Java tutorial
/* * Copyright (c) 1997, 2015, Oracle and/or its affiliates. All rights reserved. * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER. * * This code is free software; you can redistribute it and/or modify it * under the terms of the GNU General Public License version 2 only, as * published by the Free Software Foundation. Oracle designates this * particular file as subject to the "Classpath" exception as provided * by Oracle in the LICENSE file that accompanied this code. * * This code is distributed in the hope that it will be useful, but WITHOUT * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License * version 2 for more details (a copy is included in the LICENSE file that * accompanied this code). * * You should have received a copy of the GNU General Public License version * 2 along with this work; if not, write to the Free Software Foundation, * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA. * * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA * or visit www.oracle.com if you need additional information or have any * questions. */ package javax.swing; import javax.swing.event.*; import java.io.Serializable; import java.util.EventListener; /** * The abstract definition for the data model that provides * a <code>List</code> with its contents. * <p> * <strong>Warning:</strong> * Serialized objects of this class will not be compatible with * future Swing releases. The current serialization support is * appropriate for short term storage or RMI between applications running * the same version of Swing. As of 1.4, support for long term storage * of all JavaBeans™ * has been added to the <code>java.beans</code> package. * Please see {@link java.beans.XMLEncoder}. * * @param <E> the type of the elements of this model * * @author Hans Muller * @since 1.2 */ @SuppressWarnings("serial") // Same-version serialization only public abstract class AbstractListModel<E> implements ListModel<E>, Serializable { /** * The listener list. */ protected EventListenerList listenerList = new EventListenerList(); /** * Adds a listener to the list that's notified each time a change * to the data model occurs. * * @param l the <code>ListDataListener</code> to be added */ public void addListDataListener(ListDataListener l) { listenerList.add(ListDataListener.class, l); } /** * Removes a listener from the list that's notified each time a * change to the data model occurs. * * @param l the <code>ListDataListener</code> to be removed */ public void removeListDataListener(ListDataListener l) { listenerList.remove(ListDataListener.class, l); } /** * Returns an array of all the list data listeners * registered on this <code>AbstractListModel</code>. * * @return all of this model's <code>ListDataListener</code>s, * or an empty array if no list data listeners * are currently registered * * @see #addListDataListener * @see #removeListDataListener * * @since 1.4 */ public ListDataListener[] getListDataListeners() { return listenerList.getListeners(ListDataListener.class); } /** * <code>AbstractListModel</code> subclasses must call this method * <b>after</b> * one or more elements of the list change. The changed elements * are specified by the closed interval index0, index1 -- the endpoints * are included. Note that * index0 need not be less than or equal to index1. * * @param source the <code>ListModel</code> that changed, typically "this" * @param index0 one end of the new interval * @param index1 the other end of the new interval * @see EventListenerList * @see DefaultListModel */ protected void fireContentsChanged(Object source, int index0, int index1) { Object[] listeners = listenerList.getListenerList(); ListDataEvent e = null; for (int i = listeners.length - 2; i >= 0; i -= 2) { if (listeners[i] == ListDataListener.class) { if (e == null) { e = new ListDataEvent(source, ListDataEvent.CONTENTS_CHANGED, index0, index1); } ((ListDataListener) listeners[i + 1]).contentsChanged(e); } } } /** * <code>AbstractListModel</code> subclasses must call this method * <b>after</b> * one or more elements are added to the model. The new elements * are specified by a closed interval index0, index1 -- the enpoints * are included. Note that * index0 need not be less than or equal to index1. * * @param source the <code>ListModel</code> that changed, typically "this" * @param index0 one end of the new interval * @param index1 the other end of the new interval * @see EventListenerList * @see DefaultListModel */ protected void fireIntervalAdded(Object source, int index0, int index1) { Object[] listeners = listenerList.getListenerList(); ListDataEvent e = null; for (int i = listeners.length - 2; i >= 0; i -= 2) { if (listeners[i] == ListDataListener.class) { if (e == null) { e = new ListDataEvent(source, ListDataEvent.INTERVAL_ADDED, index0, index1); } ((ListDataListener) listeners[i + 1]).intervalAdded(e); } } } /** * <code>AbstractListModel</code> subclasses must call this method * <b>after</b> one or more elements are removed from the model. * <code>index0</code> and <code>index1</code> are the end points * of the interval that's been removed. Note that <code>index0</code> * need not be less than or equal to <code>index1</code>. * * @param source the <code>ListModel</code> that changed, typically "this" * @param index0 one end of the removed interval, * including <code>index0</code> * @param index1 the other end of the removed interval, * including <code>index1</code> * @see EventListenerList * @see DefaultListModel */ protected void fireIntervalRemoved(Object source, int index0, int index1) { Object[] listeners = listenerList.getListenerList(); ListDataEvent e = null; for (int i = listeners.length - 2; i >= 0; i -= 2) { if (listeners[i] == ListDataListener.class) { if (e == null) { e = new ListDataEvent(source, ListDataEvent.INTERVAL_REMOVED, index0, index1); } ((ListDataListener) listeners[i + 1]).intervalRemoved(e); } } } /** * Returns an array of all the objects currently registered as * <code><em>Foo</em>Listener</code>s * upon this model. * <code><em>Foo</em>Listener</code>s * are registered using the <code>add<em>Foo</em>Listener</code> method. * <p> * You can specify the <code>listenerType</code> argument * with a class literal, such as <code><em>Foo</em>Listener.class</code>. * For example, you can query a list model * <code>m</code> * for its list data listeners * with the following code: * * <pre>ListDataListener[] ldls = (ListDataListener[])(m.getListeners(ListDataListener.class));</pre> * * If no such listeners exist, * this method returns an empty array. * * @param <T> the type of {@code EventListener} class being requested * @param listenerType the type of listeners requested; * this parameter should specify an interface * that descends from <code>java.util.EventListener</code> * @return an array of all objects registered as * <code><em>Foo</em>Listener</code>s * on this model, * or an empty array if no such * listeners have been added * @exception ClassCastException if <code>listenerType</code> doesn't * specify a class or interface that implements * <code>java.util.EventListener</code> * * @see #getListDataListeners * * @since 1.3 */ public <T extends EventListener> T[] getListeners(Class<T> listenerType) { return listenerList.getListeners(listenerType); } }