1 /*
2 * Copyright (c) 1997, 2014, Oracle and/or its affiliates. All rights reserved.
3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
4 *
5 * This code is free software; you can redistribute it and/or modify it
6 * under the terms of the GNU General Public License version 2 only, as
7 * published by the Free Software Foundation. Oracle designates this
8 * particular file as subject to the "Classpath" exception as provided
9 * by Oracle in the LICENSE file that accompanied this code.
10 *
11 * This code is distributed in the hope that it will be useful, but WITHOUT
12 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
13 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
14 * version 2 for more details (a copy is included in the LICENSE file that
15 * accompanied this code).
16 *
17 * You should have received a copy of the GNU General Public License version
18 * 2 along with this work; if not, write to the Free Software Foundation,
19 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
20 *
21 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
22 * or visit www.oracle.com if you need additional information or have any
23 * questions.
24 */
25
26 package javax.swing;
27
28 import javax.swing.event.*;
29 import java.io.Serializable;
30 import java.util.EventListener;
31
32 /**
33 * The abstract definition for the data model that provides
34 * a <code>List</code> with its contents.
35 * <p>
36 * <strong>Warning:</strong>
37 * Serialized objects of this class will not be compatible with
38 * future Swing releases. The current serialization support is
39 * appropriate for short term storage or RMI between applications running
40 * the same version of Swing. As of 1.4, support for long term storage
41 * of all JavaBeans™
42 * has been added to the <code>java.beans</code> package.
43 * Please see {@link java.beans.XMLEncoder}.
44 *
45 * @param <E> the type of the elements of this model
46 *
47 * @author Hans Muller
48 * @since 1.2
49 */
50 @SuppressWarnings("serial") // Same-version serialization only
51 public abstract class AbstractListModel<E> implements ListModel<E>, Serializable
52 {
53 protected EventListenerList listenerList = new EventListenerList();
54
55
56 /**
57 * Adds a listener to the list that's notified each time a change
58 * to the data model occurs.
59 *
60 * @param l the <code>ListDataListener</code> to be added
61 */
62 public void addListDataListener(ListDataListener l) {
63 listenerList.add(ListDataListener.class, l);
64 }
65
66
67 /**
68 * Removes a listener from the list that's notified each time a
69 * change to the data model occurs.
70 *
71 * @param l the <code>ListDataListener</code> to be removed
72 */
73 public void removeListDataListener(ListDataListener l) {
74 listenerList.remove(ListDataListener.class, l);
75 }
76
77
78 /**
79 * Returns an array of all the list data listeners
80 * registered on this <code>AbstractListModel</code>.
81 *
82 * @return all of this model's <code>ListDataListener</code>s,
83 * or an empty array if no list data listeners
84 * are currently registered
85 *
86 * @see #addListDataListener
87 * @see #removeListDataListener
88 *
89 * @since 1.4
90 */
91 public ListDataListener[] getListDataListeners() {
92 return listenerList.getListeners(ListDataListener.class);
93 }
94
95
96 /**
97 * <code>AbstractListModel</code> subclasses must call this method
98 * <b>after</b>
99 * one or more elements of the list change. The changed elements
100 * are specified by the closed interval index0, index1 -- the endpoints
101 * are included. Note that
102 * index0 need not be less than or equal to index1.
103 *
104 * @param source the <code>ListModel</code> that changed, typically "this"
105 * @param index0 one end of the new interval
106 * @param index1 the other end of the new interval
107 * @see EventListenerList
108 * @see DefaultListModel
109 */
110 protected void fireContentsChanged(Object source, int index0, int index1)
111 {
112 Object[] listeners = listenerList.getListenerList();
113 ListDataEvent e = null;
114
115 for (int i = listeners.length - 2; i >= 0; i -= 2) {
116 if (listeners[i] == ListDataListener.class) {
117 if (e == null) {
118 e = new ListDataEvent(source, ListDataEvent.CONTENTS_CHANGED, index0, index1);
119 }
120 ((ListDataListener)listeners[i+1]).contentsChanged(e);
121 }
122 }
123 }
124
125
126 /**
127 * <code>AbstractListModel</code> subclasses must call this method
128 * <b>after</b>
129 * one or more elements are added to the model. The new elements
130 * are specified by a closed interval index0, index1 -- the enpoints
131 * are included. Note that
132 * index0 need not be less than or equal to index1.
133 *
134 * @param source the <code>ListModel</code> that changed, typically "this"
135 * @param index0 one end of the new interval
136 * @param index1 the other end of the new interval
137 * @see EventListenerList
138 * @see DefaultListModel
139 */
140 protected void fireIntervalAdded(Object source, int index0, int index1)
141 {
142 Object[] listeners = listenerList.getListenerList();
143 ListDataEvent e = null;
144
145 for (int i = listeners.length - 2; i >= 0; i -= 2) {
146 if (listeners[i] == ListDataListener.class) {
147 if (e == null) {
148 e = new ListDataEvent(source, ListDataEvent.INTERVAL_ADDED, index0, index1);
149 }
150 ((ListDataListener)listeners[i+1]).intervalAdded(e);
151 }
152 }
153 }
154
155
156 /**
157 * <code>AbstractListModel</code> subclasses must call this method
158 * <b>after</b> one or more elements are removed from the model.
159 * <code>index0</code> and <code>index1</code> are the end points
160 * of the interval that's been removed. Note that <code>index0</code>
161 * need not be less than or equal to <code>index1</code>.
162 *
163 * @param source the <code>ListModel</code> that changed, typically "this"
164 * @param index0 one end of the removed interval,
165 * including <code>index0</code>
166 * @param index1 the other end of the removed interval,
167 * including <code>index1</code>
168 * @see EventListenerList
169 * @see DefaultListModel
170 */
171 protected void fireIntervalRemoved(Object source, int index0, int index1)
172 {
173 Object[] listeners = listenerList.getListenerList();
174 ListDataEvent e = null;
175
176 for (int i = listeners.length - 2; i >= 0; i -= 2) {
177 if (listeners[i] == ListDataListener.class) {
178 if (e == null) {
179 e = new ListDataEvent(source, ListDataEvent.INTERVAL_REMOVED, index0, index1);
180 }
181 ((ListDataListener)listeners[i+1]).intervalRemoved(e);
182 }
183 }
184 }
185
186 /**
187 * Returns an array of all the objects currently registered as
188 * <code><em>Foo</em>Listener</code>s
189 * upon this model.
190 * <code><em>Foo</em>Listener</code>s
191 * are registered using the <code>add<em>Foo</em>Listener</code> method.
192 * <p>
193 * You can specify the <code>listenerType</code> argument
194 * with a class literal, such as <code><em>Foo</em>Listener.class</code>.
195 * For example, you can query a list model
196 * <code>m</code>
197 * for its list data listeners
198 * with the following code:
199 *
200 * <pre>ListDataListener[] ldls = (ListDataListener[])(m.getListeners(ListDataListener.class));</pre>
201 *
202 * If no such listeners exist,
203 * this method returns an empty array.
204 *
205 * @param <T> the type of {@code EventListener} class being requested
206 * @param listenerType the type of listeners requested;
207 * this parameter should specify an interface
208 * that descends from <code>java.util.EventListener</code>
209 * @return an array of all objects registered as
210 * <code><em>Foo</em>Listener</code>s
211 * on this model,
212 * or an empty array if no such
213 * listeners have been added
214 * @exception ClassCastException if <code>listenerType</code> doesn't
215 * specify a class or interface that implements
216 * <code>java.util.EventListener</code>
217 *
218 * @see #getListDataListeners
219 *
220 * @since 1.3
221 */
222 public <T extends EventListener> T[] getListeners(Class<T> listenerType) {
223 return listenerList.getListeners(listenerType);
224 }
225 }