001 /*
002 * Copyright 2003-2004 The Apache Software Foundation
003 *
004 * Licensed under the Apache License, Version 2.0 (the "License");
005 * you may not use this file except in compliance with the License.
006 * You may obtain a copy of the License at
007 *
008 * http://www.apache.org/licenses/LICENSE-2.0
009 *
010 * Unless required by applicable law or agreed to in writing, software
011 * distributed under the License is distributed on an "AS IS" BASIS,
012 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
013 * See the License for the specific language governing permissions and
014 * limitations under the License.
015 */
016 package org.apache.commons.events.observable;
017
018 import java.util.Collection;
019 import java.util.EventObject;
020
021 /**
022 * Base event class extended by each class that encapsulates event information.
023 * <p>
024 * This class can be used as is, but generally it is subclassed.
025 *
026 * @since Commons Events 1.0
027 * @version $Revision: 155443 $ $Date: 2005-02-26 13:19:51 +0000 (Sat, 26 Feb 2005) $
028 *
029 * @author Stephen Colebourne
030 */
031 public class ModificationEvent extends EventObject {
032
033 /** The source collection */
034 protected final ObservableCollection collection;
035 /** The handler */
036 protected final ModificationHandler handler;
037 /** The event code */
038 protected final int type;
039
040 // Constructor
041 //-----------------------------------------------------------------------
042 /**
043 * Constructor.
044 *
045 * @param obsCollection the event source
046 * @param handler the handler
047 * @param type the event type
048 */
049 public ModificationEvent(
050 final ObservableCollection obsCollection,
051 final ModificationHandler handler,
052 final int type) {
053
054 super(obsCollection);
055 this.collection = obsCollection;
056 this.handler = handler;
057 this.type = type;
058 }
059
060 // Basic info
061 //-----------------------------------------------------------------------
062 /**
063 * Gets the collection the event is reporting on.
064 * <p>
065 * Using this collection will bypass any decorators that have been added
066 * to the <code>ObservableCollection</code>. For example, if a synchronized
067 * decorator was added it will not be called by changes to this collection.
068 * <p>
069 * For the synchronization case, you are normally OK however. If you
070 * process the event in the same thread as the original change then your
071 * code will be protected by the original synchronized decorator and this
072 * collection may be used freely.
073 *
074 * @return the collection
075 */
076 public ObservableCollection getObservedCollection() {
077 return collection;
078 }
079
080 /**
081 * Gets the base collection underlying the observable collection.
082 * <p>
083 * Using this collection will bypass the event sending mechanism.
084 * It will also bypass any other decorators, such as synchronization.
085 * Use with care.
086 *
087 * @return the collection
088 */
089 public Collection getBaseCollection() {
090 return handler.getBaseCollection();
091 }
092
093 /**
094 * Gets the handler of the events.
095 *
096 * @return the handler
097 */
098 public ModificationHandler getHandler() {
099 return handler;
100 }
101
102 /**
103 * Gets the event type constant.
104 * <p>
105 * This is one of the <i>method</i> constants from {@link ModificationEventType}.
106 *
107 * @return the method event type constant
108 */
109 public int getType() {
110 return type;
111 }
112
113 // toString
114 //-----------------------------------------------------------------------
115 /**
116 * Gets a debugging string version of the event.
117 *
118 * @return a debugging string
119 */
120 public String toString() {
121 StringBuffer buf = new StringBuffer(64);
122 buf.append("ModificationEvent[type=");
123 buf.append(ModificationEventType.toString(type));
124 buf.append(']');
125 return buf.toString();
126 }
127
128 }