META-INF.modules.java.desktop.classes.java.awt.Panel Maven / Gradle / Ivy
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/*
* Copyright (c) 1995, 2015, 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 java.awt;
import javax.accessibility.*;
/**
* {@code Panel} is the simplest container class. A panel
* provides space in which an application can attach any other
* component, including other panels.
*
* The default layout manager for a panel is the
* {@code FlowLayout} layout manager.
*
* @author Sami Shaio
* @see java.awt.FlowLayout
* @since 1.0
*/
public class Panel extends Container implements Accessible {
private static final String base = "panel";
private static int nameCounter = 0;
/*
* JDK 1.1 serialVersionUID
*/
private static final long serialVersionUID = -2728009084054400034L;
/**
* Creates a new panel using the default layout manager.
* The default layout manager for all panels is the
* {@code FlowLayout} class.
*/
public Panel() {
this(new FlowLayout());
}
/**
* Creates a new panel with the specified layout manager.
* @param layout the layout manager for this panel.
* @since 1.1
*/
public Panel(LayoutManager layout) {
setLayout(layout);
}
/**
* Construct a name for this component. Called by getName() when the
* name is null.
*/
String constructComponentName() {
synchronized (Panel.class) {
return base + nameCounter++;
}
}
/**
* Creates the Panel's peer. The peer allows you to modify the
* appearance of the panel without changing its functionality.
*/
public void addNotify() {
synchronized (getTreeLock()) {
if (peer == null)
peer = getComponentFactory().createPanel(this);
super.addNotify();
}
}
/////////////////
// Accessibility support
////////////////
/**
* Gets the AccessibleContext associated with this Panel.
* For panels, the AccessibleContext takes the form of an
* AccessibleAWTPanel.
* A new AccessibleAWTPanel instance is created if necessary.
*
* @return an AccessibleAWTPanel that serves as the
* AccessibleContext of this Panel
* @since 1.3
*/
public AccessibleContext getAccessibleContext() {
if (accessibleContext == null) {
accessibleContext = new AccessibleAWTPanel();
}
return accessibleContext;
}
/**
* This class implements accessibility support for the
* {@code Panel} class. It provides an implementation of the
* Java Accessibility API appropriate to panel user-interface elements.
* @since 1.3
*/
protected class AccessibleAWTPanel extends AccessibleAWTContainer {
private static final long serialVersionUID = -6409552226660031050L;
/**
* Get the role of this object.
*
* @return an instance of AccessibleRole describing the role of the
* object
*/
public AccessibleRole getAccessibleRole() {
return AccessibleRole.PANEL;
}
}
}