applicable law or agreed to in writing, software 
 * distributed under the License is distributed on an "AS IS" BASIS, WITHOUT 
 * WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the 
 * License for the specific language governing permissions and limitations 
 * under the License.
 * 
 */

package org.quartz.examples.example4;

import java.util.Date;

import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;
import org.quartz.JobDataMap;
import org.quartz.JobExecutionContext;
import org.quartz.JobExecutionException;
import org.quartz.StatefulJob;

/**
 * <p>
 * This is just a simple job that receives parameters and
 * maintains state
 * </p>
 * 
 * @author Bill Kratzer
 */
public class ColorJob implements StatefulJob {

	private static Log _log = LogFactory.getLog(ColorJob.class);
	
	// parameter names specific to this job
	public static final String FAVORITE_COLOR = "favorite color";
	public static final String EXECUTION_COUNT = "count";
	
	// Since Quartz will re-instantiate a class every time it
	// gets executed, members non-static member variables can
	// not be used to maintain state!
	private int _counter = 1;

	/**
	 * <p>
	 * Empty constructor for job initilization
	 * </p>
	 * <p>
	 * Quartz requires a public empty constructor so that the
	 * scheduler can instantiate the class whenever it needs.
	 * </p>
	 */
	public ColorJob() {
	}

	/**
	 * <p>
	 * Called by the <code>{@link org.quartz.Scheduler}</code> when a
	 * <code>{@link org.quartz.Trigger}</code> fires that is associated with
	 * the <code>Job</code>.
	 * </p>
	 * 
	 * @throws JobExecutionException
	 *             if there is an exception while executing the job.
	 */
	public void execute(JobExecutionContext context)
			throws JobExecutionException {

		// This job simply prints out its job name and the
		// date and time that it is running
		String jobName = context.getJobDetail().getFullName();
		
		// Grab and print passed parameters
		JobDataMap data = context.getJobDetail().getJobDataMap();
		String favoriteColor = data.getString(FAVORITE_COLOR);
		int count = data.getInt(EXECUTION_COUNT);
		_log.info("ColorJob: " + jobName + " executing at " + new Date() + "\n" +
			"  favorite color is " + favoriteColor + "\n" + 
			"  execution count (from job map) is " + count + "\n" + 
			"  execution count (from job member variable) is " + _counter);
		
		// increment the count and store it back into the 
		// job map so that job state can be properly maintained
		count++;
		data.put(EXECUTION_COUNT, count);
		
		// Increment the local member variable 
		// This serves no real purpose since job state can not 
		// be maintained via member variables!
		_counter++;
	}

}