javax.swing
Class JProgressBar

java.lang.Object
  |
  +--java.awt.Component
        |
        +--java.awt.Container
              |
              +--javax.swing.JComponent
                    |
                    +--javax.swing.JProgressBar

All Implemented Interfaces:

Accessible, ImageObserver, MenuContainer, Serializable, SwingConstants

public class JProgressBar

extends JComponent

implements SwingConstants, Accessible

A component that, by default, displays an integer value within a bounded interval. A progress bar typically communicates the progress of some work by displaying its percentage of completion and possibly a textual display of this percentage.

To indicate that a task of unknown length is executing, you can put a progress bar into indeterminate mode. While the bar is in indeterminate mode, it animates constantly to show that work is occurring. As soon as you can determine the task's length and amount of progress, you should update the progress bar's value and switch it back to determinate mode.

Here is an example of creating a progress bar, where task is an object that returns information about the progress of some work:

progressBar = new JProgressBar(0, task.getLengthOfTask());
progressBar.setValue(0);
progressBar.setStringPainted(true);

Here is an example of updating the value of the progress bar:

progressBar.setValue(task.getCurrent());

Here is an example of putting a progress bar into indeterminate mode, and then switching back to determinate mode once the length of the task is known:

progressBar = new JProgressBar();
...//when the task of (initially) unknown length begins:
progressBar.setIndeterminate(true);
...//do some work; get length of task...
progressBar.setMaximum(newLength);
progressBar.setValue(newValue);
progressBar.setIndeterminate(false);

For complete examples and further documentation see How to Monitor Progress, 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^TM has been added to the java.beans package. Please see XMLEncoder.

See Also:

BasicProgressBarUI

Nested Class Summary

protected class

JProgressBar.AccessibleJProgressBar This class implements accessibility support for the JProgressBar class.

Nested classes inherited from class javax.swing.JComponent

Nested classes inherited from class java.awt.Container

Nested classes inherited from class java.awt.Component

Component.BltBufferStrategy, Component.FlipBufferStrategy

Field Summary

protected ChangeEvent	changeEvent Only one ChangeEvent is needed per instance since the event's only interesting property is the immutable source, which is the progress bar.
protected ChangeListener	changeListener Listens for change events sent by the progress bar's model, redispatching them to change-event listeners registered upon this progress bar.
protected BoundedRangeModel	model The object that holds the data for the progress bar.
protected int	orientation Whether the progress bar is horizontal or vertical.
protected boolean	paintBorder Whether to display a border around the progress bar.
protected boolean	paintString Whether to textually display a string on the progress bar.
protected String	progressString An optional string that can be displayed on the progress bar.

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 javax.swing.SwingConstants

BOTTOM, CENTER, EAST, HORIZONTAL, LEADING, LEFT, NEXT, NORTH, NORTH_EAST, NORTH_WEST, PREVIOUS, RIGHT, SOUTH, SOUTH_EAST, SOUTH_WEST, TOP, TRAILING, VERTICAL, WEST

Fields inherited from interface java.awt.image.ImageObserver

ABORT, ALLBITS, ERROR, FRAMEBITS, HEIGHT, PROPERTIES, SOMEBITS, WIDTH

Constructor Summary

JProgressBar()
Creates a horizontal progress bar that displays a border but no progress string.

JProgressBar(BoundedRangeModel newModel)
Creates a horizontal progress bar that uses the specified model to hold the progress bar's data.

JProgressBar(int orient)
Creates a progress bar with the specified orientation, which can be either JProgressBar.VERTICAL or JProgressBar.HORIZONTAL.

JProgressBar(int min, int max)
Creates a horizontal progress bar with the specified minimum and maximum.

JProgressBar(int orient, int min, int max)
Creates a progress bar using the specified orientation, minimum, and maximum.

Method Summary

void	addChangeListener(ChangeListener l) Adds the specified ChangeListener to the progress bar.
protected ChangeListener	createChangeListener() Subclasses that want to handle change events from the model differently can override this to return an instance of a custom ChangeListener implementation.
protected void	fireStateChanged() Notifies all listeners that have registered interest in ChangeEvents.
AccessibleContext	getAccessibleContext() Gets the AccessibleContext associated with this JProgressBar.
ChangeListener[]	getChangeListeners() Returns an array of all the ChangeListeners added to this progress bar with addChangeListener.
int	getMaximum() Returns the progress bar's maximum value, which is stored in the progress bar's BoundedRangeModel.
int	getMinimum() Returns the progress bar's minimum value, which is stored in the progress bar's BoundedRangeModel.
BoundedRangeModel	getModel() Returns the data model used by this progress bar.
int	getOrientation() Returns JProgressBar.VERTICAL or JProgressBar.HORIZONTAL, depending on the orientation of the progress bar.
double	getPercentComplete() Returns the percent complete for the progress bar.
String	getString() Returns the current value of the progress string.
ProgressBarUI	getUI() Returns the look-and-feel object that renders this component.
String	getUIClassID() Returns the name of the look-and-feel class that renders this component.
int	getValue() Returns the progress bar's current value, which is stored in the progress bar's BoundedRangeModel.
boolean	isBorderPainted() Returns the borderPainted property.
boolean	isIndeterminate() Returns the value of the indeterminate property.
boolean	isStringPainted() Returns the value of the stringPainted property.
protected void	paintBorder(Graphics g) Paints the progress bar's border if the borderPainted property is true.
protected String	paramString() Returns a string representation of this JProgressBar.
void	removeChangeListener(ChangeListener l) Removes a ChangeListener from the progress bar.
void	setBorderPainted(boolean b) Sets the borderPainted property, which is true if the progress bar should paint its border.
void	setIndeterminate(boolean newValue) Sets the indeterminate property of the progress bar, which determines whether the progress bar is in determinate or indeterminate mode.
void	setMaximum(int n) Sets the progress bar's maximum value (stored in the progress bar's data model) to n.
void	setMinimum(int n) Sets the progress bar's minimum value (stored in the progress bar's data model) to n.
void	setModel(BoundedRangeModel newModel) Sets the data model used by the JProgressBar.
void	setOrientation(int newOrientation) Sets the progress bar's orientation to newOrientation, which must be JProgressBar.VERTICAL or JProgressBar.HORIZONTAL.
void	setString(String s) Sets the value of the progress string.
void	setStringPainted(boolean b) Sets the value of the stringPainted property, which determines whether the progress bar should render a progress string.
void	setUI(ProgressBarUI ui) Sets the look-and-feel object that renders this component.
void	setValue(int n) Sets the progress bar's current value (stored in the progress bar's data model) to n.
void	updateUI() Resets the UI property to a value from the current look and feel.

Methods inherited from class javax.swing.JComponent

addAncestorListener, addNotify, addPropertyChangeListener, addPropertyChangeListener, addVetoableChangeListener, computeVisibleRect, contains, createToolTip, disable, enable, firePropertyChange, firePropertyChange, firePropertyChange, firePropertyChange, firePropertyChange, firePropertyChange, firePropertyChange, firePropertyChange, firePropertyChange, fireVetoableChange, getActionForKeyStroke, getActionMap, getAlignmentX, getAlignmentY, getAncestorListeners, getAutoscrolls, getBorder, getBounds, getClientProperty, getComponentGraphics, getConditionForKeyStroke, getDebugGraphicsOptions, getDefaultLocale, getGraphics, getHeight, getInputMap, getInputMap, getInputVerifier, getInsets, getInsets, getListeners, getLocation, getMaximumSize, getMinimumSize, getNextFocusableComponent, getPreferredSize, getPropertyChangeListeners, getPropertyChangeListeners, getRegisteredKeyStrokes, getRootPane, getSize, getToolTipLocation, getToolTipText, getToolTipText, getTopLevelAncestor, getTransferHandler, getVerifyInputWhenFocusTarget, getVetoableChangeListeners, getVisibleRect, getWidth, getX, getY, grabFocus, isDoubleBuffered, isLightweightComponent, isManagingFocus, isMaximumSizeSet, isMinimumSizeSet, isOpaque, isOptimizedDrawingEnabled, isPaintingTile, isPreferredSizeSet, isRequestFocusEnabled, isValidateRoot, paint, paintChildren, paintComponent, paintImmediately, paintImmediately, print, printAll, printBorder, printChildren, printComponent, processComponentKeyEvent, processKeyBinding, processKeyEvent, processMouseMotionEvent, putClientProperty, registerKeyboardAction, registerKeyboardAction, removeAncestorListener, removeNotify, removePropertyChangeListener, removePropertyChangeListener, removeVetoableChangeListener, repaint, repaint, requestDefaultFocus, requestFocus, requestFocus, requestFocusInWindow, requestFocusInWindow, resetKeyboardActions, reshape, revalidate, scrollRectToVisible, setActionMap, setAlignmentX, setAlignmentY, setAutoscrolls, setBackground, setBorder, setDebugGraphicsOptions, setDefaultLocale, setDoubleBuffered, setEnabled, setFont, setForeground, setInputMap, setInputVerifier, setMaximumSize, setMinimumSize, setNextFocusableComponent, setOpaque, setPreferredSize, setRequestFocusEnabled, setToolTipText, setTransferHandler, setUI, setVerifyInputWhenFocusTarget, setVisible, unregisterKeyboardAction, update

Methods inherited from class java.awt.Container

add, add, add, add, add, addContainerListener, addImpl, applyComponentOrientation, areFocusTraversalKeysSet, countComponents, deliverEvent, doLayout, findComponentAt, findComponentAt, getComponent, getComponentAt, getComponentAt, getComponentCount, getComponents, getContainerListeners, getFocusTraversalKeys, getFocusTraversalPolicy, getLayout, insets, invalidate, isAncestorOf, isFocusCycleRoot, isFocusCycleRoot, isFocusTraversalPolicySet, layout, list, list, locate, minimumSize, paintComponents, preferredSize, printComponents, processContainerEvent, processEvent, remove, remove, removeAll, removeContainerListener, setFocusCycleRoot, setFocusTraversalKeys, setFocusTraversalPolicy, setLayout, 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, getBackground, getBounds, getColorModel, getComponentListeners, getComponentOrientation, getCursor, getDropTarget, getFocusCycleRootAncestor, getFocusListeners, getFocusTraversalKeysEnabled, getFont, getFontMetrics, getForeground, getGraphicsConfiguration, getHierarchyBoundsListeners, getHierarchyListeners, getIgnoreRepaint, getInputContext, getInputMethodListeners, getInputMethodRequests, getKeyListeners, getLocale, getLocation, getLocationOnScreen, getMouseListeners, getMouseMotionListeners, getMouseWheelListeners, getName, getParent, getPeer, getSize, getToolkit, getTreeLock, gotFocus, handleEvent, hasFocus, hide, imageUpdate, inside, isBackgroundSet, isCursorSet, isDisplayable, isEnabled, isFocusable, isFocusOwner, isFocusTraversable, isFontSet, isForegroundSet, isLightweight, 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, processMouseEvent, processMouseWheelEvent, remove, removeComponentListener, removeFocusListener, removeHierarchyBoundsListener, removeHierarchyListener, removeInputMethodListener, removeKeyListener, removeMouseListener, removeMouseMotionListener, removeMouseWheelListener, 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

Field Detail

orientation

protected int orientation

Whether the progress bar is horizontal or vertical. The default is HORIZONTAL.

See Also:

setOrientation(int)

paintBorder

protected boolean paintBorder

Whether to display a border around the progress bar. The default is true.

See Also:

setBorderPainted(boolean)

model

protected BoundedRangeModel model

The object that holds the data for the progress bar.

See Also:

setModel(javax.swing.BoundedRangeModel)

progressString

protected String progressString

An optional string that can be displayed on the progress bar. The default is null. Setting this to a non-null value does not imply that the string will be displayed.

See Also:

setString(java.lang.String)

paintString

protected boolean paintString

Whether to textually display a string on the progress bar. The default is false. Setting this to true causes a textual display of the progress to be rendered on the progress bar. If the progressString is null, the percentage of completion is displayed on the progress bar. Otherwise, the progressString is rendered on the progress bar.

See Also:

setStringPainted(boolean)

changeEvent

protected transient ChangeEvent changeEvent

Only one ChangeEvent is needed per instance since the event's only interesting property is the immutable source, which is the progress bar.

changeListener

protected ChangeListener changeListener

Listens for change events sent by the progress bar's model, redispatching them to change-event listeners registered upon this progress bar.

See Also:

createChangeListener()

Constructor Detail

JProgressBar

public JProgressBar()

Creates a horizontal progress bar that displays a border but no progress string. The initial and minimum values are 0, and the maximum is 100.

See Also:

setOrientation(int), setBorderPainted(boolean), setStringPainted(boolean), setString(java.lang.String), setIndeterminate(boolean)

JProgressBar

public JProgressBar(int orient)

Creates a progress bar with the specified orientation, which can be either JProgressBar.VERTICAL or JProgressBar.HORIZONTAL. By default, a border is painted but a progress string is not. The initial and minimum values are 0, and the maximum is 100.

Parameters:

orient - the desired orientation of the progress bar

See Also:

setOrientation(int), setBorderPainted(boolean), setStringPainted(boolean), setString(java.lang.String), setIndeterminate(boolean)

JProgressBar

public JProgressBar(int min,
                    int max)

Creates a horizontal progress bar with the specified minimum and maximum. Sets the initial value of the progress bar to the specified minimum. By default, a border is painted but a progress string is not. The BoundedRangeModel that holds the progress bar's data handles any issues that may arise from improperly setting the minimum, initial, and maximum values on the progress bar.

Parameters:

min - the minimum value of the progress bar

max - the maximum value of the progress bar

See Also:

BoundedRangeModel, setOrientation(int), setBorderPainted(boolean), setStringPainted(boolean), setString(java.lang.String), setIndeterminate(boolean)

JProgressBar

public JProgressBar(int orient,
                    int min,
                    int max)

Creates a progress bar using the specified orientation, minimum, and maximum. By default, a border is painted but a progress string is not. Sets the initial value of the progress bar to the specified minimum. The BoundedRangeModel that holds the progress bar's data handles any issues that may arise from improperly setting the minimum, initial, and maximum values on the progress bar.

Parameters:

orient - the desired orientation of the progress bar

min - the minimum value of the progress bar

max - the maximum value of the progress bar

See Also:

BoundedRangeModel, setOrientation(int), setBorderPainted(boolean), setStringPainted(boolean), setString(java.lang.String), setIndeterminate(boolean)

JProgressBar

public JProgressBar(BoundedRangeModel newModel)

Creates a horizontal progress bar that uses the specified model to hold the progress bar's data. By default, a border is painted but a progress string is not.

Parameters:

newModel - the data model for the progress bar

See Also:

setOrientation(int), setBorderPainted(boolean), setStringPainted(boolean), setString(java.lang.String), setIndeterminate(boolean)

Method Detail

getOrientation

public int getOrientation()

Returns JProgressBar.VERTICAL or JProgressBar.HORIZONTAL, depending on the orientation of the progress bar. The default orientation is HORIZONTAL.

Returns:

HORIZONTAL or VERTICAL

See Also:

setOrientation(int)

setOrientation

public void setOrientation(int newOrientation)

Sets the progress bar's orientation to newOrientation, which must be JProgressBar.VERTICAL or JProgressBar.HORIZONTAL. The default orientation is HORIZONTAL.

Parameters:

newOrientation - HORIZONTAL or VERTICAL

Throws:

IllegalArgumentException - if newOrientation is an illegal value

See Also:

getOrientation()

isStringPainted

public boolean isStringPainted()

Returns the value of the stringPainted property.

Returns:

the value of the stringPainted property

See Also:

setStringPainted(boolean), setString(java.lang.String)

setStringPainted

public void setStringPainted(boolean b)

Sets the value of the stringPainted property, which determines whether the progress bar should render a progress string. The default is false: no string is painted. Some look and feels might not support progress strings or might support them only when the progress bar is in determinate mode.

Parameters:

b - true if the progress bar should render a string

See Also:

isStringPainted(), setString(java.lang.String)

getString

public String getString()

Returns the current value of the progress string. If you are providing a custom progress string by overriding this method, make sure your implementation calls setString before calling super.getString.

Returns:

the value of the percent string

See Also:

setString(java.lang.String)

setString

public void setString(String s)

Sets the value of the progress string. By default, this string is null. If you have provided a custom progress string and want to revert to the built-in behavior, set the string back to null. If you are providing a custom progress string by overriding this method, make sure that you call setString before calling getString. The progress string is painted only if the isStringPainted method returns true.

Parameters:

s - the value of the percent string

See Also:

getString(), setStringPainted(boolean), isStringPainted()

getPercentComplete

public double getPercentComplete()

Returns the percent complete for the progress bar. Note that this number is between 0.0 and 1.0.

Returns:

the percent complete for this progress bar

isBorderPainted

public boolean isBorderPainted()

Returns the borderPainted property.

Returns:

the value of the borderPainted property

See Also:

setBorderPainted(boolean)

setBorderPainted

public void setBorderPainted(boolean b)

Sets the borderPainted property, which is true if the progress bar should paint its border. The default value for this property is true. Some look and feels might not implement painted borders; they will ignore this property.

Parameters:

b - true if the progress bar should paint its border; otherwise, false

See Also:

isBorderPainted()

paintBorder

protected void paintBorder(Graphics g)

Paints the progress bar's border if the borderPainted property is true.

Overrides:

paintBorder in class JComponent

Parameters:

g - the Graphics context within which to paint the border

See Also:

JComponent.paint(java.awt.Graphics), JComponent.setBorder(javax.swing.border.Border), isBorderPainted(), setBorderPainted(boolean)

getUI

public ProgressBarUI getUI()

Returns the look-and-feel object that renders this component.

Returns:

the ProgressBarUI object that renders this component

setUI

public void setUI(ProgressBarUI ui)

Sets the look-and-feel object that renders this component.

Parameters:

ui - a ProgressBarUI object

See Also:

UIDefaults.getUI(javax.swing.JComponent)

updateUI

public void updateUI()

Resets the UI property to a value from the current look and feel.

Overrides:

updateUI in class JComponent

See Also:

JComponent.updateUI()

getUIClassID

public String getUIClassID()

Returns the name of the look-and-feel class that renders this component.

Overrides:

getUIClassID in class JComponent

Returns:

the string "ProgressBarUI"

See Also:

JComponent.getUIClassID(), UIDefaults.getUI(javax.swing.JComponent)

createChangeListener

protected ChangeListener createChangeListener()

Subclasses that want to handle change events from the model differently can override this to return an instance of a custom ChangeListener implementation.

See Also:

changeListener, ChangeListener, BoundedRangeModel

addChangeListener

public void addChangeListener(ChangeListener l)

Adds the specified ChangeListener to the progress bar.

Parameters:

l - the ChangeListener to add

removeChangeListener

public void removeChangeListener(ChangeListener l)

Removes a ChangeListener from the progress bar.

Parameters:

l - the ChangeListener to remove

getChangeListeners

public ChangeListener[] getChangeListeners()

Returns an array of all the ChangeListeners added to this progress bar with addChangeListener.

Returns:

all of the ChangeListeners added or an empty array if no listeners have been added

Since:

1.4

fireStateChanged

protected void fireStateChanged()

Notifies all listeners that have registered interest in ChangeEvents. The event instance is created if necessary.

See Also:

EventListenerList

getModel

public BoundedRangeModel getModel()

Returns the data model used by this progress bar.

Returns:

the BoundedRangeModel currently in use

See Also:

BoundedRangeModel

setModel

public void setModel(BoundedRangeModel newModel)

Sets the data model used by the JProgressBar.

Parameters:

newModel - the BoundedRangeModel to use

getValue

public int getValue()

Returns the progress bar's current value, which is stored in the progress bar's BoundedRangeModel. The value is always between the minimum and maximum values, inclusive. By default, the value is initialized to be equal to the minimum value.

Returns:

the current value of the progress bar

See Also:

setValue(int), BoundedRangeModel.getValue()

getMinimum

public int getMinimum()

Returns the progress bar's minimum value, which is stored in the progress bar's BoundedRangeModel. By default, the minimum value is 0.

Returns:

the progress bar's minimum value

See Also:

setMinimum(int), BoundedRangeModel.getMinimum()

getMaximum

public int getMaximum()

Returns the progress bar's maximum value, which is stored in the progress bar's BoundedRangeModel. By default, the maximum value is 100.

Returns:

the progress bar's maximum value

See Also:

setMaximum(int), BoundedRangeModel.getMaximum()

setValue

public void setValue(int n)

Sets the progress bar's current value (stored in the progress bar's data model) to n. The data model (a BoundedRangeModel instance) handles any mathematical issues arising from assigning faulty values.

If the new value is different from the previous value, all change listeners are notified.

Parameters:

n - the new value

See Also:

getValue(), BoundedRangeModel.setValue(int)

setMinimum

public void setMinimum(int n)

Sets the progress bar's minimum value (stored in the progress bar's data model) to n. The data model (a BoundedRangeModel instance) handles any mathematical issues arising from assigning faulty values.

If the minimum value is different from the previous minimum, all change listeners are notified.

Parameters:

n - the new minimum

See Also:

getMinimum(), addChangeListener(javax.swing.event.ChangeListener), BoundedRangeModel.setMinimum(int)

setMaximum

public void setMaximum(int n)

Sets the progress bar's maximum value (stored in the progress bar's data model) to n. The underlying BoundedRangeModel handles any mathematical issues arising from assigning faulty values.

If the maximum value is different from the previous maximum, all change listeners are notified.

Parameters:

n - the new maximum

See Also:

getMaximum(), addChangeListener(javax.swing.event.ChangeListener), BoundedRangeModel.setMaximum(int)

setIndeterminate

public void setIndeterminate(boolean newValue)

Sets the indeterminate property of the progress bar, which determines whether the progress bar is in determinate or indeterminate mode. An indeterminate progress bar continuously displays animation indicating that an operation of unknown length is occurring. By default, this property is false. Some look and feels might not support indeterminate progress bars; they will ignore this property.

See How to Monitor Progress for examples of using indeterminate progress bars.

Parameters:

newValue - true if the progress bar should change to indeterminate mode; false if it should revert to normal.

Since:

1.4

See Also:

isIndeterminate(), BasicProgressBarUI

isIndeterminate

public boolean isIndeterminate()

Returns the value of the indeterminate property.

Returns:

the value of the indeterminate property

Since:

1.4

See Also:

setIndeterminate(boolean)

paramString

protected String paramString()

Returns a string representation of this JProgressBar. This method is intended to be used only for debugging purposes. The content and format of the returned string may vary between implementations. The returned string may be empty but may not be null.

Overrides:

paramString in class JComponent

Returns:

a string representation of this JProgressBar

getAccessibleContext

public AccessibleContext getAccessibleContext()

Gets the AccessibleContext associated with this JProgressBar. For progress bars, the AccessibleContext takes the form of an AccessibleJProgressBar. A new AccessibleJProgressBar instance is created if necessary.

Specified by:

getAccessibleContext in interface Accessible

Overrides:

getAccessibleContext in class JComponent

Returns:

an AccessibleJProgressBar that serves as the AccessibleContext of this JProgressBar