/* * Copyright (c) 1997, 2006, 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.awt.*;import javax.swing.plaf.*;import javax.accessibility.*;import java.io.Serializable;import java.io.ObjectOutputStream;import java.io.ObjectInputStream;import java.io.IOException;/** * <code>JPanel</code> is a generic lightweight container. * For examples and task-oriented documentation for JPanel, see * <a href="http://java.sun.com/docs/books/tutorial/uiswing/components/panel.html">How to Use Panels</a>, * a section in <em>The Java Tutorial</em>. * <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 * description: A generic lightweight container. * * @author Arnaud Weber * @author Steve Wilson */public class JPanel extends JComponent implements Accessible{ /** * @see #getUIClassID * @see #readObject */ private static final String uiClassID = "PanelUI"; /** * 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); setUIProperty("opaque", Boolean.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); } /** * Creates a new <code>JPanel</code> with <code>FlowLayout</code> * and the specified buffering strategy. * If <code>isDoubleBuffered</code> is true, the <code>JPanel</code> * will use a double buffer. * * @param isDoubleBuffered a boolean, true for double-buffering, which * uses additional memory space to achieve fast, flicker-free * updates */ public JPanel(boolean isDoubleBuffered) { this(new FlowLayout(), isDoubleBuffered); } /** * Creates a new <code>JPanel</code> with a double buffer * and a flow layout. */ public JPanel() { this(true); } /** * Resets the UI property with a value from the current look and feel. * * @see JComponent#updateUI */ public void updateUI() { setUI((PanelUI)UIManager.getUI(this)); } /** * Returns the look and feel (L&F) object that renders this component. * * @return the PanelUI object that renders this component * @since 1.4 */ public PanelUI getUI() { return (PanelUI)ui; } /** * Sets the look and feel (L&F) object that renders this component. * * @param ui the PanelUI L&F object * @see UIDefaults#getUI * @since 1.4 * @beaninfo * bound: true * hidden: true * attribute: visualUpdate true * description: The UI object that implements the Component's LookAndFeel. */ public void setUI(PanelUI ui) { super.setUI(ui); } /** * 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 (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 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() { return super.paramString(); }/////////////////// Accessibility support//////////////// /** * Gets the AccessibleContext associated with this JPanel. * For JPanels, the AccessibleContext takes the form of an * AccessibleJPanel. * A new AccessibleJPanel instance is created if necessary. * * @return an AccessibleJPanel that serves as the * AccessibleContext of this JPanel */ public AccessibleContext getAccessibleContext() { if (accessibleContext == null) { accessibleContext = new AccessibleJPanel(); } return accessibleContext; } /** * This class implements accessibility support for the * <code>JPanel</code> class. It provides an implementation of the * Java Accessibility API appropriate to panel 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 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; } }}
/*
* Copyright (c) 1997, 2006, 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.awt.*;
import javax.swing.plaf.*;
import javax.accessibility.*;
import java.io.Serializable;
import java.io.ObjectOutputStream;
import java.io.ObjectInputStream;
import java.io.IOException;
/**
* <code>JPanel</code> is a generic lightweight container.
* For examples and task-oriented documentation for JPanel, see
* <a
href="http://java.sun.com/docs/books/tutorial/uiswing/components/panel.html">How to Use Panels</a>,
* a section in <em>The Java Tutorial</em>.
* <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
* description: A generic lightweight container.
*
* @author Arnaud Weber
* @author Steve Wilson
*/
public class JPanel extends JComponent implements Accessible
{
/**
* @see #getUIClassID
* @see #readObject
*/
private static final String uiClassID = "PanelUI";
/**
* 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);
setUIProperty("opaque", Boolean.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);
}
/**
* Creates a new <code>JPanel</code> with <code>FlowLayout</code>
* and the specified buffering strategy.
* If <code>isDoubleBuffered</code> is true, the <code>JPanel</code>
* will use a double buffer.
*
* @param isDoubleBuffered a boolean, true for double-buffering, which
* uses additional memory space to achieve fast, flicker-free
* updates
*/
public JPanel(boolean isDoubleBuffered) {
this(new FlowLayout(), isDoubleBuffered);
}
/**
* Creates a new <code>JPanel</code> with a double buffer
* and a flow layout.
*/
public JPanel() {
this(true);
}
/**
* Resets the UI property with a value from the current look and feel.
*
* @see JComponent#updateUI
*/
public void updateUI() {
setUI((PanelUI)UIManager.getUI(this));
}
/**
* Returns the look and feel (L&F) object that renders this component.
*
* @return the PanelUI object that renders this component
* @since 1.4
*/
public PanelUI getUI() {
return (PanelUI)ui;
}
/**
* Sets the look and feel (L&F) object that renders this component.
*
* @param ui the PanelUI L&F object
* @see UIDefaults#getUI
* @since 1.4
* @beaninfo
* bound: true
* hidden: true
* attribute: visualUpdate true
* description: The UI object that implements the Component's LookAndFeel.
*/
public void setUI(PanelUI ui) {
super.setUI(ui);
}
/**
* 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 (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 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() {
return super.paramString();
}
/////////////////
// Accessibility support
////////////////
/**
* Gets the AccessibleContext associated with this JPanel.
* For JPanels, the AccessibleContext takes the form of an
* AccessibleJPanel.
* A new AccessibleJPanel instance is created if necessary.
*
* @return an AccessibleJPanel that serves as the
* AccessibleContext of this JPanel
*/
public AccessibleContext getAccessibleContext() {
if (accessibleContext == null) {
accessibleContext = new AccessibleJPanel();
}
return accessibleContext;
}
/**
* This class implements accessibility support for the
* <code>JPanel</code> class. It provides an implementation of the
* Java Accessibility API appropriate to panel 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 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;
}
}
}