Glassfish example source code file (EventSemaphore.java)

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Java - Glassfish tags/keywords

eventsemaphore, eventsemaphore, interruptedexception, interruptedexception

The Glassfish EventSemaphore.java source code

/*
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 *
 * Copyright (c) 1997-2010 Oracle and/or its affiliates. All rights reserved.
 *
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 * General Public License Version 2 only ("GPL") or the Common Development
 * and Distribution License("CDDL") (collectively, the "License").  You
 * may not use this file except in compliance with the License.  You can
 * obtain a copy of the License at
 * https://glassfish.dev.java.net/public/CDDL+GPL_1_1.html
 * or packager/legal/LICENSE.txt.  See the License for the specific
 * language governing permissions and limitations under the License.
 *
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 * file and include the License file at packager/legal/LICENSE.txt.
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 * GPL Classpath Exception:
 * Oracle designates this particular file as subject to the "Classpath"
 * exception as provided by Oracle in the GPL Version 2 section of the License
 * file that accompanied this code.
 *
 * Modifications:
 * If applicable, add the following below the License Header, with the fields
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//----------------------------------------------------------------------------
//
// Module:      EventSemaphore.java
//
// Description: Event semaphore implementation.
//
// Product:     com.sun.jts.CosTransactions
//
// Author:      Simon Holdsworth
//
// Date:        March, 1997
//
// Copyright (c):   1995-1997 IBM Corp.
//
//   The source code for this program is not published or otherwise divested
//   of its trade secrets, irrespective of what has been deposited with the
//   U.S. Copyright Office.
//
//   This software contains confidential and proprietary information of
//   IBM Corp.
//----------------------------------------------------------------------------

package com.sun.jts.CosTransactions;

/**The EventSemaphore interface provides operations that wait for and post an
 * event semaphore.
 * <p>
 * This is specifically to handle the situation where the event may have been
 * posted before the wait method is called.  This behaviour is not supported by
 * the existing wait and notify methods.
 *
 * @version 0.01
 *
 * @author Simon Holdsworth, IBM Corporation
 *
 * @see
*/
//----------------------------------------------------------------------------
// CHANGE HISTORY
//
// Version By     Change Description
//   0.01  SAJH   Initial implementation.
//-----------------------------------------------------------------------------

public class EventSemaphore {
    boolean posted = false;

    /**Default EventSemaphore constructor.
     *
     * @param
     *
     * @return
     *
     * @see
     */
    EventSemaphore() {
    }

    /**Creates the event semaphore in the given posted state.
     *
     * @param posted  Indicates whether the semaphore should be posted.
     *
     * @return
     *
     * @see
     */
    EventSemaphore( boolean posted ) {
        this.posted = posted;
    }

    /**
     * @return true if semaphore has already been posted.
     */
    synchronized public boolean isPosted() {
        return posted;
    }

    /**Waits for the event to be posted.
     * <p>
     * If the event has already been posted, then the operation returns immediately.
     *
     * @param
     *
     * @return
     *
     * @exception InterruptedException  The wait was interrupted.
     *
     * @see
     */
    synchronized public void waitEvent()
        throws InterruptedException {
        if( !posted )
            wait();
    }

    /**Posts the event semaphore.
     * <p>
     * All waiters are notified.
     *
     * @param
     *
     * @return
     *
     * @see
     */
    synchronized void post() {
        if( !posted )
            notifyAll();
        posted = true;
    }

    /**Clears a posted event semaphore.
     *
     * @param
     *
     * @return
     *
     * @see
     */
    synchronized void clear() {
        posted = false;
    }
}