/*

 * Copyright 1995-2007 Sun Microsystems, Inc.  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.  Sun designates this

 * particular file as subject to the "Classpath" exception as provided

 * by Sun 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 Sun Microsystems, Inc., 4150 Network Circle, Santa Clara,

 * CA 95054 USA or visit www.sun.com if you need additional information or

 * have any questions.

 */

package java.awt;

import javax.accessibility.*;

/**

 * <code>Panel</code> is the simplest container class. A panel

 * provides space in which an application can attach any other

 * component, including other panels.

 * <p>

 * The default layout manager for a panel is the

 * <code>FlowLayout</code> layout manager.

 *

 * @author      Sami Shaio

 * @see     java.awt.FlowLayout

 * @since   JDK1.0

 */

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</code> class.

     */

    public Panel() {

        this(new FlowLayout());

    }

    /**

     * Creates a new panel with the specified layout manager.

     * @param layout the layout manager for this panel.

     * @since JDK1.1

     */

    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 = getToolkit().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</code> 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;

        }

    }

}