eventmanager.java

实现了Jms的服务器源码,支持多种适配器,DB,FTP,支持多种数据库

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 *    above copyright notice, this list of conditions and the
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 *
 * THIS SOFTWARE IS PROVIDED BY EXOFFICE TECHNOLOGIES AND CONTRIBUTORS
 * ``AS IS'' AND ANY EXPRESSED OR IMPLIED WARRANTIES, INCLUDING, BUT
 * NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND
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 * INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
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 * 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.
 *
 * Copyright 2000,2003 (C) Exoffice Technologies Inc. All Rights Reserved.
 *
 * $Id: EventManager.java,v 1.3 2003/08/17 01:32:22 tanderson Exp $
 *
 * Date         Author  Changes
 * 07/27/00	    jima    Created
 */
package org.exolab.jms.events;

import org.exolab.core.service.Serviceable;


/**
 * The EventManager manages {@link Event} objects. It has methods to
 * register and unregister events. It also extends {@link Runnable} interface
 * which defines the thread responsible for dispatching events.
 * <p>
 * An event is defined to occur at sometime in the future, as specified either
 * by an absolute time through {@link #registerEvent} or as relative time
 * through {@link #registerEventRelative}. An event must have an associated
 * event type and may have an attached <code>Serializable</code> object,
 * which is used when the EventManager makes a callback to the registered
 * handler when the event fires.
 * <p>
 * The register methids will return an event identifier which can subsequently
 * be used to unregister the event through the {@link #unregisterEvent} event.
 * This is the only means of unregister an event.
 * <p>
 * If the {@link Event} object is incorrectly specified then the
 * {@link IllegalEventDefinedException} exception is raised.
 * <p>
 * When an event fires the EventManager is responsible for ensuring
 * that the event handler is notified. If the event handler has since been
 * removed then the EventManager must gracefully abort the delivery and
 * continue processing the next event.
 * <p>
 * Objects of type {@link Event} need to survive subsequent
 * EventManager restarts, as such they must be persisted, which
 * implies that the {@link EventHandler} needs to also be persisted. The
 * ability to store the {@link EventHandler} as a <code>HandleIfc</code> object
 * which can later be resolved to an object will be required.
 * <p>
 * This class is also <code>Serviceable</code>, which implies that it can be 
 * added and controlled by a <code>ServiceManager</code>.
 *
 * @version     $Revision: 1.3 $ $Date: 2003/08/17 01:32:22 $
 * @author      <a href="mailto:[e-mail]">Jim Alateras</a>
 */
public interface EventManager
    extends Serviceable {

    /**
     * Register an event to be fired once and only once at the specified
     * abolsute time. The event object must be Serializable so that it can
     * be persisted and restored across EventManager restarts.
     * <p>
     * If the specified event is ill-defined then the IllegalEventDefined-
     * Exception exception is thrown.
     * <p>
     * Similarly, if the abolsute time has already passed then the exception
     * IllegalEventDefinedException is raised.
     * <p>
     * The method returns an unique event identifier, which can subsequently
     * be used to deregister the event.
     *
     * @param       event           information about the event
     * @param       abolsute        the abolsute time, in ms, that the event
     *                              must fire
     * @return      String          unique event identifier
     * @throws      IllegalEventDefinedException
     */
    String registerEvent(Event event, long absolute)
        throws IllegalEventDefinedException;

    /**
     * Register an event to be fired once and only once at a time relative to
     * now. The event object must be Serializable so that it can be persisted
     * and restored across EventManager restarts.
     * <p>
     * If the specified event is ill-defined then the IllegalEventDefined-
     * Exception exception is thrown.
     * <p>
     * The method returns an unique event identifier, which can subsequently
     * be used to deregister the event.
     *
     * @param       event           information about the event
     * @param       relative        the  relative time in ms
     *                              (currently no reference to locale).
     * @return      String          unique event identifier,
     * @throws      IllegalEventDefinedException
     */
    String registerEventRelative(Event event, long relative)
        throws IllegalEventDefinedException;

    /**
     * Unregister the event specified by the event identifier. If the event
     * does not exist then fail silently.
     *
     * @param       String          unique event identifier.
     */
    void unregisterEvent(String id);
}