https://openjdk.java.net/ 
/*
 * Copyright (c) 1997, 2013, 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 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.


The Box class can create several kinds
of invisible components
that affect layout:
glue, struts, and rigid areas.
If all the components your Box contains
have a fixed size,
you might want to use a glue component
(returned by createGlue)
to control the components' positions.
If you need a fixed amount of space between two components,
try using a strut
(createHorizontalStrut or createVerticalStrut).
If you need an invisible component
that always takes up the same amount of space,
get it by invoking createRigidArea.


If you are implementing a BoxLayout you
can find further information and examples in
How to Use BoxLayout,
a section in The Java Tutorial.


Warning:
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™
has been added to the java.beans package. Please see XMLEncoder. 
Author: Timothy Prinzing
See Also:
/**
 * 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="https://docs.oracle.com/javase/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&trade;
 * has been added to the <code>java.beans</code> package.
 * Please see {@link java.beans.XMLEncoder}.
 *
 * @see BoxLayout
 *
 * @author  Timothy Prinzing
 */
@SuppressWarnings("serial")
public class Box extends JComponent implements Accessible {

    
Creates a Box that displays its components
along the the specified axis.

Params:
Throws:
See Also:
/**
     * 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 Box that displays its components
from left to right. If you want a Box that
respects the component orientation you should create the
Box using the constructor and pass in
BoxLayout.LINE_AXIS, eg:

  Box lineBox = new Box(BoxLayout.LINE_AXIS);



Returns:the box
/**
     * 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 Box that displays its components
from top to bottom. If you want a Box that
respects the component orientation you should create the
Box using the constructor and pass in
BoxLayout.PAGE_AXIS, eg:

  Box lineBox = new Box(BoxLayout.PAGE_AXIS);



Returns:the box
/**
     * 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.


Params:
  • d – the dimensions of the invisible component
See Also:
Returns:the component
/**
     * 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.

Params:
  • width – the width of the invisible component, in pixels >= 0
See Also:
Returns:the component
/**
     * 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 &gt;= 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.

Params:
  • height – the height of the invisible component, in pixels >= 0
See Also:
Returns:the component
/**
     * 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 &gt;= 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.


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.


To use glue,
call Box.createGlue
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.

Returns:the component
/**
     * 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.

Returns:the component
/**
     * 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.

Returns:the component
/**
     * 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.

Params:
  • l – the layout manager to use
/**
     * 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 Box.  If this Box has a UI this
method invokes super's implementation, otherwise if this
Box is opaque the Graphics is filled
using the background.

Params:
  • g – the Graphics to paint to
Throws:
Since:1.6
/**
     * 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.


Warning:
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™
has been added to the java.beans package. Please see XMLEncoder. 
/**
     * 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&trade;
     * has been added to the <code>java.beans</code> package.
     * Please see {@link java.beans.XMLEncoder}.
     */
    @SuppressWarnings("serial")
    public static class Filler extends JComponent implements Accessible {

        
Constructor to create shape with the given size ranges.

Params:
  • min –   Minimum size
  • pref –  Preferred size
  • max –   Maximum size
/**
         * 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.

Params:
  • min –   Value to return for getMinimumSize
  • pref –  Value to return for getPreferredSize
  • max –   Value to return for getMaximumSize
/**
         * 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 Filler.  If this
Filler has a UI this method invokes super's
implementation, otherwise if this Filler is
opaque the Graphics is filled using the
background.

Params:
  • g – the Graphics to paint to
Throws:
Since:1.6
/**
         * 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.

Returns:an AccessibleBoxFiller that serves as the
        AccessibleContext of this 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
Box.Filler class.

/**
         * This class implements accessibility support for the
         * <code>Box.Filler</code> class.
         */
        @SuppressWarnings("serial")
        protected class AccessibleBoxFiller extends AccessibleAWTComponent {
            // AccessibleContext methods
            //
            
Gets the role of this object.

See Also:
Returns:an instance of AccessibleRole describing the role of
  the object (AccessibleRole.FILLER)
/**
             * 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.

Returns:an AccessibleBox that serves as the
        AccessibleContext of this 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
Box class.

/**
     * This class implements accessibility support for the
     * <code>Box</code> class.
     */
    @SuppressWarnings("serial")
    protected class AccessibleBox extends AccessibleAWTContainer {
        // AccessibleContext methods
        //
        
Gets the role of this object.

See Also:
Returns:an instance of AccessibleRole describing the role of the
  object (AccessibleRole.FILLER)
/**
         * 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
}