1 /*
2 * Copyright (c) 1997, 2018, 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.EventListenerList;
29 import javax.swing.event.ListDataListener;
30 import javax.swing.event.ListDataEvent;
31 import java.io.Serializable;
32 import java.util.function.BiConsumer;
33 import java.util.EventListener;
34
35 /**
36 * The abstract definition for the data model that provides
37 * a <code>List</code> with its contents.
38 * <p>
39 * <strong>Warning:</strong>
40 * Serialized objects of this class will not be compatible with
41 * future Swing releases. The current serialization support is
42 * appropriate for short term storage or RMI between applications running
43 * the same version of Swing. As of 1.4, support for long term storage
44 * of all JavaBeans™
45 * has been added to the <code>java.beans</code> package.
46 * Please see {@link java.beans.XMLEncoder}.
47 *
48 * @param <E> the type of the elements of this model
49 *
50 * @author Hans Muller
51 * @since 1.2
52 */
53 @SuppressWarnings("serial") // Same-version serialization only
54 public abstract class AbstractListModel<E> implements ListModel<E>, Serializable
55 {
56 /**
57 * The listener list.
58 */
59 protected EventListenerList listenerList = new EventListenerList();
60
61
62 /**
63 * Adds a listener to the list that's notified each time a change
64 * to the data model occurs.
65 *
66 * @param l the <code>ListDataListener</code> to be added
67 */
68 public void addListDataListener(ListDataListener l) {
69 listenerList.add(ListDataListener.class, l);
70 }
71
72
73 /**
74 * Removes a listener from the list that's notified each time a
75 * change to the data model occurs.
76 *
77 * @param l the <code>ListDataListener</code> to be removed
78 */
79 public void removeListDataListener(ListDataListener l) {
80 listenerList.remove(ListDataListener.class, l);
81 }
82
83
84 /**
85 * Returns an array of all the list data listeners
86 * registered on this <code>AbstractListModel</code>.
87 *
88 * @return all of this model's <code>ListDataListener</code>s,
89 * or an empty array if no list data listeners
90 * are currently registered
91 *
92 * @see #addListDataListener
93 * @see #removeListDataListener
94 *
95 * @since 1.4
96 */
97 public ListDataListener[] getListDataListeners() {
98 return listenerList.getListeners(ListDataListener.class);
99 }
100
101
102 /**
103 * The workhorse function which does the job of calling the listeners
104 * interested in listening to the appropriate event that has occurred.
105 * Functions fireContentsChanged, fireIntervalAdded and fireIntervalRemoved
106 * call this function with appropriate arguments filled.
107 */
108 private void fireUpdates(Object source, int index0, int index1, int eventType,
109 BiConsumer<ListDataListener, ListDataEvent> func) {
110 Object[] listeners = listenerList.getListenerList();
111 ListDataEvent e = null;
112
113 for (int i = listeners.length - 2; i >= 0; i -= 2) {
114 if (listeners[i] == ListDataListener.class) {
115 if (e == null) {
116 e = new ListDataEvent(source, eventType, index0, index1);
117 }
118 func.accept((ListDataListener)listeners[i+1], e);
119 }
120 }
121 }
122
123
124 /**
125 * <code>AbstractListModel</code> subclasses must call this method
126 * <b>after</b>
127 * one or more elements of the list change. The changed elements
128 * are specified by the closed interval index0, index1 -- the endpoints
129 * are included. Note that
130 * index0 need not be less than or equal to index1.
131 *
132 * @param source the <code>ListModel</code> that changed, typically "this"
133 * @param index0 one end of the new interval
134 * @param index1 the other end of the new interval
135 * @see EventListenerList
136 * @see DefaultListModel
137 */
138 protected void fireContentsChanged(Object source, int index0, int index1)
139 {
140 fireUpdates(source, index0, index1, ListDataEvent.CONTENTS_CHANGED,
141 (l, e) -> l.contentsChanged(e));
142 }
143
144
145 /**
146 * <code>AbstractListModel</code> subclasses must call this method
147 * <b>after</b>
148 * one or more elements are added to the model. The new elements
149 * are specified by a closed interval index0, index1 -- the enpoints
150 * are included. Note that
151 * index0 need not be less than or equal to index1.
152 *
153 * @param source the <code>ListModel</code> that changed, typically "this"
154 * @param index0 one end of the new interval
155 * @param index1 the other end of the new interval
156 * @see EventListenerList
157 * @see DefaultListModel
158 */
159 protected void fireIntervalAdded(Object source, int index0, int index1)
160 {
161 fireUpdates(source, index0, index1, ListDataEvent.INTERVAL_ADDED,
162 (l, e) -> l.intervalAdded(e));
163 }
164
165
166 /**
167 * <code>AbstractListModel</code> subclasses must call this method
168 * <b>after</b> one or more elements are removed from the model.
169 * <code>index0</code> and <code>index1</code> are the end points
170 * of the interval that's been removed. Note that <code>index0</code>
171 * need not be less than or equal to <code>index1</code>.
172 *
173 * @param source the <code>ListModel</code> that changed, typically "this"
174 * @param index0 one end of the removed interval,
175 * including <code>index0</code>
176 * @param index1 the other end of the removed interval,
177 * including <code>index1</code>
178 * @see EventListenerList
179 * @see DefaultListModel
180 */
181 protected void fireIntervalRemoved(Object source, int index0, int index1)
182 {
183 fireUpdates(source, index0, index1, ListDataEvent.INTERVAL_REMOVED,
184 (l, e) -> l.intervalRemoved(e));
185 }
186
187 /**
188 * Returns an array of all the objects currently registered as
189 * <code><em>Foo</em>Listener</code>s
190 * upon this model.
191 * <code><em>Foo</em>Listener</code>s
192 * are registered using the <code>add<em>Foo</em>Listener</code> method.
193 * <p>
194 * You can specify the <code>listenerType</code> argument
195 * with a class literal, such as <code><em>Foo</em>Listener.class</code>.
196 * For example, you can query a list model
197 * <code>m</code>
198 * for its list data listeners
199 * with the following code:
200 *
201 * <pre>ListDataListener[] ldls = (ListDataListener[])(m.getListeners(ListDataListener.class));</pre>
202 *
203 * If no such listeners exist,
204 * this method returns an empty array.
205 *
206 * @param <T> the type of {@code EventListener} class being requested
207 * @param listenerType the type of listeners requested;
208 * this parameter should specify an interface
209 * that descends from <code>java.util.EventListener</code>
210 * @return an array of all objects registered as
211 * <code><em>Foo</em>Listener</code>s
212 * on this model,
213 * or an empty array if no such
214 * listeners have been added
215 * @exception ClassCastException if <code>listenerType</code> doesn't
216 * specify a class or interface that implements
217 * <code>java.util.EventListener</code>
218 *
219 * @see #getListDataListeners
220 *
221 * @since 1.3
222 */
223 public <T extends EventListener> T[] getListeners(Class<T> listenerType) {
224 return listenerList.getListeners(listenerType);
225 }
226 }