/* * Copyright (c) 2000, 2008, 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 java.util.*;import javax.swing.event.*;import java.io.Serializable;  /** * This class provides the ChangeListener part of the * SpinnerModel interface that should be suitable for most concrete SpinnerModel * implementations.  Subclasses must provide an implementation of the * <code>setValue</code>, <code>getValue</code>, <code>getNextValue</code> and * <code>getPreviousValue</code> methods. * * @see JSpinner * @see SpinnerModel * @see SpinnerListModel * @see SpinnerNumberModel * @see SpinnerDateModel * * @author Hans Muller * @since 1.4 */public abstract class AbstractSpinnerModel implements SpinnerModel, Serializable{     /**     * Only one ChangeEvent is needed per model instance since the     * event's only (read-only) state is the source property.  The source     * of events generated here is always "this".     */    private transient ChangeEvent changeEvent = null;      /**     * The list of ChangeListeners for this model.  Subclasses may     * store their own listeners here.     */    protected EventListenerList listenerList = new EventListenerList();      /**     * Adds a ChangeListener to the model's listener list.  The     * ChangeListeners must be notified when the models value changes.     *     * @param l the ChangeListener to add     * @see #removeChangeListener     * @see SpinnerModel#addChangeListener     */    public void addChangeListener(ChangeListener l) {        listenerList.add(ChangeListener.class, l);    }      /**     * Removes a ChangeListener from the model's listener list.     *     * @param l the ChangeListener to remove     * @see #addChangeListener     * @see SpinnerModel#removeChangeListener     */    public void removeChangeListener(ChangeListener l) {        listenerList.remove(ChangeListener.class, l);    }      /**     * Returns an array of all the <code>ChangeListener</code>s added     * to this AbstractSpinnerModel with addChangeListener().     *     * @return all of the <code>ChangeListener</code>s added or an empty     *         array if no listeners have been added     * @since 1.4     */    public ChangeListener[] getChangeListeners() {        return listenerList.getListeners(ChangeListener.class);    }      /**     * Run each ChangeListeners stateChanged() method.     *     * @see #setValue     * @see EventListenerList     */    protected void fireStateChanged()    {        Object[] listeners = listenerList.getListenerList();        for (int i = listeners.length - 2; i >= 0; i -=2 ) {            if (listeners[i] == ChangeListener.class) {                if (changeEvent == null) {                    changeEvent = new ChangeEvent(this);                }                ((ChangeListener)listeners[i+1]).stateChanged(changeEvent);            }        }    }      /**     * Return an array of all the listeners of the given type that     * were added to this model.  For example to find all of the     * ChangeListeners added to this model:     * <pre>     * myAbstractSpinnerModel.getListeners(ChangeListener.class);     * </pre>     *     * @param listenerType the type of listeners to return, e.g. ChangeListener.class     * @return all of the objects receiving <em>listenerType</em> notifications     *         from this model     */    public <T extends EventListener> T[] getListeners(Class<T> listenerType) {        return listenerList.getListeners(listenerType);    }}