Java™ Platform
Standard Ed. 6

javax.swing
Class Box

java.lang.Object
  extended by java.awt.Component
      extended by java.awt.Container
          extended by javax.swing.JComponent
              extended by javax.swing.Box
All Implemented Interfaces:
ImageObserver, MenuContainer, Serializable, Accessible

public class Box
extends JComponent
implements Accessible

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 JavaBeansTM has been added to the java.beans package. Please see XMLEncoder.

See Also:
BoxLayout

Nested Class Summary
protected  class Box.AccessibleBox
          This class implements accessibility support for the Box class.
static class Box.Filler
          An implementation of a lightweight component that participates in layout but has no view.
 
Nested classes/interfaces inherited from class javax.swing.JComponent
JComponent.AccessibleJComponent
 
Nested classes/interfaces inherited from class java.awt.Container
Container.AccessibleAWTContainer
 
Nested classes/interfaces inherited from class java.awt.Component
Component.AccessibleAWTComponent, Component.BaselineResizeBehavior, Component.BltBufferStrategy, Component.FlipBufferStrategy
 
Field Summary
 
Fields inherited from class javax.swing.JComponent
accessibleContext, listenerList, TOOL_TIP_TEXT_KEY, ui, UNDEFINED_CONDITION, WHEN_ANCESTOR_OF_FOCUSED_COMPONENT, WHEN_FOCUSED, WHEN_IN_FOCUSED_WINDOW
 
Fields inherited from class java.awt.Component
BOTTOM_ALIGNMENT, CENTER_ALIGNMENT, LEFT_ALIGNMENT, RIGHT_ALIGNMENT, TOP_ALIGNMENT
 
Fields inherited from interface java.awt.image.ImageObserver
ABORT, ALLBITS, ERROR, FRAMEBITS, HEIGHT, PROPERTIES, SOMEBITS, WIDTH
 
Constructor Summary
Box(int axis)
          Creates a Box that displays its components along the the specified axis.
 
Method Summary
static Component createGlue()
          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).
static Box createHorizontalBox()
          Creates a Box that displays its components from left to right.
static Component createHorizontalGlue()
          Creates a horizontal glue component.
static Component createHorizontalStrut(int width)
          Creates an invisible, fixed-width component.
static Component createRigidArea(Dimension d)
          Creates an invisible component that's always the specified size.
static Box createVerticalBox()
          Creates a Box that displays its components from top to bottom.
static Component createVerticalGlue()
          Creates a vertical glue component.
static Component createVerticalStrut(int height)
          Creates an invisible, fixed-height component.
 AccessibleContext getAccessibleContext()
          Gets the AccessibleContext associated with this Box.
protected  void paintComponent(Graphics g)
          Paints this Box.
 void setLayout(LayoutManager l)
          Throws an AWTError, since a Box can use only a BoxLayout.
 
Methods inherited from class javax.swing.JComponent
addAncestorListener, addNotify, addVetoableChangeListener, computeVisibleRect, contains, createToolTip, disable, enable, firePropertyChange, firePropertyChange, firePropertyChange, fireVetoableChange, getActionForKeyStroke, getActionMap, getAlignmentX, getAlignmentY, getAncestorListeners, getAutoscrolls, getBaseline, getBaselineResizeBehavior, getBorder, getBounds, getClientProperty, getComponentGraphics, getComponentPopupMenu, getConditionForKeyStroke, getDebugGraphicsOptions, getDefaultLocale, getFontMetrics, getGraphics, getHeight, getInheritsPopupMenu, getInputMap, getInputMap, getInputVerifier, getInsets, getInsets, getListeners, getLocation, getMaximumSize, getMinimumSize, getNextFocusableComponent, getPopupLocation, getPreferredSize, getRegisteredKeyStrokes, getRootPane, getSize, getToolTipLocation, getToolTipText, getToolTipText, getTopLevelAncestor, getTransferHandler, getUIClassID, getVerifyInputWhenFocusTarget, getVetoableChangeListeners, getVisibleRect, getWidth, getX, getY, grabFocus, isDoubleBuffered, isLightweightComponent, isManagingFocus, isOpaque, isOptimizedDrawingEnabled, isPaintingForPrint, isPaintingTile, isRequestFocusEnabled, isValidateRoot, paint, paintBorder, paintChildren, paintImmediately, paintImmediately, paramString, print, printAll, printBorder, printChildren, printComponent, processComponentKeyEvent, processKeyBinding, processKeyEvent, processMouseEvent, processMouseMotionEvent, putClientProperty, registerKeyboardAction, registerKeyboardAction, removeAncestorListener, removeNotify, removeVetoableChangeListener, repaint, repaint, requestDefaultFocus, requestFocus, requestFocus, requestFocusInWindow, requestFocusInWindow, resetKeyboardActions, reshape, revalidate, scrollRectToVisible, setActionMap, setAlignmentX, setAlignmentY, setAutoscrolls, setBackground, setBorder, setComponentPopupMenu, setDebugGraphicsOptions, setDefaultLocale, setDoubleBuffered, setEnabled, setFocusTraversalKeys, setFont, setForeground, setInheritsPopupMenu, setInputMap, setInputVerifier, setMaximumSize, setMinimumSize, setNextFocusableComponent, setOpaque, setPreferredSize, setRequestFocusEnabled, setToolTipText, setTransferHandler, setUI, setVerifyInputWhenFocusTarget, setVisible, unregisterKeyboardAction, update, updateUI
 
Methods inherited from class java.awt.Container
add, add, add, add, add, addContainerListener, addImpl, addPropertyChangeListener, addPropertyChangeListener, applyComponentOrientation, areFocusTraversalKeysSet, countComponents, deliverEvent, doLayout, findComponentAt, findComponentAt, getComponent, getComponentAt, getComponentAt, getComponentCount, getComponents, getComponentZOrder, getContainerListeners, getFocusTraversalKeys, getFocusTraversalPolicy, getLayout, getMousePosition, insets, invalidate, isAncestorOf, isFocusCycleRoot, isFocusCycleRoot, isFocusTraversalPolicyProvider, isFocusTraversalPolicySet, layout, list, list, locate, minimumSize, paintComponents, preferredSize, printComponents, processContainerEvent, processEvent, remove, remove, removeAll, removeContainerListener, setComponentZOrder, setFocusCycleRoot, setFocusTraversalPolicy, setFocusTraversalPolicyProvider, transferFocusBackward, transferFocusDownCycle, validate, validateTree
 
Methods inherited from class java.awt.Component
action, add, addComponentListener, addFocusListener, addHierarchyBoundsListener, addHierarchyListener, addInputMethodListener, addKeyListener, addMouseListener, addMouseMotionListener, addMouseWheelListener, bounds, checkImage, checkImage, coalesceEvents, contains, createImage, createImage, createVolatileImage, createVolatileImage, disableEvents, dispatchEvent, enable, enableEvents, enableInputMethods, firePropertyChange, firePropertyChange, firePropertyChange, firePropertyChange, firePropertyChange, firePropertyChange, getBackground, getBounds, getColorModel, getComponentListeners, getComponentOrientation, getCursor, getDropTarget, getFocusCycleRootAncestor, getFocusListeners, getFocusTraversalKeysEnabled, getFont, getForeground, getGraphicsConfiguration, getHierarchyBoundsListeners, getHierarchyListeners, getIgnoreRepaint, getInputContext, getInputMethodListeners, getInputMethodRequests, getKeyListeners, getLocale, getLocation, getLocationOnScreen, getMouseListeners, getMouseMotionListeners, getMousePosition, getMouseWheelListeners, getName, getParent, getPeer, getPropertyChangeListeners, getPropertyChangeListeners, getSize, getToolkit, getTreeLock, gotFocus, handleEvent, hasFocus, hide, imageUpdate, inside, isBackgroundSet, isCursorSet, isDisplayable, isEnabled, isFocusable, isFocusOwner, isFocusTraversable, isFontSet, isForegroundSet, isLightweight, isMaximumSizeSet, isMinimumSizeSet, isPreferredSizeSet, isShowing, isValid, isVisible, keyDown, keyUp, list, list, list, location, lostFocus, mouseDown, mouseDrag, mouseEnter, mouseExit, mouseMove, mouseUp, move, nextFocus, paintAll, postEvent, prepareImage, prepareImage, processComponentEvent, processFocusEvent, processHierarchyBoundsEvent, processHierarchyEvent, processInputMethodEvent, processMouseWheelEvent, remove, removeComponentListener, removeFocusListener, removeHierarchyBoundsListener, removeHierarchyListener, removeInputMethodListener, removeKeyListener, removeMouseListener, removeMouseMotionListener, removeMouseWheelListener, removePropertyChangeListener, removePropertyChangeListener, repaint, repaint, repaint, resize, resize, setBounds, setBounds, setComponentOrientation, setCursor, setDropTarget, setFocusable, setFocusTraversalKeysEnabled, setIgnoreRepaint, setLocale, setLocation, setLocation, setName, setSize, setSize, show, show, size, toString, transferFocus, transferFocusUpCycle
 
Methods inherited from class java.lang.Object
clone, equals, finalize, getClass, hashCode, notify, notifyAll, wait, wait, wait
 

Constructor Detail

Box

public Box(int axis)
Creates a Box that displays its components along the the specified axis.

Parameters:
axis - can be BoxLayout.X_AXIS, BoxLayout.Y_AXIS, BoxLayout.LINE_AXIS or BoxLayout.PAGE_AXIS.
Throws:
AWTError - if the axis is invalid
See Also:
createHorizontalBox(), createVerticalBox()
Method Detail

createHorizontalBox

public static Box createHorizontalBox()
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

createVerticalBox

public static Box createVerticalBox()
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

createRigidArea

public static Component createRigidArea(Dimension d)
Creates an invisible component that's always the specified size.

Parameters:
d - the dimensions of the invisible component
Returns:
the component
See Also:
createGlue(), createHorizontalStrut(int), createVerticalStrut(int)

createHorizontalStrut

public static Component createHorizontalStrut(int width)
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.

Parameters:
width - the width of the invisible component, in pixels >= 0
Returns:
the component
See Also:
createVerticalStrut(int), createGlue(), createRigidArea(java.awt.Dimension)

createVerticalStrut

public static Component createVerticalStrut(int height)
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.

Parameters:
height - the height of the invisible component, in pixels >= 0
Returns:
the component
See Also:
createHorizontalStrut(int), createGlue(), createRigidArea(java.awt.Dimension)

createGlue

public static Component createGlue()
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

createHorizontalGlue

public static Component createHorizontalGlue()
Creates a horizontal glue component.

Returns:
the component

createVerticalGlue

public static Component createVerticalGlue()
Creates a vertical glue component.

Returns:
the component

setLayout

public void setLayout(LayoutManager l)
Throws an AWTError, since a Box can use only a BoxLayout.

Overrides:
setLayout in class Container
Parameters:
l - the layout manager to use
See Also:
Container.doLayout(), Container.getLayout()

paintComponent

protected void paintComponent(Graphics g)
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.

Overrides:
paintComponent in class JComponent
Parameters:
g - the Graphics to paint to
Throws:
NullPointerException - if g is null
Since:
1.6
See Also:
JComponent.paint(java.awt.Graphics), ComponentUI

getAccessibleContext

public AccessibleContext getAccessibleContext()
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.

Specified by:
getAccessibleContext in interface Accessible
Overrides:
getAccessibleContext in class JComponent
Returns:
an AccessibleBox that serves as the AccessibleContext of this Box

Java™ Platform
Standard Ed. 6

Submit a bug or feature
For further API reference and developer documentation, see Java SE Developer Documentation. That documentation contains more detailed, developer-targeted descriptions, with conceptual overviews, definitions of terms, workarounds, and working code examples.

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