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 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.

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 * This code is free software; you can redistribute it and/or modify it

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 * published by the Free Software Foundation.  Oracle designates this

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

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 * 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

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 *

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package javax.swing;

import java.awt.*;

import java.awt.event.*;

import java.beans.ConstructorProperties;

import java.util.Locale;

import java.io.Serializable;

import javax.accessibility.*;

/**

 * A lightweight container

 * that uses a BoxLayout object as its layout manager.

 * Box provides several class methods

 * that are useful for containers using BoxLayout --

 * even non-Box containers.

 *

 * <p>

 * The <code>Box</code> class can create several kinds

 * of invisible components

 * that affect layout:

 * glue, struts, and rigid areas.

 * If all the components your <code>Box</code> contains

 * have a fixed size,

 * you might want to use a glue component

 * (returned by <code>createGlue</code>)

 * to control the components' positions.

 * If you need a fixed amount of space between two components,

 * try using a strut

 * (<code>createHorizontalStrut</code> or <code>createVerticalStrut</code>).

 * If you need an invisible component

 * that always takes up the same amount of space,

 * get it by invoking <code>createRigidArea</code>.

 * <p>

 * If you are implementing a <code>BoxLayout</code> you

 * can find further information and examples in

 * <a

 href="http://java.sun.com/docs/books/tutorial/uiswing/layout/box.html">How to Use BoxLayout</a>,

 * a section in <em>The Java Tutorial.</em>

 * <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}.

 *

 * @see BoxLayout

 *

 * @author  Timothy Prinzing

 */

public class Box extends JComponent implements Accessible {

    /**

     * Creates a <code>Box</code> that displays its components

     * along the the specified axis.

     *

     * @param axis  can be {@link BoxLayout#X_AXIS},

     *              {@link BoxLayout#Y_AXIS},

     *              {@link BoxLayout#LINE_AXIS} or

     *              {@link BoxLayout#PAGE_AXIS}.

     * @throws AWTError if the <code>axis</code> is invalid

     * @see #createHorizontalBox

     * @see #createVerticalBox

     */

    public Box(int axis) {

        super();

        super.setLayout(new BoxLayout(this, axis));

    }

    /**

     * Creates a <code>Box</code> that displays its components

     * from left to right. If you want a <code>Box</code> that

     * respects the component orientation you should create the

     * <code>Box</code> using the constructor and pass in

     * <code>BoxLayout.LINE_AXIS</code>, eg:

     * <pre>

     *   Box lineBox = new Box(BoxLayout.LINE_AXIS);

     * </pre>

     *

     * @return the box

     */

    public static Box createHorizontalBox() {

        return new Box(BoxLayout.X_AXIS);

    }

    /**

     * Creates a <code>Box</code> that displays its components

     * from top to bottom. If you want a <code>Box</code> that

     * respects the component orientation you should create the

     * <code>Box</code> using the constructor and pass in

     * <code>BoxLayout.PAGE_AXIS</code>, eg:

     * <pre>

     *   Box lineBox = new Box(BoxLayout.PAGE_AXIS);

     * </pre>

     *

     * @return the box

     */

    public static Box createVerticalBox() {

        return new Box(BoxLayout.Y_AXIS);

    }

    /**

     * Creates an invisible component that's always the specified size.

     * <!-- WHEN WOULD YOU USE THIS AS OPPOSED TO A STRUT? -->

     *

     * @param d the dimensions of the invisible component

     * @return the component

     * @see #createGlue

     * @see #createHorizontalStrut

     * @see #createVerticalStrut

     */

    public static Component createRigidArea(Dimension d) {

        return new Filler(d, d, d);

    }

    /**

     * Creates an invisible, fixed-width component.

     * In a horizontal box,

     * you typically use this method

     * to force a certain amount of space between two components.

     * In a vertical box,

     * you might use this method

     * to force the box to be at least the specified width.

     * The invisible component has no height

     * unless excess space is available,

     * in which case it takes its share of available space,

     * just like any other component that has no maximum height.

     *

     * @param width the width of the invisible component, in pixels >= 0

     * @return the component

     * @see #createVerticalStrut

     * @see #createGlue

     * @see #createRigidArea

     */

    public static Component createHorizontalStrut(int width) {

        return new Filler(new Dimension(width,0), new Dimension(width,0),

                          new Dimension(width, Short.MAX_VALUE));

    }

    /**

     * Creates an invisible, fixed-height component.

     * In a vertical box,

     * you typically use this method

     * to force a certain amount of space between two components.

     * In a horizontal box,

     * you might use this method

     * to force the box to be at least the specified height.

     * The invisible component has no width

     * unless excess space is available,

     * in which case it takes its share of available space,

     * just like any other component that has no maximum width.

     *

     * @param height the height of the invisible component, in pixels >= 0

     * @return the component

     * @see #createHorizontalStrut

     * @see #createGlue

     * @see #createRigidArea

     */

    public static Component createVerticalStrut(int height) {

        return new Filler(new Dimension(0,height), new Dimension(0,height),

                          new Dimension(Short.MAX_VALUE, height));

    }

    /**

     * Creates an invisible "glue" component

     * that can be useful in a Box

     * whose visible components have a maximum width

     * (for a horizontal box)

     * or height (for a vertical box).

     * You can think of the glue component

     * as being a gooey substance

     * that expands as much as necessary

     * to fill the space between its neighboring components.

     *

     * <p>

     *

     * For example, suppose you have

     * a horizontal box that contains two fixed-size components.

     * If the box gets extra space,

     * the fixed-size components won't become larger,

    * so where does the extra space go?

     * Without glue,

     * the extra space goes to the right of the second component.

     * If you put glue between the fixed-size components,

     * then the extra space goes there.

     * If you put glue before the first fixed-size component,

     * the extra space goes there,

     * and the fixed-size components are shoved against the right

     * edge of the box.

     * If you put glue before the first fixed-size component

     * and after the second fixed-size component,

     * the fixed-size components are centered in the box.

     *

     * <p>

     *

     * To use glue,

     * call <code>Box.createGlue</code>

     * and add the returned component to a container.

     * The glue component has no minimum or preferred size,

     * so it takes no space unless excess space is available.

     * If excess space is available,

     * then the glue component takes its share of available

     * horizontal or vertical space,

     * just like any other component that has no maximum width or height.

     *

     * @return the component

     */

    public static Component createGlue() {

        return new Filler(new Dimension(0,0), new Dimension(0,0),

                          new Dimension(Short.MAX_VALUE, Short.MAX_VALUE));

    }

    /**

     * Creates a horizontal glue component.

     *

     * @return the component

     */

    public static Component createHorizontalGlue() {

        return new Filler(new Dimension(0,0), new Dimension(0,0),

                          new Dimension(Short.MAX_VALUE, 0));

    }

    /**

     * Creates a vertical glue component.

     *

     * @return the component

     */

    public static Component createVerticalGlue() {

        return new Filler(new Dimension(0,0), new Dimension(0,0),

                          new Dimension(0, Short.MAX_VALUE));

    }

    /**

     * Throws an AWTError, since a Box can use only a BoxLayout.

     *

     * @param l the layout manager to use

     */

    public void setLayout(LayoutManager l) {

        throw new AWTError("Illegal request");

    }

    /**

     * Paints this <code>Box</code>.  If this <code>Box</code> has a UI this

     * method invokes super's implementation, otherwise if this

     * <code>Box</code> is opaque the <code>Graphics</code> is filled

     * using the background.

     *

     * @param g the <code>Graphics</code> to paint to

     * @throws NullPointerException if <code>g</code> is null

     * @since 1.6

     */

    protected void paintComponent(Graphics g) {

        if (ui != null) {

            // On the off chance some one created a UI, honor it

            super.paintComponent(g);

        } else if (isOpaque()) {

            g.setColor(getBackground());

            g.fillRect(0, 0, getWidth(), getHeight());

        }

    }

    /**

     * An implementation of a lightweight component that participates in

     * layout but has no view.

     * <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}.

     */

    public static class Filler extends JComponent implements Accessible {

        /**

         * Constructor to create shape with the given size ranges.

         *

         * @param min   Minimum size

         * @param pref  Preferred size

         * @param max   Maximum size

         */

        @ConstructorProperties({"minimumSize", "preferredSize", "maximumSize"})

        public Filler(Dimension min, Dimension pref, Dimension max) {

            setMinimumSize(min);

            setPreferredSize(pref);

            setMaximumSize(max);

        }

        /**

         * Change the size requests for this shape.  An invalidate() is

         * propagated upward as a result so that layout will eventually

         * happen with using the new sizes.

         *

         * @param min   Value to return for getMinimumSize

         * @param pref  Value to return for getPreferredSize

         * @param max   Value to return for getMaximumSize

         */

        public void changeShape(Dimension min, Dimension pref, Dimension max) {

            setMinimumSize(min);

            setPreferredSize(pref);

            setMaximumSize(max);

            revalidate();

        }

        // ---- Component methods ------------------------------------------

        /**

         * Paints this <code>Filler</code>.  If this

         * <code>Filler</code> has a UI this method invokes super's

         * implementation, otherwise if this <code>Filler</code> is

         * opaque the <code>Graphics</code> is filled using the

         * background.

         *

         * @param g the <code>Graphics</code> to paint to

         * @throws NullPointerException if <code>g</code> is null

         * @since 1.6

         */

        protected void paintComponent(Graphics g) {

            if (ui != null) {

                // On the off chance some one created a UI, honor it

                super.paintComponent(g);

            } else if (isOpaque()) {

                g.setColor(getBackground());

                g.fillRect(0, 0, getWidth(), getHeight());

            }

        }

/////////////////

// Accessibility support for Box$Filler

////////////////

        /**

         * Gets the AccessibleContext associated with this Box.Filler.

         * For box fillers, the AccessibleContext takes the form of an

         * AccessibleBoxFiller.

         * A new AccessibleAWTBoxFiller instance is created if necessary.

         *

         * @return an AccessibleBoxFiller that serves as the

         *         AccessibleContext of this Box.Filler.

         */

        public AccessibleContext getAccessibleContext() {

            if (accessibleContext == null) {

                accessibleContext = new AccessibleBoxFiller();

            }

            return accessibleContext;

        }

        /**

         * This class implements accessibility support for the

         * <code>Box.Filler</code> class.

         */

        protected class AccessibleBoxFiller extends AccessibleAWTComponent {

            // AccessibleContext methods

            //

            /**

             * Gets the role of this object.

             *

             * @return an instance of AccessibleRole describing the role of

             *   the object (AccessibleRole.FILLER)

             * @see AccessibleRole

             */

            public AccessibleRole getAccessibleRole() {

                return AccessibleRole.FILLER;

            }

        }

    }

/////////////////

// Accessibility support for Box

////////////////

    /**

     * Gets the AccessibleContext associated with this Box.

     * For boxes, the AccessibleContext takes the form of an

     * AccessibleBox.

     * A new AccessibleAWTBox instance is created if necessary.

     *

     * @return an AccessibleBox that serves as the

     *         AccessibleContext of this Box

     */

    public AccessibleContext getAccessibleContext() {

        if (accessibleContext == null) {

            accessibleContext = new AccessibleBox();

        }

        return accessibleContext;

    }

    /**

     * This class implements accessibility support for the

     * <code>Box</code> class.

     */

    protected class AccessibleBox extends AccessibleAWTContainer {

        // AccessibleContext methods

        //

        /**

         * Gets the role of this object.

         *

         * @return an instance of AccessibleRole describing the role of the

         *   object (AccessibleRole.FILLER)

         * @see AccessibleRole

         */

        public AccessibleRole getAccessibleRole() {

            return AccessibleRole.FILLER;

        }

    } // inner class AccessibleBox

}