/* * Copyright (c) 1997, 2007, 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.beans.ConstructorProperties; import java.awt.*;import java.awt.event.*;import java.awt.image.*; import javax.swing.plaf.*;import javax.swing.event.*;import javax.accessibility.*; import java.io.ObjectOutputStream;import java.io.ObjectInputStream;import java.io.IOException;  /** * An implementation of a "push" button.  * <p> * Buttons can be configured, and to some degree controlled, by * <code><a href="Action.html">Action</a></code>s.  Using an * <code>Action</code> with a button has many benefits beyond directly * configuring a button.  Refer to <a href="Action.html#buttonActions"> * Swing Components Supporting <code>Action</code></a> for more * details, and you can find more information in <a * href="http://java.sun.com/docs/books/tutorial/uiswing/misc/action.html">How * to Use Actions</a>, a section in <em>The Java Tutorial</em>. * <p> * See <a href="http://java.sun.com/docs/books/tutorial/uiswing/components/button.html">How to Use Buttons, Check Boxes, and Radio Buttons</a> * in <em>The Java Tutorial</em> * for information and examples of using buttons. * <p> * <strong>Warning:</strong> Swing is not thread safe. For more * information see <a * href="package-summary.html#threading">Swing's Threading * Policy</a>. * <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<sup><font size="-2">TM</font></sup> * has been added to the <code>java.beans</code> package. * Please see {@link java.beans.XMLEncoder}. * * @beaninfo *   attribute: isContainer false * description: An implementation of a \"push\" button. * * @author Jeff Dinkins */public class JButton extends AbstractButton implements Accessible {     /**     * @see #getUIClassID     * @see #readObject     */    private static final String uiClassID = "ButtonUI";     /**     * Creates a button with no set text or icon.     */    public JButton() {        this(null, null);    }     /**     * Creates a button with an icon.     *     * @param icon  the Icon image to display on the button     */    public JButton(Icon icon) {        this(null, icon);    }     /**     * Creates a button with text.     *     * @param text  the text of the button     */    @ConstructorProperties({"text"})    public JButton(String text) {        this(text, null);    }     /**     * Creates a button where properties are taken from the     * <code>Action</code> supplied.     *     * @param a the <code>Action</code> used to specify the new button     *     * @since 1.3     */    public JButton(Action a) {        this();        setAction(a);    }     /**     * Creates a button with initial text and an icon.     *     * @param text  the text of the button     * @param icon  the Icon image to display on the button     */    public JButton(String text, Icon icon) {        // Create the model        setModel(new DefaultButtonModel());         // initialize        init(text, icon);    }     /**     * Resets the UI property to a value from the current look and     * feel.     *     * @see JComponent#updateUI     */    public void updateUI() {        setUI((ButtonUI)UIManager.getUI(this));    }      /**     * Returns a string that specifies the name of the L&F class     * that renders this component.     *     * @return the string "ButtonUI"     * @see JComponent#getUIClassID     * @see UIDefaults#getUI     * @beaninfo     *        expert: true     *   description: A string that specifies the name of the L&F class.     */    public String getUIClassID() {        return uiClassID;    }      /**     * Gets the value of the <code>defaultButton</code> property,     * which if <code>true</code> means that this button is the current     * default button for its <code>JRootPane</code>.     * Most look and feels render the default button     * differently, and may potentially provide bindings     * to access the default button.     *     * @return the value of the <code>defaultButton</code> property     * @see JRootPane#setDefaultButton     * @see #isDefaultCapable     * @beaninfo     *  description: Whether or not this button is the default button     */    public boolean isDefaultButton() {        JRootPane root = SwingUtilities.getRootPane(this);        if (root != null) {            return root.getDefaultButton() == this;        }        return false;    }     /**     * Gets the value of the <code>defaultCapable</code> property.     *     * @return the value of the <code>defaultCapable</code> property     * @see #setDefaultCapable     * @see #isDefaultButton     * @see JRootPane#setDefaultButton     */    public boolean isDefaultCapable() {        return defaultCapable;    }     /**     * Sets the <code>defaultCapable</code> property,     * which determines whether this button can be     * made the default button for its root pane.     * The default value of the <code>defaultCapable</code>     * property is <code>true</code> unless otherwise     * specified by the look and feel.     *     * @param defaultCapable <code>true</code> if this button will be     *        capable of being the default button on the     *        <code>RootPane</code>; otherwise <code>false</code>     * @see #isDefaultCapable     * @beaninfo     *        bound: true     *    attribute: visualUpdate true     *  description: Whether or not this button can be the default button     */    public void setDefaultCapable(boolean defaultCapable) {        boolean oldDefaultCapable = this.defaultCapable;        this.defaultCapable = defaultCapable;        firePropertyChange("defaultCapable", oldDefaultCapable, defaultCapable);    }     /**     * Overrides <code>JComponent.removeNotify</code> to check if     * this button is currently set as the default button on the     * <code>RootPane</code>, and if so, sets the <code>RootPane</code>'s     * default button to <code>null</code> to ensure the     * <code>RootPane</code> doesn't hold onto an invalid button reference.     */    public void removeNotify() {        JRootPane root = SwingUtilities.getRootPane(this);        if (root != null && root.getDefaultButton() == this) {            root.setDefaultButton(null);        }        super.removeNotify();    }     /**     * See readObject() and writeObject() in JComponent for more     * information about serialization in Swing.     */    private void writeObject(ObjectOutputStream s) throws IOException {        s.defaultWriteObject();        if (getUIClassID().equals(uiClassID)) {            byte count = JComponent.getWriteObjCounter(this);            JComponent.setWriteObjCounter(this, --count);            if (count == 0 && ui != null) {                ui.installUI(this);            }        }    }      /**     * Returns a string representation of this <code>JButton</code>.     * This method is intended to be used only for debugging purposes, and the     * content and format of the returned string may vary between     * implementations. The returned string may be empty but may not     * be <code>null</code>.     *     * @return  a string representation of this <code>JButton</code>     */    protected String paramString() {        String defaultCapableString = (defaultCapable ? "true" : "false");         return super.paramString() +            ",defaultCapable=" + defaultCapableString;    }  /////////////////// Accessibility support////////////////     /**     * Gets the <code>AccessibleContext</code> associated with this     * <code>JButton</code>. For <code>JButton</code>s,     * the <code>AccessibleContext</code> takes the form of an     * <code>AccessibleJButton</code>.     * A new <code>AccessibleJButton</code> instance is created if necessary.     *     * @return an <code>AccessibleJButton</code> that serves as the     *         <code>AccessibleContext</code> of this <code>JButton</code>     * @beaninfo     *       expert: true     *  description: The AccessibleContext associated with this Button.     */    public AccessibleContext getAccessibleContext() {        if (accessibleContext == null) {            accessibleContext = new AccessibleJButton();        }        return accessibleContext;    }     /**     * This class implements accessibility support for the     * <code>JButton</code> class.  It provides an implementation of the     * Java Accessibility API appropriate to button user-interface     * elements.     * <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<sup><font size="-2">TM</font></sup>     * has been added to the <code>java.beans</code> package.     * Please see {@link java.beans.XMLEncoder}.     */    protected class AccessibleJButton extends AccessibleAbstractButton {         /**         * Get the role of this object.         *         * @return an instance of AccessibleRole describing the role of the         * object         * @see AccessibleRole         */        public AccessibleRole getAccessibleRole() {            return AccessibleRole.PUSH_BUTTON;        }    } // inner class AccessibleJButton}