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1 /*** 2 * Redistribution and use of this software and associated documentation 3 * ("Software"), with or without modification, are permitted provided 4 * that the following conditions are met: 5 * 6 * 1. Redistributions of source code must retain copyright 7 * statements and notices. Redistributions must also contain a 8 * copy of this document. 9 * 10 * 2. Redistributions in binary form must reproduce the 11 * above copyright notice, this list of conditions and the 12 * following disclaimer in the documentation and/or other 13 * materials provided with the distribution. 14 * 15 * 3. The name "Exolab" must not be used to endorse or promote 16 * products derived from this Software without prior written 17 * permission of Exoffice Technologies. For written permission, 18 * please contact info@exolab.org. 19 * 20 * 4. Products derived from this Software may not be called "Exolab" 21 * nor may "Exolab" appear in their names without prior written 22 * permission of Exoffice Technologies. Exolab is a registered 23 * trademark of Exoffice Technologies. 24 * 25 * 5. Due credit should be given to the Exolab Project 26 * (http://www.exolab.org/). 27 * 28 * THIS SOFTWARE IS PROVIDED BY EXOFFICE TECHNOLOGIES AND CONTRIBUTORS 29 * ``AS IS'' AND ANY EXPRESSED OR IMPLIED WARRANTIES, INCLUDING, BUT 30 * NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND 31 * FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL 32 * EXOFFICE TECHNOLOGIES OR ITS CONTRIBUTORS BE LIABLE FOR ANY DIRECT, 33 * INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES 34 * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR 35 * SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 36 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, 37 * STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) 38 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED 39 * OF THE POSSIBILITY OF SUCH DAMAGE. 40 * 41 * Copyright 2000,2003 (C) Exoffice Technologies Inc. All Rights Reserved. 42 * 43 * $Id: Event.java,v 1.3 2003/08/17 01:32:22 tanderson Exp $ 44 * 45 * Date Author Changes 46 * 07/27/00 jima Created 47 */ 48 package org.exolab.jms.events; 49 50 import java.io.Serializable; 51 52 53 /*** 54 * This class specifies the object that is used by the {@link EventManager}. 55 * It defines the event type, the event listener and the callback object. 56 * <p> 57 * The event type is an integral value that identifies the type of event to 58 * fire. It is transparent to the {@link EventManager}. 59 * <p> 60 * The event listener must implement the {@link EventHandler} interface. 61 * <p> 62 * The callback object must be {@link Serializable} and is passed back to the 63 * {@link EventHandler} when the event fires. 64 * <p> 65 * Most importantly this class is {@link Serializable} so that it can be 66 * stored, if required. 67 * 68 * @version $Revision: 1.3 $ $Date: 2003/08/17 01:32:22 $ 69 * @author <a href="mailto:jima@intalio.com">Jim Alateras</a> 70 */ 71 public class Event 72 implements Serializable { 73 74 /*** 75 * The event type. 76 */ 77 private int _eventType; 78 79 /*** 80 * The _eventHandler is the object that is notified when the event fires. 81 * It must be Serializable so that it can be persisted. 82 */ 83 private EventHandler _eventHandler = null; 84 85 /*** 86 * The _callbackObject is optionally specified and is passed back to the 87 * _eventHandler during notification. 88 */ 89 private Object _callbackObject = null; 90 91 92 /*** 93 * The constructor instantiates an instance of this class with the 94 * specified parameters. The event and listener must be non-null and 95 * valid but the callback object may be null. 96 * 97 * @param event the type of event to fire 98 * @param listener the object that will receive the event 99 * @param callback a callback object, that is Serializable 100 * @throws IllegalEventDefinedException 101 */ 102 public Event(int event, EventHandler listener, Object callback) 103 throws IllegalEventDefinedException { 104 if ((event != 0) && 105 (listener != null)) { 106 _eventType = event; 107 _eventHandler = listener; 108 109 // if the callback object has been specified then ensure that 110 // it is Serializabe. If the object isnot Serializable then throw 111 // an exception. 112 if (callback != null) { 113 if (callback instanceof Serializable) { 114 _callbackObject = callback; 115 } else { 116 throw new IllegalEventDefinedException( 117 "The callback object is not Serializable"); 118 } 119 } 120 } else { 121 // event not-well specified 122 throw new IllegalEventDefinedException( 123 "event is 0 or listener is null"); 124 } 125 } 126 127 /*** 128 * Return the event type. 129 * 130 * @return int 131 */ 132 public int getEventType() { 133 return _eventType; 134 } 135 136 /*** 137 * Return the event listener 138 * 139 * @return EventHandler 140 */ 141 public EventHandler getEventListener() { 142 return _eventHandler; 143 } 144 145 /*** 146 * Return a reference to the callbacl object. The returned object may be 147 * null 148 * 149 * @return Object 150 */ 151 public Object getCallbackObject() { 152 return _callbackObject; 153 } 154 } 155 156

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