https://openjdk.java.net/ 
/*
 * Copyright (c) 1997, 2020, 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.applet.Applet;
import java.awt.AWTEvent;
import java.awt.BorderLayout;
import java.awt.Color;
import java.awt.Component;
import java.awt.Container;
import java.awt.Graphics;
import java.awt.HeadlessException;
import java.awt.LayoutManager;
import java.beans.BeanProperty;
import java.beans.JavaBean;

import javax.accessibility.Accessible;
import javax.accessibility.AccessibleContext;


An extended version of java.applet.Applet that adds support for
the JFC/Swing component architecture.
You can find task-oriented documentation about using JApplet
in The Java Tutorial,
in the section
How to Make Applets.


The JApplet class is slightly incompatible with
java.applet.Applet.  JApplet contains a
JRootPane as its only child.  The contentPane
should be the parent of any children of the JApplet. As a convenience, the add, remove, and setLayout methods of this class are overridden, so that they delegate calls to the corresponding methods of the ContentPane. For example, you can add a child component to an applet as follows: 
      applet.add(child);


And the child will be added to the contentPane.
The contentPane will always be non-null.
Attempting to set it to null will cause the
JApplet to throw an exception. The default
contentPane will have a BorderLayout manager set on it. Refer to RootPaneContainer for details on adding, removing and setting the LayoutManager
of a JApplet.


Please see the JRootPane documentation for a
complete description of the contentPane, glassPane,
and layeredPane properties.


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 JavaBeans
has been added to the java.beans package. Please see XMLEncoder. 
Author:Arnaud Weber
See Also:
Since:1.2
Deprecated:The Applet API is deprecated, no replacement.
/**
 * An extended version of <code>java.applet.Applet</code> that adds support for
 * the JFC/Swing component architecture.
 * You can find task-oriented documentation about using <code>JApplet</code>
 * in <em>The Java Tutorial</em>,
 * in the section
 * <a
 href="https://docs.oracle.com/javase/tutorial/uiswing/components/applet.html">How to Make Applets</a>.
 * <p>
 * The <code>JApplet</code> class is slightly incompatible with
 * <code>java.applet.Applet</code>.  <code>JApplet</code> contains a
 * <code>JRootPane</code> as its only child.  The <code>contentPane</code>
 * should be the parent of any children of the <code>JApplet</code>.
 * As a convenience, the {@code add}, {@code remove}, and {@code setLayout}
 * methods of this class are overridden, so that they delegate calls
 * to the corresponding methods of the {@code ContentPane}.
 * For example, you can add a child component to an applet as follows:
 * <pre>
 *       applet.add(child);
 * </pre>
 *
 * And the child will be added to the <code>contentPane</code>.
 * The <code>contentPane</code> will always be non-<code>null</code>.
 * Attempting to set it to <code>null</code> will cause the
 * <code>JApplet</code> to throw an exception. The default
 * <code>contentPane</code> will have a <code>BorderLayout</code>
 * manager set on it.
 * Refer to {@link javax.swing.RootPaneContainer}
 * for details on adding, removing and setting the <code>LayoutManager</code>
 * of a <code>JApplet</code>.
 * <p>
 * Please see the <code>JRootPane</code> documentation for a
 * complete description of the <code>contentPane</code>, <code>glassPane</code>,
 * and <code>layeredPane</code> properties.
 * <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
 * has been added to the <code>java.beans</code> package.
 * Please see {@link java.beans.XMLEncoder}.
 *
 * @see javax.swing.RootPaneContainer
 *
 * @author Arnaud Weber
 * @since 1.2
 *
 * @deprecated The Applet API is deprecated, no replacement.
 */
@Deprecated(since = "9")
@JavaBean(defaultProperty = "JMenuBar", description = "Swing's Applet subclass.")
@SwingContainer(delegate = "getContentPane")
@SuppressWarnings("serial") // Same-version serialization only
public class JApplet extends Applet implements Accessible,
                                               RootPaneContainer,
                               TransferHandler.HasGetTransferHandler
{
    
See Also:
/**
     * @see #getRootPane
     * @see #setRootPane
     */
    protected JRootPane rootPane;

    
If true then calls to add and setLayout
will be forwarded to the contentPane. This is initially
false, but is set to true when the JApplet is constructed.

See Also:
/**
     * If true then calls to <code>add</code> and <code>setLayout</code>
     * will be forwarded to the <code>contentPane</code>. This is initially
     * false, but is set to true when the <code>JApplet</code> is constructed.
     *
     * @see #isRootPaneCheckingEnabled
     * @see #setRootPaneCheckingEnabled
     * @see javax.swing.RootPaneContainer
     */
    protected boolean rootPaneCheckingEnabled = false;

    
The TransferHandler for this applet.

/**
     * The <code>TransferHandler</code> for this applet.
     */
    private TransferHandler transferHandler;

    
Creates a swing applet instance.


This constructor sets the component's locale property to the value
returned by JComponent.getDefaultLocale.

Throws:
  • HeadlessException – if GraphicsEnvironment.isHeadless()
returns true.
See Also:
/**
     * Creates a swing applet instance.
     * <p>
     * This constructor sets the component's locale property to the value
     * returned by <code>JComponent.getDefaultLocale</code>.
     *
     * @exception HeadlessException if GraphicsEnvironment.isHeadless()
     * returns true.
     * @see java.awt.GraphicsEnvironment#isHeadless
     * @see JComponent#getDefaultLocale
     */
    public JApplet() throws HeadlessException {
        super();
        // Check the timerQ and restart if necessary.
        TimerQueue q = TimerQueue.sharedInstance();
        if(q != null) {
            q.startIfNeeded();
        }

        /* Workaround for bug 4155072.  The shared double buffer image
         * may hang on to a reference to this applet; unfortunately
         * Image.getGraphics() will continue to call JApplet.getForeground()
         * and getBackground() even after this applet has been destroyed.
         * So we ensure that these properties are non-null here.
         */
        setForeground(Color.black);
        setBackground(Color.white);

        setLocale( JComponent.getDefaultLocale() );
        setLayout(new BorderLayout());
        setRootPane(createRootPane());
        setRootPaneCheckingEnabled(true);

        setFocusTraversalPolicyProvider(true);
        sun.awt.SunToolkit.checkAndSetPolicy(this);

        enableEvents(AWTEvent.KEY_EVENT_MASK);
    }

    
Called by the constructor methods to create the default rootPane.

Returns: a new JRootPane
/**
     * Called by the constructor methods to create the default rootPane.
     *
     * @return  a new {@code JRootPane}
     */
    protected JRootPane createRootPane() {
        JRootPane rp = new JRootPane();
        // NOTE: this uses setOpaque vs LookAndFeel.installProperty as there
        // is NO reason for the RootPane not to be opaque. For painting to
        // work the contentPane must be opaque, therefor the RootPane can
        // also be opaque.
        rp.setOpaque(true);
        return rp;
    }

    
Sets the transferHandler property, which is a mechanism to support transfer of data into this component. Use null if the component does not support data transfer operations. 
 If the system property suppressSwingDropSupport is false (the default) and the current drop target on this component is either null or not a user-set drop target, this method will change the drop target as follows: If newHandler is null it will clear the drop target. If not null it will install a new DropTarget. 
 Note: When used with JApplet, TransferHandler only provides data import capability, as the data export related methods are currently typed to JComponent. 

Please see

How to Use Drag and Drop and Data Transfer, a section in
The Java Tutorial, for more information.

Params:
  • newHandler – the new TransferHandler
See Also:
Since:1.6
/**
     * Sets the {@code transferHandler} property, which is a mechanism to
     * support transfer of data into this component. Use {@code null}
     * if the component does not support data transfer operations.
     * <p>
     * If the system property {@code suppressSwingDropSupport} is {@code false}
     * (the default) and the current drop target on this component is either
     * {@code null} or not a user-set drop target, this method will change the
     * drop target as follows: If {@code newHandler} is {@code null} it will
     * clear the drop target. If not {@code null} it will install a new
     * {@code DropTarget}.
     * <p>
     * Note: When used with {@code JApplet}, {@code TransferHandler} only
     * provides data import capability, as the data export related methods
     * are currently typed to {@code JComponent}.
     * <p>
     * Please see
     * <a href="https://docs.oracle.com/javase/tutorial/uiswing/dnd/index.html">
     * How to Use Drag and Drop and Data Transfer</a>, a section in
     * <em>The Java Tutorial</em>, for more information.
     *
     * @param newHandler the new {@code TransferHandler}
     *
     * @see TransferHandler
     * @see #getTransferHandler
     * @see java.awt.Component#setDropTarget
     * @since 1.6
     */
    @BeanProperty(hidden = true, description
            = "Mechanism for transfer of data into the component")
    public void setTransferHandler(TransferHandler newHandler) {
        TransferHandler oldHandler = transferHandler;
        transferHandler = newHandler;
        SwingUtilities.installSwingDropTargetAsNecessary(this, transferHandler);
        firePropertyChange("transferHandler", oldHandler, newHandler);
    }

    
Gets the transferHandler property.

See Also:
Returns:the value of the transferHandler property
Since:1.6
/**
     * Gets the <code>transferHandler</code> property.
     *
     * @return the value of the <code>transferHandler</code> property
     *
     * @see TransferHandler
     * @see #setTransferHandler
     * @since 1.6
     */
    public TransferHandler getTransferHandler() {
        return transferHandler;
    }

    
Just calls paint(g).  This method was overridden to
prevent an unnecessary call to clear the background.

/**
     * Just calls <code>paint(g)</code>.  This method was overridden to
     * prevent an unnecessary call to clear the background.
     */
    public void update(Graphics g) {
        paint(g);
    }

   
Sets the menubar for this applet.

Params:
  • menuBar – the menubar being placed in the applet
See Also:
/**
    * Sets the menubar for this applet.
    * @param menuBar the menubar being placed in the applet
    *
    * @see #getJMenuBar
    */
    @BeanProperty(bound = false, hidden = true, description
            = "The menubar for accessing pulldown menus from this applet.")
    public void setJMenuBar(final JMenuBar menuBar) {
        getRootPane().setJMenuBar(menuBar);
    }

   
Returns the menubar set on this applet.

See Also:
Returns:the menubar set on this applet
/**
    * Returns the menubar set on this applet.
    *
    * @return the menubar set on this applet
    * @see #setJMenuBar
    */
    public JMenuBar getJMenuBar() {
        return getRootPane().getJMenuBar();
    }


    
Returns whether calls to add and
setLayout are forwarded to the contentPane.

See Also:
Returns:true if add and setLayout
        are forwarded; false otherwise
/**
     * Returns whether calls to <code>add</code> and
     * <code>setLayout</code> are forwarded to the <code>contentPane</code>.
     *
     * @return true if <code>add</code> and <code>setLayout</code>
     *         are forwarded; false otherwise
     *
     * @see #addImpl
     * @see #setLayout
     * @see #setRootPaneCheckingEnabled
     * @see javax.swing.RootPaneContainer
     */
    protected boolean isRootPaneCheckingEnabled() {
        return rootPaneCheckingEnabled;
    }


    
Sets whether calls to add and
setLayout are forwarded to the contentPane.

Params:
  • enabled –  true if add and setLayout
       are forwarded, false if they should operate directly on the
       JApplet.
See Also:
/**
     * Sets whether calls to <code>add</code> and
     * <code>setLayout</code> are forwarded to the <code>contentPane</code>.
     *
     * @param enabled  true if <code>add</code> and <code>setLayout</code>
     *        are forwarded, false if they should operate directly on the
     *        <code>JApplet</code>.
     *
     * @see #addImpl
     * @see #setLayout
     * @see #isRootPaneCheckingEnabled
     * @see javax.swing.RootPaneContainer
     */
    @BeanProperty(hidden = true, description
            = "Whether the add and setLayout methods are forwarded")
    protected void setRootPaneCheckingEnabled(boolean enabled) {
        rootPaneCheckingEnabled = enabled;
    }


    
Adds the specified child Component.
This method is overridden to conditionally forward calls to the
contentPane.
By default, children are added to the contentPane instead of the frame, refer to RootPaneContainer for details. 
Params:
  • comp – the component to be enhanced
  • constraints – the constraints to be respected
  • index – the index
Throws:
See Also:
/**
     * Adds the specified child <code>Component</code>.
     * This method is overridden to conditionally forward calls to the
     * <code>contentPane</code>.
     * By default, children are added to the <code>contentPane</code> instead
     * of the frame, refer to {@link javax.swing.RootPaneContainer} for
     * details.
     *
     * @param comp the component to be enhanced
     * @param constraints the constraints to be respected
     * @param index the index
     * @exception IllegalArgumentException if <code>index</code> is invalid
     * @exception IllegalArgumentException if adding the container's parent
     *                  to itself
     * @exception IllegalArgumentException if adding a window to a container
     *
     * @see #setRootPaneCheckingEnabled
     * @see javax.swing.RootPaneContainer
     */
    protected void addImpl(Component comp, Object constraints, int index)
    {
        if(isRootPaneCheckingEnabled()) {
            getContentPane().add(comp, constraints, index);
        }
        else {
            super.addImpl(comp, constraints, index);
        }
    }

    
Removes the specified component from the container. If
comp is not the rootPane, this will forward
the call to the contentPane. This will do nothing if
comp is not a child of the JFrame or
contentPane.

Params:
  • comp – the component to be removed
Throws:
See Also:
/**
     * Removes the specified component from the container. If
     * <code>comp</code> is not the <code>rootPane</code>, this will forward
     * the call to the <code>contentPane</code>. This will do nothing if
     * <code>comp</code> is not a child of the <code>JFrame</code> or
     * <code>contentPane</code>.
     *
     * @param comp the component to be removed
     * @throws NullPointerException if <code>comp</code> is null
     * @see #add
     * @see javax.swing.RootPaneContainer
     */
    public void remove(Component comp) {
        if (comp == rootPane) {
            super.remove(comp);
        } else {
            getContentPane().remove(comp);
        }
    }


    
Sets the LayoutManager.
Overridden to conditionally forward the call to the
contentPane. Refer to RootPaneContainer for more information. 
Params:
  • manager – the LayoutManager
See Also:
/**
     * Sets the <code>LayoutManager</code>.
     * Overridden to conditionally forward the call to the
     * <code>contentPane</code>.
     * Refer to {@link javax.swing.RootPaneContainer} for
     * more information.
     *
     * @param manager the <code>LayoutManager</code>
     * @see #setRootPaneCheckingEnabled
     * @see javax.swing.RootPaneContainer
     */
    public void setLayout(LayoutManager manager) {
        if(isRootPaneCheckingEnabled()) {
            getContentPane().setLayout(manager);
        }
        else {
            super.setLayout(manager);
        }
    }


    
Returns the rootPane object for this applet.

See Also:
/**
     * Returns the rootPane object for this applet.
     *
     * @see #setRootPane
     * @see RootPaneContainer#getRootPane
     */
    @BeanProperty(bound = false, hidden = true, description
            = "the RootPane object for this applet.")
    public JRootPane getRootPane() {
        return rootPane;
    }


    
Sets the rootPane property.  This method is called by the constructor.

Params:
  • root – the rootPane object for this applet
See Also:
/**
     * Sets the rootPane property.  This method is called by the constructor.
     * @param root the rootPane object for this applet
     *
     * @see #getRootPane
     */
    protected void setRootPane(JRootPane root) {
        if(rootPane != null) {
            remove(rootPane);
        }
        rootPane = root;
        if(rootPane != null) {
            boolean checkingEnabled = isRootPaneCheckingEnabled();
            try {
                setRootPaneCheckingEnabled(false);
                add(rootPane, BorderLayout.CENTER);
            }
            finally {
                setRootPaneCheckingEnabled(checkingEnabled);
            }
        }
    }


    
Returns the contentPane object for this applet.

See Also:
/**
     * Returns the contentPane object for this applet.
     *
     * @see #setContentPane
     * @see RootPaneContainer#getContentPane
     */
    public Container getContentPane() {
        return getRootPane().getContentPane();
    }

   
Sets the contentPane property.  This method is called by the constructor.

Params:
  • contentPane – the contentPane object for this applet
Throws:
See Also:
/**
     * Sets the contentPane property.  This method is called by the constructor.
     * @param contentPane the contentPane object for this applet
     *
     * @exception java.awt.IllegalComponentStateException (a runtime
     *            exception) if the content pane parameter is null
     * @see #getContentPane
     * @see RootPaneContainer#setContentPane
     */
   @BeanProperty(bound = false, hidden = true, description
           = "The client area of the applet where child components are normally inserted.")
    public void setContentPane(Container contentPane) {
        getRootPane().setContentPane(contentPane);
    }

    
Returns the layeredPane object for this applet.

Throws:
  • IllegalComponentStateException – (a runtime
           exception) if the layered pane parameter is null
See Also:
/**
     * Returns the layeredPane object for this applet.
     *
     * @exception java.awt.IllegalComponentStateException (a runtime
     *            exception) if the layered pane parameter is null
     * @see #setLayeredPane
     * @see RootPaneContainer#getLayeredPane
     */
    public JLayeredPane getLayeredPane() {
        return getRootPane().getLayeredPane();
    }

    
Sets the layeredPane property.  This method is called by the constructor.

Params:
  • layeredPane – the layeredPane object for this applet
See Also:
/**
     * Sets the layeredPane property.  This method is called by the constructor.
     * @param layeredPane the layeredPane object for this applet
     *
     * @see #getLayeredPane
     * @see RootPaneContainer#setLayeredPane
     */
    @BeanProperty(bound = false, hidden = true, description
            = "The pane which holds the various applet layers.")
    public void setLayeredPane(JLayeredPane layeredPane) {
        getRootPane().setLayeredPane(layeredPane);
    }

    
Returns the glassPane object for this applet.

See Also:
/**
     * Returns the glassPane object for this applet.
     *
     * @see #setGlassPane
     * @see RootPaneContainer#getGlassPane
     */
    public Component getGlassPane() {
        return getRootPane().getGlassPane();
    }

    
Sets the glassPane property.
This method is called by the constructor.

Params:
  • glassPane – the glassPane object for this applet
See Also:
/**
     * Sets the glassPane property.
     * This method is called by the constructor.
     * @param glassPane the glassPane object for this applet
     *
     * @see #getGlassPane
     * @see RootPaneContainer#setGlassPane
     */
    @BeanProperty(bound = false, hidden = true, description
            = "A transparent pane used for menu rendering.")
    public void setGlassPane(Component glassPane) {
        getRootPane().setGlassPane(glassPane);
    }

    
{@inheritDoc}

Since:1.6
/**
     * {@inheritDoc}
     *
     * @since 1.6
     */
    @BeanProperty(bound = false)
    public Graphics getGraphics() {
        JComponent.getGraphicsInvoked(this);
        return super.getGraphics();
    }

    
Repaints the specified rectangle of this component within
time milliseconds.  Refer to RepaintManager
for details on how the repaint is handled.

Params:
  • time –   maximum time in milliseconds before update
  • x –    the x coordinate
  • y –    the y coordinate
  • width –    the width
  • height –   the height
See Also:
Since:    1.6
/**
     * Repaints the specified rectangle of this component within
     * <code>time</code> milliseconds.  Refer to <code>RepaintManager</code>
     * for details on how the repaint is handled.
     *
     * @param     time   maximum time in milliseconds before update
     * @param     x    the <i>x</i> coordinate
     * @param     y    the <i>y</i> coordinate
     * @param     width    the width
     * @param     height   the height
     * @see       RepaintManager
     * @since     1.6
     */
    public void repaint(long time, int x, int y, int width, int height) {
        if (RepaintManager.HANDLE_TOP_LEVEL_PAINT) {
            RepaintManager.currentManager(this).addDirtyRegion(
                              this, x, y, width, height);
        }
        else {
            super.repaint(time, x, y, width, height);
        }
    }

    
Returns a string representation of this JApplet. 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 JApplet.
/**
     * Returns a string representation of this JApplet. 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 JApplet.
     */
    protected String paramString() {
        String rootPaneString = (rootPane != null ?
                                 rootPane.toString() : "");
        String rootPaneCheckingEnabledString = (rootPaneCheckingEnabled ?
                                                "true" : "false");

        return super.paramString() +
        ",rootPane=" + rootPaneString +
        ",rootPaneCheckingEnabled=" + rootPaneCheckingEnabledString;
    }



/////////////////
// Accessibility support
////////////////

    
AccessibleContext associated with this JApplet 
/**
     * {@code AccessibleContext} associated with this {@code JApplet}
     */
    protected AccessibleContext accessibleContext = null;

    
Gets the AccessibleContext associated with this JApplet.
For JApplets, the AccessibleContext takes the form of an
AccessibleJApplet.
A new AccessibleJApplet instance is created if necessary.

Returns:an AccessibleJApplet that serves as the
        AccessibleContext of this JApplet
/**
     * Gets the AccessibleContext associated with this JApplet.
     * For JApplets, the AccessibleContext takes the form of an
     * AccessibleJApplet.
     * A new AccessibleJApplet instance is created if necessary.
     *
     * @return an AccessibleJApplet that serves as the
     *         AccessibleContext of this JApplet
     */
    public AccessibleContext getAccessibleContext() {
        if (accessibleContext == null) {
            accessibleContext = new AccessibleJApplet();
        }
        return accessibleContext;
    }

    
This class implements accessibility support for the
JApplet class.

/**
     * This class implements accessibility support for the
     * <code>JApplet</code> class.
     */
    protected class AccessibleJApplet extends AccessibleApplet {

        
Constructs an AccessibleJApplet. 
/**
         * Constructs an {@code AccessibleJApplet}.
         */
        protected AccessibleJApplet() {}

        // everything moved to new parent, AccessibleApplet
    }
}