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package javax.resource.spi.work;

import java.lang.Object;
import java.lang.Runnable;
import java.lang.Exception;
import java.lang.Throwable;
import java.util.EventListener;

/**
 * This models a <code>WorkListener</code> instance which would be notified
 * by the <code>WorkManager</code> when the various <code>Work</code> 
 * processing events (work accepted, work rejected, work started, 
 * work completed) occur.
 *
 * The <code>WorkListener</code> instance must not make any thread 
 * assumptions and must be thread-safe ie., a notification could 
 * occur from any arbitrary thread. Further, it must not make any
 * assumptions on the ordering of notifications.
 *
 * @version 1.0
 * @author  Ram Jeyaraman
 */
public interface WorkListener extends EventListener {

    /** 
     * Invoked when a <code>Work</code> instance has been accepted.
     */
    void workAccepted(WorkEvent e);

    /** 
     * Invoked when a <code>Work</code> instance has been rejected.
     */
    void workRejected(WorkEvent e);

    /** 
     * Invoked when a <code>Work</code> instance has started execution.
     * This only means that a thread has been allocated.
     */
    void workStarted(WorkEvent e);

    /** 
     * Invoked when a <code>Work</code> instance has completed execution.
     */
    void workCompleted(WorkEvent e);
}