interruptablejob.java

来自「定时器开源项目, 相对于 jcrontab, Quartz 算是更完整的一个项目」· Java 代码 · 共 86 行

/*
 * Copyright James House (c) 2001-2004
 * 
 * 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.
 * 
 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR 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 AUTHOR 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.
 *  
 */
package org.quartz;

/**
 * <p>
 * The interface to be implemented by <code>{@link Job}s</code> that provide a 
 * mechanism for having their execution interrupted.  It is NOT a requirment
 * for jobs to implement this interface - in fact, for most people, none of
 * their jobs will.
 * </p>
 * 
 * <p>
 * The means of actually interrupting the Job must be implemented within the
 * <code>Job</code> itself (the <code>interrupt()</code> method of this 
 * interface is simply a means for the scheduler to inform the <code>Job</code>
 * that a request has been made for it to be interrupted). The mechanism that
 * your jobs use to interrupt themselves might vary between implementations.
 * However the principle idea in any implementation should be to have the
 * body of the job's <code>execute(..)</code> periodically check some flag to
 * see if an interruption has been requested, and if the flag is set, somehow
 * abort the performance of the rest of the job's work.  An example of 
 * interrupting a job can be found in the java source for the  class 
 * <code>org.quartz.examples.DumbInterruptableJob</code>.  It is legal to use
 * some combination of <code>wait()</code> and <code>notify()</code> 
 * synchronization within <code>interrupt()</code> and <code>execute(..)</code>
 * in order to have the <code>interrupt()</code> method block until the
 * <code>execute(..)</code> signals that it has noticed the set flag.
 * </p>
 * 
 * @see Job
 * @see StatefulJob
 * @see Scheduler#interrupt(String, String)
 * @see org.quartz.examples.DumbInterruptableJob
 * 
 * @author James House
 */
public interface InterruptableJob extends Job {

    /*
     * ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
     * 
     * Interface.
     * 
     * ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
     */

    /**
     * <p>
     * Called by the <code>{@link Scheduler}</code> when a user
     * interrupts the <code>Job</code>.
     * </p>
     * 
     * @return void (nothing) if job interrupt is successful.
     * @throws UnableToInterruptJobException
     *           if there is an exception while interrupting the job.
     */
    public void interrupt()
            throws UnableToInterruptJobException;

    
}