- /*
- * @(#)JPanel.java 1.31 01/11/29
- *
- * Copyright 2002 Sun Microsystems, Inc. All rights reserved.
- * SUN PROPRIETARY/CONFIDENTIAL. Use is subject to license terms.
- */
- package javax.swing;
-
- import java.awt.*;
-
- import javax.swing.plaf.*;
- import javax.accessibility.*;
-
- import java.io.Serializable;
- import java.io.ObjectOutputStream;
- import java.io.ObjectInputStream;
- import java.io.IOException;
-
-
- /**
- * JPanel is a generic lightweight container.
- * <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. A future release of Swing will provide support for
- * long term persistence.
- *
- * @see <a href="http://java.sun.com/products/jfc/swingdoc-archive/mixing.html">
- * Mixing Heavy and Light Components</a>
- *
- * @beaninfo
- * description: A generic lightweight container.
- *
- * @version 1.31 11/29/01
- * @author Arnaud Weber
- * @author Steve Wilson
- */
- public class JPanel extends JComponent implements Accessible
- {
- /**
- * @see #getUIClassID
- * @see #readObject
- */
- private static final String uiClassID = "PanelUI";
-
- private static final FlowLayout defaultLayout = new FlowLayout();
-
- /**
- * Creates a new JPanel with the specified layout manager and buffering
- * strategy.
- *
- * @param layout the LayoutManager to use
- * @param isDoubleBuffered a boolean, true for double-buffering, which
- * uses additional memory space to achieve fast, flicker-free
- * updates
- */
- public JPanel(LayoutManager layout, boolean isDoubleBuffered) {
- setLayout(layout);
- setDoubleBuffered(isDoubleBuffered);
- setOpaque(true);
- updateUI();
- }
-
- /**
- * Create a new buffered JPanel with the specified layout manager
- *
- * @param layout the LayoutManager to use
- */
- public JPanel(LayoutManager layout) {
- this(layout, true);
- }
-
- /**
- * Create a new JPanel with FlowLayout and the specified buffering
- * strategy. If <code>isDoubleBuffered</code> is true, the JPanel
- * will use a double buffer.
- *
- * @param layout the LayoutManager to use
- * @param isDoubleBuffered a boolean, true for double-buffering, which
- * uses additional memory space to achieve fast, flicker-free
- * updates
- */
- public JPanel(boolean isDoubleBuffered) {
- this(defaultLayout, isDoubleBuffered);
- }
-
- /**
- * Create a new JPanel with a double buffer and a flow layout
- */
- public JPanel() {
- this(defaultLayout, true);
- }
-
- /**
- * Notification from the UIFactory that the L&F
- * has changed.
- *
- * @see JComponent#updateUI
- */
- public void updateUI() {
- setUI((PanelUI)UIManager.getUI(this));
- }
-
- /**
- * Returns a string that specifies the name of the L&F class
- * that renders this component.
- *
- * @return "PanelUI"
- * @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;
- }
-
-
- /**
- * See readObject() and writeObject() in JComponent for more
- * information about serialization in Swing.
- */
- private void writeObject(ObjectOutputStream s) throws IOException {
- s.defaultWriteObject();
- if ((ui != null) && (getUIClassID().equals(uiClassID))) {
- ui.installUI(this);
- }
- }
-
-
- /**
- * Returns a string representation of this JPanel. 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 JPanel.
- */
- protected String paramString() {
- String defaultLayoutString = (defaultLayout != null ?
- defaultLayout.toString() : "");
-
- return super.paramString() +
- ",defaultLayout=" + defaultLayoutString;
- }
-
- /////////////////
- // Accessibility support
- ////////////////
-
- /**
- * Get the AccessibleContext associated with this JComponent
- *
- * @return the AccessibleContext of this JComponent
- */
- public AccessibleContext getAccessibleContext() {
- if (accessibleContext == null) {
- accessibleContext = new AccessibleJPanel();
- }
- return accessibleContext;
- }
-
- /**
- * The class used to obtain the accessible role for this object.
- * <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. A future release of Swing will provide support for
- * long term persistence.
- */
- protected class AccessibleJPanel extends AccessibleJComponent {
-
- /**
- * Get the role of this object.
- *
- * @return an instance of AccessibleRole describing the role of the
- * object
- */
- public AccessibleRole getAccessibleRole() {
- return AccessibleRole.PANEL;
- }
- }
- }
-