AbstractCellEditor.java

/*
 * Copyright (c) 1999, 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
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package javax.swing;

import javax.swing.event.*;
import java.util.EventObject;
import java.io.Serializable;

/**
 *
 * A base class for <code>CellEditors</code>, providing default
 * implementations for the methods in the <code>CellEditor</code>
 * interface except <code>getCellEditorValue()</code>.
 * Like the other abstract implementations in Swing, also manages a list
 * of listeners.
 *
 * <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}.
 *
 * @author Philip Milne
 * @since 1.3
 */
@SuppressWarnings("serial") // Same-version serialization only
public abstract class AbstractCellEditor implements CellEditor, Serializable {

    /**
     * The list of listeners.
     */
    protected EventListenerList listenerList = new EventListenerList();
    /**
     * The change event.
     */
    protected transient ChangeEvent changeEvent = null;

    /**
     * Constructor for subclasses to call.
     */
    protected AbstractCellEditor() {}

    // Force this to be implemented.
    // public Object  getCellEditorValue()

    /**
     * Returns true.
     * @param e  an event object
     * @return true
     */
    public boolean isCellEditable(EventObject e) {
        return true;
    }

    /**
     * Returns true.
     * @param anEvent  an event object
     * @return true
     */
    public boolean shouldSelectCell(EventObject anEvent) {
        return true;
    }

    /**
     * Calls <code>fireEditingStopped</code> and returns true.
     * @return true
     */
    public boolean stopCellEditing() {
        fireEditingStopped();
        return true;
    }

    /**
     * Calls <code>fireEditingCanceled</code>.
     */
    public void  cancelCellEditing() {
        fireEditingCanceled();
    }

    /**
     * Adds a <code>CellEditorListener</code> to the listener list.
     * @param l  the new listener to be added
     */
    public void addCellEditorListener(CellEditorListener l) {
        listenerList.add(CellEditorListener.class, l);
    }

    /**
     * Removes a <code>CellEditorListener</code> from the listener list.
     * @param l  the listener to be removed
     */
    public void removeCellEditorListener(CellEditorListener l) {
        listenerList.remove(CellEditorListener.class, l);
    }

    /**
     * Returns an array of all the <code>CellEditorListener</code>s added
     * to this AbstractCellEditor with addCellEditorListener().
     *
     * @return all of the <code>CellEditorListener</code>s added or an empty
     *         array if no listeners have been added
     * @since 1.4
     */
    public CellEditorListener[] getCellEditorListeners() {
        return listenerList.getListeners(CellEditorListener.class);
    }

    /**
     * Notifies all listeners that have registered interest for
     * notification on this event type.  The event instance
     * is created lazily.
     *
     * @see EventListenerList
     */
    protected void fireEditingStopped() {
        // Guaranteed to return a non-null array
        Object[] listeners = listenerList.getListenerList();
        // Process the listeners last to first, notifying
        // those that are interested in this event
        for (int i = listeners.length-2; i>=0; i-=2) {
            if (listeners[i]==CellEditorListener.class) {
                // Lazily create the event:
                if (changeEvent == null)
                    changeEvent = new ChangeEvent(this);
                ((CellEditorListener)listeners[i+1]).editingStopped(changeEvent);
            }
        }
    }

    /**
     * Notifies all listeners that have registered interest for
     * notification on this event type.  The event instance
     * is created lazily.
     *
     * @see EventListenerList
     */
    protected void fireEditingCanceled() {
        // Guaranteed to return a non-null array
        Object[] listeners = listenerList.getListenerList();
        // Process the listeners last to first, notifying
        // those that are interested in this event
        for (int i = listeners.length-2; i>=0; i-=2) {
            if (listeners[i]==CellEditorListener.class) {
                // Lazily create the event:
                if (changeEvent == null)
                    changeEvent = new ChangeEvent(this);
                ((CellEditorListener)listeners[i+1]).editingCanceled(changeEvent);
            }
        }
    }
}