1 /*
2 * Copyright (c) 1997, 2015, 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 /**
54 * The listener list.
55 */
56 protected EventListenerList listenerList = new EventListenerList();
57
58
59 /**
60 * Adds a listener to the list that's notified each time a change
61 * to the data model occurs.
62 *
63 * @param l the <code>ListDataListener</code> to be added
64 */
65 public void addListDataListener(ListDataListener l) {
66 listenerList.add(ListDataListener.class, l);
67 }
68
69
70 /**
71 * Removes a listener from the list that's notified each time a
72 * change to the data model occurs.
73 *
74 * @param l the <code>ListDataListener</code> to be removed
75 */
76 public void removeListDataListener(ListDataListener l) {
77 listenerList.remove(ListDataListener.class, l);
78 }
79
80
81 /**
82 * Returns an array of all the list data listeners
83 * registered on this <code>AbstractListModel</code>.
84 *
85 * @return all of this model's <code>ListDataListener</code>s,
86 * or an empty array if no list data listeners
87 * are currently registered
88 *
89 * @see #addListDataListener
90 * @see #removeListDataListener
91 *
92 * @since 1.4
93 */
94 public ListDataListener[] getListDataListeners() {
95 return listenerList.getListeners(ListDataListener.class);
96 }
97
98
99 /**
100 * <code>AbstractListModel</code> subclasses must call this method
101 * <b>after</b>
102 * one or more elements of the list change. The changed elements
103 * are specified by the closed interval index0, index1 -- the endpoints
104 * are included. Note that
105 * index0 need not be less than or equal to index1.
106 *
107 * @param source the <code>ListModel</code> that changed, typically "this"
108 * @param index0 one end of the new interval
109 * @param index1 the other end of the new interval
110 * @see EventListenerList
111 * @see DefaultListModel
112 */
113 protected void fireContentsChanged(Object source, int index0, int index1)
114 {
115 Object[] listeners = listenerList.getListenerList();
116 ListDataEvent e = null;
117
118 for (int i = listeners.length - 2; i >= 0; i -= 2) {
119 if (listeners[i] == ListDataListener.class) {
120 if (e == null) {
121 e = new ListDataEvent(source, ListDataEvent.CONTENTS_CHANGED, index0, index1);
122 }
123 ((ListDataListener)listeners[i+1]).contentsChanged(e);
124 }
125 }
126 }
127
128
129 /**
130 * <code>AbstractListModel</code> subclasses must call this method
131 * <b>after</b>
132 * one or more elements are added to the model. The new elements
133 * are specified by a closed interval index0, index1 -- the enpoints
134 * are included. Note that
135 * index0 need not be less than or equal to index1.
136 *
137 * @param source the <code>ListModel</code> that changed, typically "this"
138 * @param index0 one end of the new interval
139 * @param index1 the other end of the new interval
140 * @see EventListenerList
141 * @see DefaultListModel
142 */
143 protected void fireIntervalAdded(Object source, int index0, int index1)
144 {
145 Object[] listeners = listenerList.getListenerList();
146 ListDataEvent e = null;
147
148 for (int i = listeners.length - 2; i >= 0; i -= 2) {
149 if (listeners[i] == ListDataListener.class) {
150 if (e == null) {
151 e = new ListDataEvent(source, ListDataEvent.INTERVAL_ADDED, index0, index1);
152 }
153 ((ListDataListener)listeners[i+1]).intervalAdded(e);
154 }
155 }
156 }
157
158
159 /**
160 * <code>AbstractListModel</code> subclasses must call this method
161 * <b>after</b> one or more elements are removed from the model.
162 * <code>index0</code> and <code>index1</code> are the end points
163 * of the interval that's been removed. Note that <code>index0</code>
164 * need not be less than or equal to <code>index1</code>.
165 *
166 * @param source the <code>ListModel</code> that changed, typically "this"
167 * @param index0 one end of the removed interval,
168 * including <code>index0</code>
169 * @param index1 the other end of the removed interval,
170 * including <code>index1</code>
171 * @see EventListenerList
172 * @see DefaultListModel
173 */
174 protected void fireIntervalRemoved(Object source, int index0, int index1)
175 {
176 Object[] listeners = listenerList.getListenerList();
177 ListDataEvent e = null;
178
179 for (int i = listeners.length - 2; i >= 0; i -= 2) {
180 if (listeners[i] == ListDataListener.class) {
181 if (e == null) {
182 e = new ListDataEvent(source, ListDataEvent.INTERVAL_REMOVED, index0, index1);
183 }
184 ((ListDataListener)listeners[i+1]).intervalRemoved(e);
185 }
186 }
187 }
188
189 /**
190 * Returns an array of all the objects currently registered as
191 * <code><em>Foo</em>Listener</code>s
192 * upon this model.
193 * <code><em>Foo</em>Listener</code>s
194 * are registered using the <code>add<em>Foo</em>Listener</code> method.
195 * <p>
196 * You can specify the <code>listenerType</code> argument
197 * with a class literal, such as <code><em>Foo</em>Listener.class</code>.
198 * For example, you can query a list model
199 * <code>m</code>
200 * for its list data listeners
201 * with the following code:
202 *
203 * <pre>ListDataListener[] ldls = (ListDataListener[])(m.getListeners(ListDataListener.class));</pre>
204 *
205 * If no such listeners exist,
206 * this method returns an empty array.
207 *
208 * @param <T> the type of {@code EventListener} class being requested
209 * @param listenerType the type of listeners requested;
210 * this parameter should specify an interface
211 * that descends from <code>java.util.EventListener</code>
212 * @return an array of all objects registered as
213 * <code><em>Foo</em>Listener</code>s
214 * on this model,
215 * or an empty array if no such
216 * listeners have been added
217 * @exception ClassCastException if <code>listenerType</code> doesn't
218 * specify a class or interface that implements
219 * <code>java.util.EventListener</code>
220 *
221 * @see #getListDataListeners
222 *
223 * @since 1.3
224 */
225 public <T extends EventListener> T[] getListeners(Class<T> listenerType) {
226 return listenerList.getListeners(listenerType);
227 }
228 }