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/*
 * 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
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package javax.swing;

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.


Buttons can be configured, and to some degree controlled, by
Actions.  Using an
Action with a button has many benefits beyond directly
configuring a button.  Refer to 
Swing Components Supporting Action for more
details, and you can find more information in How
to Use Actions, a section in The Java Tutorial.


See How to Use Buttons, Check Boxes, and Radio Buttons
in The Java Tutorial
for information and examples of using buttons.


Warning: Swing is not thread safe. For more
information see Swing's Threading
Policy.


Warning:
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 JavaBeansTM
has been added to the java.beans package. Please see XMLEncoder. 
Author:Jeff Dinkins
@beaninfo
  attribute: isContainer false
description: An implementation of a \"push\" button.
/**
 * 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 Also:
/**
     * @see #getUIClassID
     * @see #readObject
     */
    private static final String uiClassID = "ButtonUI";

    
Creates a button with no set text or icon.

/**
     * Creates a button with no set text or icon.
     */
    public JButton() {
        this(null, null);
    }

    
Creates a button with an icon.

Params:
  • icon –  the Icon image to display on the button
/**
     * 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.

Params:
  • text –  the text of the button
/**
     * Creates a button with text.
     *
     * @param text  the text of the button
     */
    public JButton(String text) {
        this(text, null);
    }

    
Creates a button where properties are taken from the
Action supplied.

Params:
  • a – the Action used to specify the new button
Since:1.3
/**
     * 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.

Params:
  • text –  the text of the button
  • icon –  the Icon image to display on the button
/**
     * 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 Also:
  • updateUI.updateUI
/**
     * 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.

See Also:
Returns:the string "ButtonUI"
@beaninfo
       expert: true
  description: A string that specifies the name of the L&F class.
/**
     * 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 defaultButton property,
which if true means that this button is the current
default button for its JRootPane.
Most look and feels render the default button
differently, and may potentially provide bindings
to access the default button.

See Also:
Returns:the value of the defaultButton property
@beaninfo
 description: Whether or not this button is the default button
/**
     * 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 defaultCapable property.

See Also:
Returns:the value of the defaultCapable property
/**
     * 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 defaultCapable property,
which determines whether this button can be
made the default button for its root pane.
The default value of the defaultCapable
property is true unless otherwise
specified by the look and feel.

Params:
  • defaultCapable – true if this button will be
       capable of being the default button on the
       RootPane; otherwise false
See Also:
@beaninfo
       bound: true
   attribute: visualUpdate true
 description: Whether or not this button can be the default button
/**
     * 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 JComponent.removeNotify to check if
this button is currently set as the default button on the
RootPane, and if so, sets the RootPane's
default button to null to ensure the
RootPane doesn't hold onto an invalid button reference.

/**
     * 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.

/**
     * 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 JButton.
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 null.

Returns: a string representation of this JButton
/**
     * 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 AccessibleContext associated with this
JButton. For JButtons,
the AccessibleContext takes the form of an
AccessibleJButton.
A new AccessibleJButton instance is created if necessary.

Returns:an AccessibleJButton that serves as the
        AccessibleContext of this JButton
@beaninfo
      expert: true
 description: The AccessibleContext associated with this Button.
/**
     * 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
JButton class.  It provides an implementation of the
Java Accessibility API appropriate to button user-interface
elements.


Warning:
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 JavaBeansTM
has been added to the java.beans package. Please see XMLEncoder. 
/**
     * 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.

See Also:
Returns:an instance of AccessibleRole describing the role of the
object
/**
         * 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
}