Class JViewport

javax.swing.JViewport

All Implemented Interfaces:: ImageObserver, MenuContainer, Serializable, Accessible

public class JViewport extends JComponent implements Accessible

The "viewport" or "porthole" through which you see the underlying information. When you scroll, what moves is the viewport. It is like peering through a camera's viewfinder. Moving the viewfinder upwards brings new things into view at the top of the picture and loses things that were at the bottom.

By default, JViewport is opaque. To change this, use the setOpaque method.

NOTE:We have implemented a faster scrolling algorithm that does not require a buffer to draw in. The algorithm works as follows:

The view and parent view are checked to see if they are JComponents, if they aren't, stop and repaint the whole viewport.
If the viewport is obscured by an ancestor, stop and repaint the whole viewport.
Compute the region that will become visible, if it is as big as the viewport, stop and repaint the whole view region.
Obtain the ancestor Window's graphics and do a copyArea on the scrolled region.
Message the view to repaint the newly visible region.
The next time paint is invoked on the viewport, if the clip region is smaller than the viewport size a timer is kicked off to repaint the whole region.

In general this approach is much faster. Compared to the backing store approach this avoids the overhead of maintaining an offscreen buffer and having to do two copyAreas. Compared to the non backing store case this approach will greatly reduce the painted region.

This approach can cause slower times than the backing store approach when the viewport is obscured by another window, or partially offscreen. When another window obscures the viewport the copyArea will copy garbage and a paint event will be generated by the system to inform us we need to paint the newly exposed region. The only way to handle this is to repaint the whole viewport, which can cause slower performance than the backing store case. In most applications very rarely will the user be scrolling while the viewport is obscured by another window or offscreen, so this optimization is usually worth the performance hit when obscured.

Warning: Swing is not thread safe. For more information see Swing's Threading Policy.

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.

Since:

1.2

See Also:

Nested Class Summary

Modifier and Type	Class	Description
`protected class`	`JViewport.AccessibleJViewport`	This class implements accessibility support for the `JViewport` class.
`protected class`	`JViewport.ViewListener`	A listener for the view.

Nested classes/interfaces declared in class JComponent

JComponent.AccessibleJComponent

Modifier and Type	Class	Description
`class`	`JComponent.AccessibleJComponent`	Inner class of JComponent used to provide default support for accessibility.

Nested classes/interfaces declared in class Container

Container.AccessibleAWTContainer

Modifier and Type	Class	Description
`protected class`	`Container.AccessibleAWTContainer`	Inner class of Container used to provide default support for accessibility.

Nested classes/interfaces declared in class Component

Component.AccessibleAWTComponent, Component.BaselineResizeBehavior, Component.BltBufferStrategy, Component.FlipBufferStrategy

Modifier and Type	Class	Description
`protected class`	`Component.AccessibleAWTComponent`	Inner class of Component used to provide default support for accessibility.
`static enum`	`Component.BaselineResizeBehavior`	Enumeration of the common ways the baseline of a component can change as the size changes.
`protected class`	`Component.BltBufferStrategy`	Inner class for blitting offscreen surfaces to a component.
`protected class`	`Component.FlipBufferStrategy`	Inner class for flipping buffers on a component.

Field Summary

Modifier and Type	Field	Description
`protected boolean`	`backingStore`	Deprecated. As of Java 2 platform v1.3
`static final int`	`BACKINGSTORE_SCROLL_MODE`	Draws viewport contents into an offscreen image.
`protected Image`	`backingStoreImage`	The view image used for a backing store.
`static final int`	`BLIT_SCROLL_MODE`	Use `graphics.copyArea` to implement scrolling.
`protected boolean`	`isViewSizeSet`	True when the viewport dimensions have been determined.
`protected Point`	`lastPaintPosition`	The last `viewPosition` that we've painted, so we know how much of the backing store image is valid.
`protected boolean`	`scrollUnderway`	The `scrollUnderway` flag is used for components like `JList`.
`static final int`	`SIMPLE_SCROLL_MODE`	This mode uses the very simple method of redrawing the entire contents of the scrollpane each time it is scrolled.

Fields declared in class JComponent

listenerList, TOOL_TIP_TEXT_KEY, ui, UNDEFINED_CONDITION, WHEN_ANCESTOR_OF_FOCUSED_COMPONENT, WHEN_FOCUSED, WHEN_IN_FOCUSED_WINDOW

Modifier and Type	Field	Description
`protected EventListenerList`	`listenerList`	A list of event listeners for this component.
`static final String`	`TOOL_TIP_TEXT_KEY`	The comment to display when the cursor is over the component, also known as a "value tip", "flyover help", or "flyover label".
`protected ComponentUI`	`ui`	The look and feel delegate for this component.
`static final int`	`UNDEFINED_CONDITION`	Constant used by some of the APIs to mean that no condition is defined.
`static final int`	`WHEN_ANCESTOR_OF_FOCUSED_COMPONENT`	Constant used for `registerKeyboardAction` that means that the command should be invoked when the receiving component is an ancestor of the focused component or is itself the focused component.
`static final int`	`WHEN_FOCUSED`	Constant used for `registerKeyboardAction` that means that the command should be invoked when the component has the focus.
`static final int`	`WHEN_IN_FOCUSED_WINDOW`	Constant used for `registerKeyboardAction` that means that the command should be invoked when the receiving component is in the window that has the focus or is itself the focused component.

Fields declared in class Component

accessibleContext, BOTTOM_ALIGNMENT, CENTER_ALIGNMENT, LEFT_ALIGNMENT, RIGHT_ALIGNMENT, TOP_ALIGNMENT

Modifier and Type	Field	Description
`protected AccessibleContext`	`accessibleContext`	The `AccessibleContext` associated with this `Component`.
`static final float`	`BOTTOM_ALIGNMENT`	Ease-of-use constant for `getAlignmentY`.
`static final float`	`CENTER_ALIGNMENT`	Ease-of-use constant for `getAlignmentY` and `getAlignmentX`.
`static final float`	`LEFT_ALIGNMENT`	Ease-of-use constant for `getAlignmentX`.
`static final float`	`RIGHT_ALIGNMENT`	Ease-of-use constant for `getAlignmentX`.
`static final float`	`TOP_ALIGNMENT`	Ease-of-use constant for `getAlignmentY()`.

Fields declared in interface ImageObserver

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

Modifier and Type	Field	Description
`static final int`	`ABORT`	This flag in the infoflags argument to imageUpdate indicates that an image which was being tracked asynchronously was aborted before production was complete.
`static final int`	`ALLBITS`	This flag in the infoflags argument to imageUpdate indicates that a static image which was previously drawn is now complete and can be drawn again in its final form.
`static final int`	`ERROR`	This flag in the infoflags argument to imageUpdate indicates that an image which was being tracked asynchronously has encountered an error.
`static final int`	`FRAMEBITS`	This flag in the infoflags argument to imageUpdate indicates that another complete frame of a multi-frame image which was previously drawn is now available to be drawn again.
`static final int`	`HEIGHT`	This flag in the infoflags argument to imageUpdate indicates that the height of the base image is now available and can be taken from the height argument to the imageUpdate callback method.
`static final int`	`PROPERTIES`	This flag in the infoflags argument to imageUpdate indicates that the properties of the image are now available.
`static final int`	`SOMEBITS`	This flag in the infoflags argument to imageUpdate indicates that more pixels needed for drawing a scaled variation of the image are available.
`static final int`	`WIDTH`	This flag in the infoflags argument to imageUpdate indicates that the width of the base image is now available and can be taken from the width argument to the imageUpdate callback method.

Constructor Summary

Constructor	Description
`JViewport()`	Creates a `JViewport`.

Method Summary

Modifier and Type	Method	Description
`void`	`addChangeListener(ChangeListener l)`	Adds a `ChangeListener` to the list that is notified each time the view's size, position, or the viewport's extent size has changed.
`protected void`	`addImpl(Component child, Object constraints, int index)`	Sets the `JViewport`'s one lightweight child, which can be `null`.
`protected boolean`	`computeBlit(int dx, int dy, Point blitFrom, Point blitTo, Dimension blitSize, Rectangle blitPaint)`	Computes the parameters for a blit where the backing store image currently contains `oldLoc` in the upper left hand corner and we're scrolling to `newLoc`.
`protected LayoutManager`	`createLayoutManager()`	Subclassers can override this to install a different layout manager (or `null`) in the constructor.
`protected JViewport.ViewListener`	`createViewListener()`	Creates a listener for the view.
`protected void`	`firePropertyChange(String propertyName, Object oldValue, Object newValue)`	Notifies listeners of a property change.
`protected void`	`fireStateChanged()`	Notifies all `ChangeListeners` when the views size, position, or the viewports extent size has changed.
`AccessibleContext`	`getAccessibleContext()`	Gets the AccessibleContext associated with this JViewport.
`ChangeListener[]`	`getChangeListeners()`	Returns an array of all the `ChangeListener`s added to this JViewport with addChangeListener().
`Dimension`	`getExtentSize()`	Returns the size of the visible part of the view in view coordinates.
`final Insets`	`getInsets()`	Returns the insets (border) dimensions as (0,0,0,0), since borders are not supported on a `JViewport`.
`final Insets`	`getInsets(Insets insets)`	Returns an `Insets` object containing this `JViewport`s inset values.
`int`	`getScrollMode()`	Returns the current scrolling mode.
`ViewportUI`	`getUI()`	Returns the L&F object that renders this component.
`String`	`getUIClassID()`	Returns a string that specifies the name of the L&F class that renders this component.
`Component`	`getView()`	Returns the `JViewport`'s one child or `null`.
`Point`	`getViewPosition()`	Returns the view coordinates that appear in the upper left hand corner of the viewport, or 0,0 if there's no view.
`Rectangle`	`getViewRect()`	Returns a rectangle whose origin is `getViewPosition` and size is `getExtentSize`.
`Dimension`	`getViewSize()`	If the view's size hasn't been explicitly set, return the preferred size, otherwise return the view's current size.
`boolean`	`isBackingStoreEnabled()`	Deprecated. As of Java 2 platform v1.3, replaced by `getScrollMode()`.
`boolean`	`isOptimizedDrawingEnabled()`	The `JViewport` overrides the default implementation of this method (in `JComponent`) to return false.
`protected boolean`	`isPaintingOrigin()`	Returns true if scroll mode is a `BACKINGSTORE_SCROLL_MODE` to cause painting to originate from `JViewport`, or one of its ancestors.
`void`	`paint(Graphics g)`	Depending on whether the `backingStore` is enabled, either paint the image through the backing store or paint just the recently exposed part, using the backing store to "blit" the remainder.
`protected String`	`paramString()`	Returns a string representation of this `JViewport`.
`void`	`remove(Component child)`	Removes the `Viewport`s one lightweight child.
`void`	`removeChangeListener(ChangeListener l)`	Removes a `ChangeListener` from the list that's notified each time the views size, position, or the viewports extent size has changed.
`void`	`repaint(long tm, int x, int y, int w, int h)`	Always repaint in the parents coordinate system to make sure only one paint is performed by the `RepaintManager`.
`void`	`reshape(int x, int y, int w, int h)`	Sets the bounds of this viewport.
`void`	`scrollRectToVisible(Rectangle contentRect)`	Scrolls the view so that `Rectangle` within the view becomes visible.
`void`	`setBackingStoreEnabled(boolean enabled)`	Deprecated. As of Java 2 platform v1.3, replaced by `setScrollMode()`.
`final void`	`setBorder(Border border)`	The viewport "scrolls" its child (called the "view") by the normal parent/child clipping (typically the view is moved in the opposite direction of the scroll).
`void`	`setExtentSize(Dimension newExtent)`	Sets the size of the visible part of the view using view coordinates.
`void`	`setScrollMode(int mode)`	Used to control the method of scrolling the viewport contents.
`void`	`setUI(ViewportUI ui)`	Sets the L&F object that renders this component.
`void`	`setView(Component view)`	Sets the `JViewport`'s one lightweight child (`view`), which can be `null`.
`void`	`setViewPosition(Point p)`	Sets the view coordinates that appear in the upper left hand corner of the viewport, does nothing if there's no view.
`void`	`setViewSize(Dimension newSize)`	Sets the size of the view.
`Dimension`	`toViewCoordinates(Dimension size)`	Converts a size in pixel coordinates to view coordinates.
`Point`	`toViewCoordinates(Point p)`	Converts a point in pixel coordinates to view coordinates.
`void`	`updateUI()`	Resets the UI property to a value from the current look and feel.

Methods declared in class JComponent

addAncestorListener, addNotify, addVetoableChangeListener, computeVisibleRect, contains, createToolTip, disable, enable, 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, getListeners, getLocation, getMaximumSize, getMinimumSize, getNextFocusableComponent, getPopupLocation, getPreferredSize, getRegisteredKeyStrokes, getRootPane, getSize, getToolTipLocation, getToolTipText, getToolTipText, getTopLevelAncestor, getTransferHandler, getVerifyInputWhenFocusTarget, getVetoableChangeListeners, getVisibleRect, getWidth, getX, getY, grabFocus, hide, isDoubleBuffered, isLightweightComponent, isManagingFocus, isOpaque, isPaintingForPrint, isPaintingTile, isRequestFocusEnabled, isValidateRoot, paintBorder, paintChildren, paintComponent, paintImmediately, paintImmediately, print, printAll, printBorder, printChildren, printComponent, processComponentKeyEvent, processKeyBinding, processKeyEvent, processMouseEvent, processMouseMotionEvent, putClientProperty, registerKeyboardAction, registerKeyboardAction, removeAncestorListener, removeNotify, removeVetoableChangeListener, repaint, requestDefaultFocus, requestFocus, requestFocus, requestFocusInWindow, requestFocusInWindow, resetKeyboardActions, revalidate, setActionMap, setAlignmentX, setAlignmentY, setAutoscrolls, setBackground, setComponentPopupMenu, setDebugGraphicsOptions, setDefaultLocale, setDoubleBuffered, setEnabled, setFocusTraversalKeys, setFont, setForeground, setInheritsPopupMenu, setInputMap, setInputVerifier, setMaximumSize, setMinimumSize, setNextFocusableComponent, setOpaque, setPreferredSize, setRequestFocusEnabled, setToolTipText, setTransferHandler, setUI, setVerifyInputWhenFocusTarget, setVisible, unregisterKeyboardAction, update

Modifier and Type	Method	Description
`void`	`addAncestorListener(AncestorListener listener)`	Registers `listener` so that it will receive `AncestorEvents` when it or any of its ancestors move or are made visible or invisible.
`void`	`addNotify()`	Notifies this component that it now has a parent component.
`void`	`addVetoableChangeListener(VetoableChangeListener listener)`	Adds a `VetoableChangeListener` to the listener list.
`void`	`computeVisibleRect(Rectangle visibleRect)`	Returns the `Component`'s "visible rect rectangle" - the intersection of the visible rectangles for this component and all of its ancestors.
`boolean`	`contains(int x, int y)`	Gives the UI delegate an opportunity to define the precise shape of this component for the sake of mouse processing.
`JToolTip`	`createToolTip()`	Returns the instance of `JToolTip` that should be used to display the tooltip.
`void`	`disable()`	Deprecated. As of JDK version 1.1, replaced by `java.awt.Component.setEnabled(boolean)`.
`void`	`enable()`	Deprecated. As of JDK version 1.1, replaced by `java.awt.Component.setEnabled(boolean)`.
`void`	`firePropertyChange(String propertyName, boolean oldValue, boolean newValue)`	Support for reporting bound property changes for boolean properties.
`void`	`firePropertyChange(String propertyName, int oldValue, int newValue)`	Support for reporting bound property changes for integer properties.
`protected void`	`fireVetoableChange(String propertyName, Object oldValue, Object newValue)`	Supports reporting constrained property changes.
`ActionListener`	`getActionForKeyStroke(KeyStroke aKeyStroke)`	Returns the object that will perform the action registered for a given keystroke.
`final ActionMap`	`getActionMap()`	Returns the `ActionMap` used to determine what `Action` to fire for particular `KeyStroke` binding.
`float`	`getAlignmentX()`	Overrides `Container.getAlignmentX` to return the horizontal alignment.
`float`	`getAlignmentY()`	Overrides `Container.getAlignmentY` to return the vertical alignment.
`AncestorListener[]`	`getAncestorListeners()`	Returns an array of all the ancestor listeners registered on this component.
`boolean`	`getAutoscrolls()`	Gets the `autoscrolls` property.
`int`	`getBaseline(int width, int height)`	Returns the baseline.
`Component.BaselineResizeBehavior`	`getBaselineResizeBehavior()`	Returns an enum indicating how the baseline of the component changes as the size changes.
`Border`	`getBorder()`	Returns the border of this component or `null` if no border is currently set.
`Rectangle`	`getBounds(Rectangle rv)`	Stores the bounds of this component into "return value" `rv` and returns `rv`.
`final Object`	`getClientProperty(Object key)`	Returns the value of the property with the specified key.
`protected Graphics`	`getComponentGraphics(Graphics g)`	Returns the graphics object used to paint this component.
`JPopupMenu`	`getComponentPopupMenu()`	Returns `JPopupMenu` that assigned for this component.
`int`	`getConditionForKeyStroke(KeyStroke aKeyStroke)`	Returns the condition that determines whether a registered action occurs in response to the specified keystroke.
`int`	`getDebugGraphicsOptions()`	Returns the state of graphics debugging.
`static Locale`	`getDefaultLocale()`	Returns the default locale used to initialize each JComponent's locale property upon creation.
`FontMetrics`	`getFontMetrics(Font font)`	Gets the `FontMetrics` for the specified `Font`.
`Graphics`	`getGraphics()`	Returns this component's graphics context, which lets you draw on a component.
`int`	`getHeight()`	Returns the current height of this component.
`boolean`	`getInheritsPopupMenu()`	Returns true if the JPopupMenu should be inherited from the parent.
`final InputMap`	`getInputMap()`	Returns the `InputMap` that is used when the component has focus.
`final InputMap`	`getInputMap(int condition)`	Returns the `InputMap` that is used during `condition`.
`InputVerifier`	`getInputVerifier()`	Returns the input verifier for this component.
`<T extends EventListener> T[]`	`getListeners(Class<T> listenerType)`	Returns an array of all the objects currently registered as `FooListener`s upon this `JComponent`.
`Point`	`getLocation(Point rv)`	Stores the x,y origin of this component into "return value" `rv` and returns `rv`.
`Dimension`	`getMaximumSize()`	If the maximum size has been set to a non-`null` value just returns it.
`Dimension`	`getMinimumSize()`	If the minimum size has been set to a non-`null` value just returns it.
`Component`	`getNextFocusableComponent()`	Deprecated. As of 1.4, replaced by `FocusTraversalPolicy`.
`Point`	`getPopupLocation(MouseEvent event)`	Returns the preferred location to display the popup menu in this component's coordinate system.
`Dimension`	`getPreferredSize()`	If the `preferredSize` has been set to a non-`null` value just returns it.
`KeyStroke[]`	`getRegisteredKeyStrokes()`	Returns the `KeyStrokes` that will initiate registered actions.
`JRootPane`	`getRootPane()`	Returns the `JRootPane` ancestor for this component.
`Dimension`	`getSize(Dimension rv)`	Stores the width/height of this component into "return value" `rv` and returns `rv`.
`Point`	`getToolTipLocation(MouseEvent event)`	Returns the tooltip location in this component's coordinate system.
`String`	`getToolTipText()`	Returns the tooltip string that has been set with `setToolTipText`.
`String`	`getToolTipText(MouseEvent event)`	Returns the string to be used as the tooltip for event.
`Container`	`getTopLevelAncestor()`	Returns the top-level ancestor of this component (the containing `Window`) or `null` if this component has not been added to any container.
`TransferHandler`	`getTransferHandler()`	Gets the `transferHandler` property.
`boolean`	`getVerifyInputWhenFocusTarget()`	Returns the value that indicates whether the input verifier for the current focus owner will be called before this component requests focus.
`VetoableChangeListener[]`	`getVetoableChangeListeners()`	Returns an array of all the vetoable change listeners registered on this component.
`Rectangle`	`getVisibleRect()`	Returns the `Component`'s "visible rectangle" - the intersection of this component's visible rectangle, `new Rectangle(0, 0, getWidth(), getHeight())`, and all of its ancestors' visible rectangles.
`int`	`getWidth()`	Returns the current width of this component.
`int`	`getX()`	Returns the current x coordinate of the component's origin.
`int`	`getY()`	Returns the current y coordinate of the component's origin.
`void`	`grabFocus()`	Requests that this Component get the input focus, and that this Component's top-level ancestor become the focused Window.
`void`	`hide()`	Deprecated.
`boolean`	`isDoubleBuffered()`	Returns whether this component should use a buffer to paint.
`static boolean`	`isLightweightComponent(Component c)`	Returns true if this component is lightweight, that is, if it doesn't have a native window system peer.
`boolean`	`isManagingFocus()`	Deprecated. As of 1.4, replaced by `Component.setFocusTraversalKeys(int, Set)` and `Container.setFocusCycleRoot(boolean)`.
`boolean`	`isOpaque()`	Returns true if this component is completely opaque.
`final boolean`	`isPaintingForPrint()`	Returns `true` if the current painting operation on this component is part of a `print` operation.
`boolean`	`isPaintingTile()`	Returns true if the component is currently painting a tile.
`boolean`	`isRequestFocusEnabled()`	Returns `true` if this `JComponent` should get focus; otherwise returns `false`.
`boolean`	`isValidateRoot()`	If this method returns true, `revalidate` calls by descendants of this component will cause the entire tree beginning with this root to be validated.
`protected void`	`paintBorder(Graphics g)`	Paints the component's border.
`protected void`	`paintChildren(Graphics g)`	Paints this component's children.
`protected void`	`paintComponent(Graphics g)`	Calls the UI delegate's paint method, if the UI delegate is non-`null`.
`void`	`paintImmediately(int x, int y, int w, int h)`	Paints the specified region in this component and all of its descendants that overlap the region, immediately.
`void`	`paintImmediately(Rectangle r)`	Paints the specified region now.
`void`	`print(Graphics g)`	Invoke this method to print the component to the specified `Graphics`.
`void`	`printAll(Graphics g)`	Invoke this method to print the component.
`protected void`	`printBorder(Graphics g)`	Prints the component's border.
`protected void`	`printChildren(Graphics g)`	Prints this component's children.
`protected void`	`printComponent(Graphics g)`	This is invoked during a printing operation.
`protected void`	`processComponentKeyEvent(KeyEvent e)`	Processes any key events that the component itself recognizes.
`protected boolean`	`processKeyBinding(KeyStroke ks, KeyEvent e, int condition, boolean pressed)`	Invoked to process the key bindings for `ks` as the result of the `KeyEvent` `e`.
`protected void`	`processKeyEvent(KeyEvent e)`	Overrides `processKeyEvent` to process events.
`protected void`	`processMouseEvent(MouseEvent e)`	Processes mouse events occurring on this component by dispatching them to any registered `MouseListener` objects, refer to `Component.processMouseEvent(MouseEvent)` for a complete description of this method.
`protected void`	`processMouseMotionEvent(MouseEvent e)`	Processes mouse motion events, such as MouseEvent.MOUSE_DRAGGED.
`final void`	`putClientProperty(Object key, Object value)`	Adds an arbitrary key/value "client property" to this component.
`void`	`registerKeyboardAction(ActionListener anAction, String aCommand, KeyStroke aKeyStroke, int aCondition)`	This method is now obsolete, please use a combination of `getActionMap()` and `getInputMap()` for similar behavior.
`void`	`registerKeyboardAction(ActionListener anAction, KeyStroke aKeyStroke, int aCondition)`	This method is now obsolete, please use a combination of `getActionMap()` and `getInputMap()` for similar behavior.
`void`	`removeAncestorListener(AncestorListener listener)`	Unregisters `listener` so that it will no longer receive `AncestorEvents`.
`void`	`removeNotify()`	Notifies this component that it no longer has a parent component.
`void`	`removeVetoableChangeListener(VetoableChangeListener listener)`	Removes a `VetoableChangeListener` from the listener list.
`void`	`repaint(Rectangle r)`	Adds the specified region to the dirty region list if the component is showing.
`boolean`	`requestDefaultFocus()`	Deprecated. As of 1.4, replaced by `FocusTraversalPolicy.getDefaultComponent(Container).requestFocus()`
`void`	`requestFocus()`	Requests that this `Component` gets the input focus.
`boolean`	`requestFocus(boolean temporary)`	Requests that this `Component` gets the input focus.
`boolean`	`requestFocusInWindow()`	Requests that this `Component` gets the input focus.
`protected boolean`	`requestFocusInWindow(boolean temporary)`	Requests that this `Component` gets the input focus.
`void`	`resetKeyboardActions()`	Unregisters all the bindings in the first tier `InputMaps` and `ActionMap`.
`void`	`revalidate()`	Supports deferred automatic layout.
`final void`	`setActionMap(ActionMap am)`	Sets the `ActionMap` to `am`.
`void`	`setAlignmentX(float alignmentX)`	Sets the horizontal alignment.
`void`	`setAlignmentY(float alignmentY)`	Sets the vertical alignment.
`void`	`setAutoscrolls(boolean autoscrolls)`	Sets the `autoscrolls` property.
`void`	`setBackground(Color bg)`	Sets the background color of this component.
`void`	`setComponentPopupMenu(JPopupMenu popup)`	Sets the `JPopupMenu` for this `JComponent`.
`void`	`setDebugGraphicsOptions(int debugOptions)`	Enables or disables diagnostic information about every graphics operation performed within the component or one of its children.
`static void`	`setDefaultLocale(Locale l)`	Sets the default locale used to initialize each JComponent's locale property upon creation.
`void`	`setDoubleBuffered(boolean aFlag)`	Sets whether this component should use a buffer to paint.
`void`	`setEnabled(boolean enabled)`	Sets whether or not this component is enabled.
`void`	`setFocusTraversalKeys(int id, Set<? extends AWTKeyStroke> keystrokes)`	Sets the focus traversal keys for a given traversal operation for this Component.
`void`	`setFont(Font font)`	Sets the font for this component.
`void`	`setForeground(Color fg)`	Sets the foreground color of this component.
`void`	`setInheritsPopupMenu(boolean value)`	Sets whether or not `getComponentPopupMenu` should delegate to the parent if this component does not have a `JPopupMenu` assigned to it.
`final void`	`setInputMap(int condition, InputMap map)`	Sets the `InputMap` to use under the condition `condition` to `map`.
`void`	`setInputVerifier(InputVerifier inputVerifier)`	Sets the input verifier for this component.
`void`	`setMaximumSize(Dimension maximumSize)`	Sets the maximum size of this component to a constant value.
`void`	`setMinimumSize(Dimension minimumSize)`	Sets the minimum size of this component to a constant value.
`void`	`setNextFocusableComponent(Component aComponent)`	Deprecated. As of 1.4, replaced by `FocusTraversalPolicy`
`void`	`setOpaque(boolean isOpaque)`	If true the component paints every pixel within its bounds.
`void`	`setPreferredSize(Dimension preferredSize)`	Sets the preferred size of this component.
`void`	`setRequestFocusEnabled(boolean requestFocusEnabled)`	Provides a hint as to whether or not this `JComponent` should get focus.
`void`	`setToolTipText(String text)`	Registers the text to display in a tool tip.
`void`	`setTransferHandler(TransferHandler newHandler)`	Sets the `TransferHandler`, which provides support for transfer of data into and out of this component via cut/copy/paste and drag and drop.
`protected void`	`setUI(ComponentUI newUI)`	Sets the look and feel delegate for this component.
`void`	`setVerifyInputWhenFocusTarget(boolean verifyInputWhenFocusTarget)`	Sets the value to indicate whether input verifier for the current focus owner will be called before this component requests focus.
`void`	`setVisible(boolean aFlag)`	Makes the component visible or invisible.
`void`	`unregisterKeyboardAction(KeyStroke aKeyStroke)`	This method is now obsolete.
`void`	`update(Graphics g)`	Calls `paint`.

Methods declared in class Container

add, add, add, add, add, addContainerListener, 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, removeAll, removeContainerListener, setComponentZOrder, setFocusCycleRoot, setFocusTraversalPolicy, setFocusTraversalPolicyProvider, setLayout, transferFocusDownCycle, validate, validateTree

Modifier and Type	Method	Description
`Component`	`add(Component comp)`	Appends the specified component to the end of this container.
`Component`	`add(Component comp, int index)`	Adds the specified component to this container at the given position.
`void`	`add(Component comp, Object constraints)`	Adds the specified component to the end of this container.
`void`	`add(Component comp, Object constraints, int index)`	Adds the specified component to this container with the specified constraints at the specified index.
`Component`	`add(String name, Component comp)`	Adds the specified component to this container.
`void`	`addContainerListener(ContainerListener l)`	Adds the specified container listener to receive container events from this container.
`void`	`addPropertyChangeListener(PropertyChangeListener listener)`	Adds a PropertyChangeListener to the listener list.
`void`	`addPropertyChangeListener(String propertyName, PropertyChangeListener listener)`	Adds a PropertyChangeListener to the listener list for a specific property.
`void`	`applyComponentOrientation(ComponentOrientation o)`	Sets the `ComponentOrientation` property of this container and all components contained within it.
`boolean`	`areFocusTraversalKeysSet(int id)`	Returns whether the Set of focus traversal keys for the given focus traversal operation has been explicitly defined for this Container.
`int`	`countComponents()`	Deprecated. As of JDK version 1.1, replaced by getComponentCount().
`void`	`deliverEvent(Event e)`	Deprecated. As of JDK version 1.1, replaced by `dispatchEvent(AWTEvent e)`
`void`	`doLayout()`	Causes this container to lay out its components.
`Component`	`findComponentAt(int x, int y)`	Locates the visible child component that contains the specified position.
`Component`	`findComponentAt(Point p)`	Locates the visible child component that contains the specified point.
`Component`	`getComponent(int n)`	Gets the nth component in this container.
`Component`	`getComponentAt(int x, int y)`	Locates the component that contains the x,y position.
`Component`	`getComponentAt(Point p)`	Gets the component that contains the specified point.
`int`	`getComponentCount()`	Gets the number of components in this panel.
`Component[]`	`getComponents()`	Gets all the components in this container.
`int`	`getComponentZOrder(Component comp)`	Returns the z-order index of the component inside the container.
`ContainerListener[]`	`getContainerListeners()`	Returns an array of all the container listeners registered on this container.
`Set<AWTKeyStroke>`	`getFocusTraversalKeys(int id)`	Returns the Set of focus traversal keys for a given traversal operation for this Container.
`FocusTraversalPolicy`	`getFocusTraversalPolicy()`	Returns the focus traversal policy that will manage keyboard traversal of this Container's children, or null if this Container is not a focus cycle root.
`LayoutManager`	`getLayout()`	Gets the layout manager for this container.
`Point`	`getMousePosition(boolean allowChildren)`	Returns the position of the mouse pointer in this `Container`'s coordinate space if the `Container` is under the mouse pointer, otherwise returns `null`.
`Insets`	`insets()`	Deprecated. As of JDK version 1.1, replaced by `getInsets()`.
`void`	`invalidate()`	Invalidates the container.
`boolean`	`isAncestorOf(Component c)`	Checks if the component is contained in the component hierarchy of this container.
`boolean`	`isFocusCycleRoot()`	Returns whether this Container is the root of a focus traversal cycle.
`boolean`	`isFocusCycleRoot(Container container)`	Returns whether the specified Container is the focus cycle root of this Container's focus traversal cycle.
`final boolean`	`isFocusTraversalPolicyProvider()`	Returns whether this container provides focus traversal policy.
`boolean`	`isFocusTraversalPolicySet()`	Returns whether the focus traversal policy has been explicitly set for this Container.
`void`	`layout()`	Deprecated. As of JDK version 1.1, replaced by `doLayout()`.
`void`	`list(PrintStream out, int indent)`	Prints a listing of this container to the specified output stream.
`void`	`list(PrintWriter out, int indent)`	Prints out a list, starting at the specified indentation, to the specified print writer.
`Component`	`locate(int x, int y)`	Deprecated. As of JDK version 1.1, replaced by `getComponentAt(int, int)`.
`Dimension`	`minimumSize()`	Deprecated. As of JDK version 1.1, replaced by `getMinimumSize()`.
`void`	`paintComponents(Graphics g)`	Paints each of the components in this container.
`Dimension`	`preferredSize()`	Deprecated. As of JDK version 1.1, replaced by `getPreferredSize()`.
`void`	`printComponents(Graphics g)`	Prints each of the components in this container.
`protected void`	`processContainerEvent(ContainerEvent e)`	Processes container events occurring on this container by dispatching them to any registered ContainerListener objects.
`protected void`	`processEvent(AWTEvent e)`	Processes events on this container.
`void`	`remove(int index)`	Removes the component, specified by `index`, from this container.
`void`	`removeAll()`	Removes all the components from this container.
`void`	`removeContainerListener(ContainerListener l)`	Removes the specified container listener so it no longer receives container events from this container.
`void`	`setComponentZOrder(Component comp, int index)`	Moves the specified component to the specified z-order index in the container.
`void`	`setFocusCycleRoot(boolean focusCycleRoot)`	Sets whether this Container is the root of a focus traversal cycle.
`void`	`setFocusTraversalPolicy(FocusTraversalPolicy policy)`	Sets the focus traversal policy that will manage keyboard traversal of this Container's children, if this Container is a focus cycle root.
`final void`	`setFocusTraversalPolicyProvider(boolean provider)`	Sets whether this container will be used to provide focus traversal policy.
`void`	`setLayout(LayoutManager mgr)`	Sets the layout manager for this container.
`void`	`transferFocusDownCycle()`	Transfers the focus down one focus traversal cycle.
`void`	`validate()`	Validates this container and all of its subcomponents.
`protected void`	`validateTree()`	Recursively descends the container tree and recomputes the layout for any subtrees marked as needing it (those marked as invalid).

Methods declared in class 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, getPropertyChangeListeners, getPropertyChangeListeners, getSize, getToolkit, getTreeLock, gotFocus, handleEvent, hasFocus, 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, requestFocus, requestFocus, requestFocusInWindow, resize, resize, setBounds, setBounds, setComponentOrientation, setCursor, setDropTarget, setFocusable, setFocusTraversalKeysEnabled, setIgnoreRepaint, setLocale, setLocation, setLocation, setMixingCutoutShape, setName, setSize, setSize, show, show, size, toString, transferFocus, transferFocusBackward, transferFocusUpCycle

Modifier and Type	Method	Description
`boolean`	`action(Event evt, Object what)`	Deprecated. As of JDK version 1.1, should register this component as ActionListener on component which fires action events.
`void`	`add(PopupMenu popup)`	Adds the specified popup menu to the component.
`void`	`addComponentListener(ComponentListener l)`	Adds the specified component listener to receive component events from this component.
`void`	`addFocusListener(FocusListener l)`	Adds the specified focus listener to receive focus events from this component when this component gains input focus.
`void`	`addHierarchyBoundsListener(HierarchyBoundsListener l)`	Adds the specified hierarchy bounds listener to receive hierarchy bounds events from this component when the hierarchy to which this container belongs changes.
`void`	`addHierarchyListener(HierarchyListener l)`	Adds the specified hierarchy listener to receive hierarchy changed events from this component when the hierarchy to which this container belongs changes.
`void`	`addInputMethodListener(InputMethodListener l)`	Adds the specified input method listener to receive input method events from this component.
`void`	`addKeyListener(KeyListener l)`	Adds the specified key listener to receive key events from this component.
`void`	`addMouseListener(MouseListener l)`	Adds the specified mouse listener to receive mouse events from this component.
`void`	`addMouseMotionListener(MouseMotionListener l)`	Adds the specified mouse motion listener to receive mouse motion events from this component.
`void`	`addMouseWheelListener(MouseWheelListener l)`	Adds the specified mouse wheel listener to receive mouse wheel events from this component.
`Rectangle`	`bounds()`	Deprecated. As of JDK version 1.1, replaced by `getBounds()`.
`int`	`checkImage(Image image, int width, int height, ImageObserver observer)`	Returns the status of the construction of a screen representation of the specified image.
`int`	`checkImage(Image image, ImageObserver observer)`	Returns the status of the construction of a screen representation of the specified image.
`protected AWTEvent`	`coalesceEvents(AWTEvent existingEvent, AWTEvent newEvent)`	Potentially coalesce an event being posted with an existing event.
`boolean`	`contains(Point p)`	Checks whether this component "contains" the specified point, where the point's x and y coordinates are defined to be relative to the coordinate system of this component.
`Image`	`createImage(int width, int height)`	Creates an off-screen drawable image to be used for double buffering.
`Image`	`createImage(ImageProducer producer)`	Creates an image from the specified image producer.
`VolatileImage`	`createVolatileImage(int width, int height)`	Creates a volatile off-screen drawable image to be used for double buffering.
`VolatileImage`	`createVolatileImage(int width, int height, ImageCapabilities caps)`	Creates a volatile off-screen drawable image, with the given capabilities.
`protected final void`	`disableEvents(long eventsToDisable)`	Disables the events defined by the specified event mask parameter from being delivered to this component.
`final void`	`dispatchEvent(AWTEvent e)`	Dispatches an event to this component or one of its sub components.
`void`	`enable(boolean b)`	Deprecated. As of JDK version 1.1, replaced by `setEnabled(boolean)`.
`protected final void`	`enableEvents(long eventsToEnable)`	Enables the events defined by the specified event mask parameter to be delivered to this component.
`void`	`enableInputMethods(boolean enable)`	Enables or disables input method support for this component.
`void`	`firePropertyChange(String propertyName, byte oldValue, byte newValue)`	Reports a bound property change.
`void`	`firePropertyChange(String propertyName, char oldValue, char newValue)`	Reports a bound property change.
`void`	`firePropertyChange(String propertyName, double oldValue, double newValue)`	Reports a bound property change.
`void`	`firePropertyChange(String propertyName, float oldValue, float newValue)`	Reports a bound property change.
`void`	`firePropertyChange(String propertyName, long oldValue, long newValue)`	Reports a bound property change.
`void`	`firePropertyChange(String propertyName, short oldValue, short newValue)`	Reports a bound property change.
`Color`	`getBackground()`	Gets the background color of this component.
`Rectangle`	`getBounds()`	Gets the bounds of this component in the form of a `Rectangle` object.
`ColorModel`	`getColorModel()`	Gets the instance of `ColorModel` used to display the component on the output device.
`ComponentListener[]`	`getComponentListeners()`	Returns an array of all the component listeners registered on this component.
`ComponentOrientation`	`getComponentOrientation()`	Retrieves the language-sensitive orientation that is to be used to order the elements or text within this component.
`Cursor`	`getCursor()`	Gets the cursor set in the component.
`DropTarget`	`getDropTarget()`	Gets the `DropTarget` associated with this `Component`.
`Container`	`getFocusCycleRootAncestor()`	Returns the Container which is the focus cycle root of this Component's focus traversal cycle.
`FocusListener[]`	`getFocusListeners()`	Returns an array of all the focus listeners registered on this component.
`boolean`	`getFocusTraversalKeysEnabled()`	Returns whether focus traversal keys are enabled for this Component.
`Font`	`getFont()`	Gets the font of this component.
`Color`	`getForeground()`	Gets the foreground color of this component.
`GraphicsConfiguration`	`getGraphicsConfiguration()`	Gets the `GraphicsConfiguration` associated with this `Component`.
`HierarchyBoundsListener[]`	`getHierarchyBoundsListeners()`	Returns an array of all the hierarchy bounds listeners registered on this component.
`HierarchyListener[]`	`getHierarchyListeners()`	Returns an array of all the hierarchy listeners registered on this component.
`boolean`	`getIgnoreRepaint()`	Returns whether or not paint messages received from the operating system should be ignored.
`InputContext`	`getInputContext()`	Gets the input context used by this component for handling the communication with input methods when text is entered in this component.
`InputMethodListener[]`	`getInputMethodListeners()`	Returns an array of all the input method listeners registered on this component.
`InputMethodRequests`	`getInputMethodRequests()`	Gets the input method request handler which supports requests from input methods for this component.
`KeyListener[]`	`getKeyListeners()`	Returns an array of all the key listeners registered on this component.
`Locale`	`getLocale()`	Gets the locale of this component.
`Point`	`getLocation()`	Gets the location of this component in the form of a point specifying the component's top-left corner.
`Point`	`getLocationOnScreen()`	Gets the location of this component in the form of a point specifying the component's top-left corner in the screen's coordinate space.
`MouseListener[]`	`getMouseListeners()`	Returns an array of all the mouse listeners registered on this component.
`MouseMotionListener[]`	`getMouseMotionListeners()`	Returns an array of all the mouse motion listeners registered on this component.
`Point`	`getMousePosition()`	Returns the position of the mouse pointer in this `Component`'s coordinate space if the `Component` is directly under the mouse pointer, otherwise returns `null`.
`MouseWheelListener[]`	`getMouseWheelListeners()`	Returns an array of all the mouse wheel listeners registered on this component.
`String`	`getName()`	Gets the name of the component.
`Container`	`getParent()`	Gets the parent of this component.
`PropertyChangeListener[]`	`getPropertyChangeListeners()`	Returns an array of all the property change listeners registered on this component.
`PropertyChangeListener[]`	`getPropertyChangeListeners(String propertyName)`	Returns an array of all the listeners which have been associated with the named property.
`Dimension`	`getSize()`	Returns the size of this component in the form of a `Dimension` object.
`Toolkit`	`getToolkit()`	Gets the toolkit of this component.
`final Object`	`getTreeLock()`	Gets this component's locking object (the object that owns the thread synchronization monitor) for AWT component-tree and layout operations.
`boolean`	`gotFocus(Event evt, Object what)`	Deprecated. As of JDK version 1.1, replaced by processFocusEvent(FocusEvent).
`boolean`	`handleEvent(Event evt)`	Deprecated. As of JDK version 1.1 replaced by processEvent(AWTEvent).
`boolean`	`hasFocus()`	Returns `true` if this `Component` is the focus owner.
`boolean`	`imageUpdate(Image img, int infoflags, int x, int y, int w, int h)`	Repaints the component when the image has changed.
`boolean`	`inside(int x, int y)`	Deprecated. As of JDK version 1.1, replaced by contains(int, int).
`boolean`	`isBackgroundSet()`	Returns whether the background color has been explicitly set for this Component.
`boolean`	`isCursorSet()`	Returns whether the cursor has been explicitly set for this Component.
`boolean`	`isDisplayable()`	Determines whether this component is displayable.
`boolean`	`isEnabled()`	Determines whether this component is enabled.
`boolean`	`isFocusable()`	Returns whether this Component can be focused.
`boolean`	`isFocusOwner()`	Returns `true` if this `Component` is the focus owner.
`boolean`	`isFocusTraversable()`	Deprecated. As of 1.4, replaced by `isFocusable()`.
`boolean`	`isFontSet()`	Returns whether the font has been explicitly set for this Component.
`boolean`	`isForegroundSet()`	Returns whether the foreground color has been explicitly set for this Component.
`boolean`	`isLightweight()`	A lightweight component doesn't have a native toolkit peer.
`boolean`	`isMaximumSizeSet()`	Returns true if the maximum size has been set to a non-`null` value otherwise returns false.
`boolean`	`isMinimumSizeSet()`	Returns whether or not `setMinimumSize` has been invoked with a non-null value.
`boolean`	`isPreferredSizeSet()`	Returns true if the preferred size has been set to a non-`null` value otherwise returns false.
`boolean`	`isShowing()`	Determines whether this component is showing on screen.
`boolean`	`isValid()`	Determines whether this component is valid.
`boolean`	`isVisible()`	Determines whether this component should be visible when its parent is visible.
`boolean`	`keyDown(Event evt, int key)`	Deprecated. As of JDK version 1.1, replaced by processKeyEvent(KeyEvent).
`boolean`	`keyUp(Event evt, int key)`	Deprecated. As of JDK version 1.1, replaced by processKeyEvent(KeyEvent).
`void`	`list()`	Prints a listing of this component to the standard system output stream `System.out`.
`void`	`list(PrintStream out)`	Prints a listing of this component to the specified output stream.
`void`	`list(PrintWriter out)`	Prints a listing to the specified print writer.
`Point`	`location()`	Deprecated. As of JDK version 1.1, replaced by `getLocation()`.
`boolean`	`lostFocus(Event evt, Object what)`	Deprecated. As of JDK version 1.1, replaced by processFocusEvent(FocusEvent).
`boolean`	`mouseDown(Event evt, int x, int y)`	Deprecated. As of JDK version 1.1, replaced by processMouseEvent(MouseEvent).
`boolean`	`mouseDrag(Event evt, int x, int y)`	Deprecated. As of JDK version 1.1, replaced by processMouseMotionEvent(MouseEvent).
`boolean`	`mouseEnter(Event evt, int x, int y)`	Deprecated. As of JDK version 1.1, replaced by processMouseEvent(MouseEvent).
`boolean`	`mouseExit(Event evt, int x, int y)`	Deprecated. As of JDK version 1.1, replaced by processMouseEvent(MouseEvent).
`boolean`	`mouseMove(Event evt, int x, int y)`	Deprecated. As of JDK version 1.1, replaced by processMouseMotionEvent(MouseEvent).
`boolean`	`mouseUp(Event evt, int x, int y)`	Deprecated. As of JDK version 1.1, replaced by processMouseEvent(MouseEvent).
`void`	`move(int x, int y)`	Deprecated. As of JDK version 1.1, replaced by `setLocation(int, int)`.
`void`	`nextFocus()`	Deprecated. As of JDK version 1.1, replaced by transferFocus().
`void`	`paintAll(Graphics g)`	Paints this component and all of its subcomponents.
`boolean`	`postEvent(Event e)`	Deprecated. As of JDK version 1.1, replaced by dispatchEvent(AWTEvent).
`boolean`	`prepareImage(Image image, int width, int height, ImageObserver observer)`	Prepares an image for rendering on this component at the specified width and height.
`boolean`	`prepareImage(Image image, ImageObserver observer)`	Prepares an image for rendering on this component.
`protected void`	`processComponentEvent(ComponentEvent e)`	Processes component events occurring on this component by dispatching them to any registered `ComponentListener` objects.
`protected void`	`processFocusEvent(FocusEvent e)`	Processes focus events occurring on this component by dispatching them to any registered `FocusListener` objects.
`protected void`	`processHierarchyBoundsEvent(HierarchyEvent e)`	Processes hierarchy bounds events occurring on this component by dispatching them to any registered `HierarchyBoundsListener` objects.
`protected void`	`processHierarchyEvent(HierarchyEvent e)`	Processes hierarchy events occurring on this component by dispatching them to any registered `HierarchyListener` objects.
`protected void`	`processInputMethodEvent(InputMethodEvent e)`	Processes input method events occurring on this component by dispatching them to any registered `InputMethodListener` objects.
`protected void`	`processMouseWheelEvent(MouseWheelEvent e)`	Processes mouse wheel events occurring on this component by dispatching them to any registered `MouseWheelListener` objects.
`void`	`remove(MenuComponent popup)`	Removes the specified popup menu from the component.
`void`	`removeComponentListener(ComponentListener l)`	Removes the specified component listener so that it no longer receives component events from this component.
`void`	`removeFocusListener(FocusListener l)`	Removes the specified focus listener so that it no longer receives focus events from this component.
`void`	`removeHierarchyBoundsListener(HierarchyBoundsListener l)`	Removes the specified hierarchy bounds listener so that it no longer receives hierarchy bounds events from this component.
`void`	`removeHierarchyListener(HierarchyListener l)`	Removes the specified hierarchy listener so that it no longer receives hierarchy changed events from this component.
`void`	`removeInputMethodListener(InputMethodListener l)`	Removes the specified input method listener so that it no longer receives input method events from this component.
`void`	`removeKeyListener(KeyListener l)`	Removes the specified key listener so that it no longer receives key events from this component.
`void`	`removeMouseListener(MouseListener l)`	Removes the specified mouse listener so that it no longer receives mouse events from this component.
`void`	`removeMouseMotionListener(MouseMotionListener l)`	Removes the specified mouse motion listener so that it no longer receives mouse motion events from this component.
`void`	`removeMouseWheelListener(MouseWheelListener l)`	Removes the specified mouse wheel listener so that it no longer receives mouse wheel events from this component.
`void`	`removePropertyChangeListener(PropertyChangeListener listener)`	Removes a PropertyChangeListener from the listener list.
`void`	`removePropertyChangeListener(String propertyName, PropertyChangeListener listener)`	Removes a `PropertyChangeListener` from the listener list for a specific property.
`void`	`repaint()`	Repaints this component.
`void`	`repaint(int x, int y, int width, int height)`	Repaints the specified rectangle of this component.
`void`	`repaint(long tm)`	Repaints the component.
`protected boolean`	`requestFocus(boolean temporary, FocusEvent.Cause cause)`	Requests by the reason of `cause` that this `Component` get the input focus, and that this `Component`'s top-level ancestor become the focused `Window`.
`void`	`requestFocus(FocusEvent.Cause cause)`	Requests by the reason of `cause` that this Component get the input focus, and that this Component's top-level ancestor become the focused Window.
`boolean`	`requestFocusInWindow(FocusEvent.Cause cause)`	Requests by the reason of `cause` that this Component get the input focus, if this Component's top-level ancestor is already the focused Window.
`void`	`resize(int width, int height)`	Deprecated. As of JDK version 1.1, replaced by `setSize(int, int)`.
`void`	`resize(Dimension d)`	Deprecated. As of JDK version 1.1, replaced by `setSize(Dimension)`.
`void`	`setBounds(int x, int y, int width, int height)`	Moves and resizes this component.
`void`	`setBounds(Rectangle r)`	Moves and resizes this component to conform to the new bounding rectangle `r`.
`void`	`setComponentOrientation(ComponentOrientation o)`	Sets the language-sensitive orientation that is to be used to order the elements or text within this component.
`void`	`setCursor(Cursor cursor)`	Sets the cursor image to the specified cursor.
`void`	`setDropTarget(DropTarget dt)`	Associate a `DropTarget` with this component.
`void`	`setFocusable(boolean focusable)`	Sets the focusable state of this Component to the specified value.
`void`	`setFocusTraversalKeysEnabled(boolean focusTraversalKeysEnabled)`	Sets whether focus traversal keys are enabled for this Component.
`void`	`setIgnoreRepaint(boolean ignoreRepaint)`	Sets whether or not paint messages received from the operating system should be ignored.
`void`	`setLocale(Locale l)`	Sets the locale of this component.
`void`	`setLocation(int x, int y)`	Moves this component to a new location.
`void`	`setLocation(Point p)`	Moves this component to a new location.
`void`	`setMixingCutoutShape(Shape shape)`	Sets a 'mixing-cutout' shape for this lightweight component.
`void`	`setName(String name)`	Sets the name of the component to the specified string.
`void`	`setSize(int width, int height)`	Resizes this component so that it has width `width` and height `height`.
`void`	`setSize(Dimension d)`	Resizes this component so that it has width `d.width` and height `d.height`.
`void`	`show()`	Deprecated. As of JDK version 1.1, replaced by `setVisible(boolean)`.
`void`	`show(boolean b)`	Deprecated. As of JDK version 1.1, replaced by `setVisible(boolean)`.
`Dimension`	`size()`	Deprecated. As of JDK version 1.1, replaced by `getSize()`.
`String`	`toString()`	Returns a string representation of this component and its values.
`void`	`transferFocus()`	Transfers the focus to the next component, as though this Component were the focus owner.
`void`	`transferFocusBackward()`	Transfers the focus to the previous component, as though this Component were the focus owner.
`void`	`transferFocusUpCycle()`	Transfers the focus up one focus traversal cycle.

Methods declared in class Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, wait, wait, wait

Modifier and Type	Method	Description
`protected Object`	`clone()`	Creates and returns a copy of this object.
`boolean`	`equals(Object obj)`	Indicates whether some other object is "equal to" this one.
`protected void`	`finalize()`	Deprecated, for removal: This API element is subject to removal in a future version. Finalization is deprecated and subject to removal in a future release.
`final Class<?>`	`getClass()`	Returns the runtime class of this `Object`.
`int`	`hashCode()`	Returns a hash code value for this object.
`final void`	`notify()`	Wakes up a single thread that is waiting on this object's monitor.
`final void`	`notifyAll()`	Wakes up all threads that are waiting on this object's monitor.
`final void`	`wait()`	Causes the current thread to wait until it is awakened, typically by being notified or interrupted.
`final void`	`wait(long timeoutMillis)`	Causes the current thread to wait until it is awakened, typically by being notified or interrupted, or until a certain amount of real time has elapsed.
`final void`	`wait(long timeoutMillis, int nanos)`	Causes the current thread to wait until it is awakened, typically by being notified or interrupted, or until a certain amount of real time has elapsed.

Field Details

isViewSizeSet

protected boolean isViewSizeSet

True when the viewport dimensions have been determined. The default is false.

lastPaintPosition

protected Point lastPaintPosition

The last viewPosition that we've painted, so we know how much of the backing store image is valid.

backingStore

@Deprecated protected boolean backingStore

Deprecated.

As of Java 2 platform v1.3

True when this viewport is maintaining an offscreen image of its contents, so that some scrolling can take place using fast "bit-blit" operations instead of by accessing the view object to construct the display. The default is false.

See Also:

backingStoreImage

protected transient Image backingStoreImage

The view image used for a backing store.

scrollUnderway

protected boolean scrollUnderway

The scrollUnderway flag is used for components like JList. When the downarrow key is pressed on a JList and the selected cell is the last in the list, the scrollpane autoscrolls. Here, the old selected cell needs repainting and so we need a flag to make the viewport do the optimized painting only when there is an explicit call to setViewPosition(Point). When setBounds is called through other routes, the flag is off and the view repaints normally. Another approach would be to remove this from the JViewport class and have the JList manage this case by using setBackingStoreEnabled. The default is false.

BLIT_SCROLL_MODE

public static final int BLIT_SCROLL_MODE

Use graphics.copyArea to implement scrolling. This is the fastest for most applications.

Since:

1.3

See Also:

BACKINGSTORE_SCROLL_MODE

public static final int BACKINGSTORE_SCROLL_MODE

Draws viewport contents into an offscreen image. This was previously the default mode for JTable. This mode may offer advantages over "blit mode" in some cases, but it requires a large chunk of extra RAM.

Since:

1.3

See Also:

SIMPLE_SCROLL_MODE

public static final int SIMPLE_SCROLL_MODE

This mode uses the very simple method of redrawing the entire contents of the scrollpane each time it is scrolled. This was the default behavior in Swing 1.0 and Swing 1.1. Either of the other two options will provide better performance in most cases.

Since:

1.3

See Also:

Constructor Details

JViewport

public JViewport()

Creates a JViewport.

Method Details

getUI

public ViewportUI getUI()

Returns the L&F object that renders this component.

Overrides:: getUI in class JComponent
Returns:: a ViewportUI object
Since:: 1.3

setUI

@BeanProperty(hidden=true, visualUpdate=true, description="The UI object that implements the Component's LookAndFeel.") public void setUI(ViewportUI ui)

Sets the L&F object that renders this component.

Parameters:

ui - the ViewportUI L&F object

Since:

1.3

See Also:

updateUI

public void updateUI()

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

Overrides:

updateUI in class JComponent

See Also:

getUIClassID

public String getUIClassID()

Returns a string that specifies the name of the L&F class that renders this component.

Overrides:

getUIClassID in class JComponent

Returns:

the string "ViewportUI"

See Also:

addImpl

protected void addImpl(Component child, Object constraints, int index)

Sets the JViewport's one lightweight child, which can be null. (Since there is only one child which occupies the entire viewport, the constraints and index arguments are ignored.)

Overrides:

addImpl in class Container

Parameters:

child - the lightweight child of the viewport

constraints - the constraints to be respected

index - the index

See Also:

remove

public void remove(Component child)

Removes the Viewports one lightweight child.

Overrides:

remove in class Container

Parameters:

child - the component to be removed

See Also:

scrollRectToVisible

public void scrollRectToVisible(Rectangle contentRect)

Scrolls the view so that Rectangle within the view becomes visible.

This attempts to validate the view before scrolling if the view is currently not valid - isValid returns false. To avoid excessive validation when the containment hierarchy is being created this will not validate if one of the ancestors does not have a peer, or there is no validate root ancestor, or one of the ancestors is not a Window.

Note that this method will not scroll outside of the valid viewport; for example, if contentRect is larger than the viewport, scrolling will be confined to the viewport's bounds.

Overrides:

scrollRectToVisible in class JComponent

Parameters:

contentRect - the Rectangle to display

See Also:

setBorder

public final void setBorder(Border border)

The viewport "scrolls" its child (called the "view") by the normal parent/child clipping (typically the view is moved in the opposite direction of the scroll). A non-null border, or non-zero insets, isn't supported, to prevent the geometry of this component from becoming complex enough to inhibit subclassing. To create a JViewport with a border, add it to a JPanel that has a border.

Note: If border is non-null, this method will throw an exception as borders are not supported on a JViewPort.

Overrides:

setBorder in class JComponent

Parameters:

border - the Border to set

Throws:

IllegalArgumentException - this method is not implemented

See Also:

getInsets

public final Insets getInsets()

Returns the insets (border) dimensions as (0,0,0,0), since borders are not supported on a JViewport.

Overrides:

getInsets in class JComponent

Returns:

a Rectangle of zero dimension and zero origin

See Also:

getInsets

@BeanProperty(expert=true) public final Insets getInsets(Insets insets)

Returns an Insets object containing this JViewports inset values. The passed-in Insets object will be reinitialized, and all existing values within this object are overwritten.

Overrides:

getInsets in class JComponent

Parameters:

insets - the Insets object which can be reused

Returns:

this viewports inset values

See Also:

isOptimizedDrawingEnabled

public boolean isOptimizedDrawingEnabled()

The JViewport overrides the default implementation of this method (in JComponent) to return false. This ensures that the drawing machinery will call the Viewport's paint implementation rather than messaging the JViewport's children directly.

Overrides:: isOptimizedDrawingEnabled in class JComponent
Returns:: false

isPaintingOrigin

protected boolean isPaintingOrigin()

Returns true if scroll mode is a BACKINGSTORE_SCROLL_MODE to cause painting to originate from JViewport, or one of its ancestors. Otherwise returns false.

Overrides:

isPaintingOrigin in class JComponent

Returns:

true if scroll mode is a BACKINGSTORE_SCROLL_MODE.

See Also:

paint

public void paint(Graphics g)

Depending on whether the backingStore is enabled, either paint the image through the backing store or paint just the recently exposed part, using the backing store to "blit" the remainder.

The term "blit" is the pronounced version of the PDP-10 BLT (BLock Transfer) instruction, which copied a block of bits. (In case you were curious.)

Overrides:

paint in class JComponent

Parameters:

g - the Graphics context within which to paint

See Also:

reshape

public void reshape(int x, int y, int w, int h)

Sets the bounds of this viewport. If the viewport's width or height has changed, fire a StateChanged event.

Overrides:

reshape in class JComponent

Parameters:

x - left edge of the origin

y - top edge of the origin

w - width in pixels

h - height in pixels

See Also:

setScrollMode

@BeanProperty(bound=false, enumerationValues={"JViewport.BLIT_SCROLL_MODE","JViewport.BACKINGSTORE_SCROLL_MODE","JViewport.SIMPLE_SCROLL_MODE"}, description="Method of moving contents for incremental scrolls.") public void setScrollMode(int mode)

Used to control the method of scrolling the viewport contents. You may want to change this mode to get maximum performance for your use case.

Parameters:

mode - one of the following values:

JViewport.BLIT_SCROLL_MODE
JViewport.BACKINGSTORE_SCROLL_MODE
JViewport.SIMPLE_SCROLL_MODE

Since:

1.3

See Also:

getScrollMode

public int getScrollMode()

Returns the current scrolling mode.

Returns:

the scrollMode property

Since:

1.3

See Also:

isBackingStoreEnabled

@Deprecated public boolean isBackingStoreEnabled()

Deprecated.

As of Java 2 platform v1.3, replaced by getScrollMode().

Returns true if this viewport is maintaining an offscreen image of its contents.

Returns:: true if scrollMode is BACKINGSTORE_SCROLL_MODE

setBackingStoreEnabled

@Deprecated public void setBackingStoreEnabled(boolean enabled)

Deprecated.

As of Java 2 platform v1.3, replaced by setScrollMode().

If true if this viewport will maintain an offscreen image of its contents. The image is used to reduce the cost of small one dimensional changes to the viewPosition. Rather than repainting the entire viewport we use Graphics.copyArea to effect some of the scroll.

Parameters:: enabled - if true, maintain an offscreen backing store

getView

public Component getView()

Returns the JViewport's one child or null.

Returns:

the viewports child, or null if none exists

See Also:

setView

public void setView(Component view)

Sets the JViewport's one lightweight child (view), which can be null.

Parameters:

view - the viewport's new lightweight child

See Also:

getViewSize

public Dimension getViewSize()

If the view's size hasn't been explicitly set, return the preferred size, otherwise return the view's current size. If there is no view, return 0,0.

Returns:: a Dimension object specifying the size of the view

setViewSize

public void setViewSize(Dimension newSize)

Sets the size of the view. A state changed event will be fired.

Parameters:: newSize - a Dimension object specifying the new size of the view

getViewPosition

public Point getViewPosition()

Returns the view coordinates that appear in the upper left hand corner of the viewport, or 0,0 if there's no view.

Returns:: a Point object giving the upper left coordinates

setViewPosition

public void setViewPosition(Point p)

Sets the view coordinates that appear in the upper left hand corner of the viewport, does nothing if there's no view.

Parameters:: p - a Point object giving the upper left coordinates

getViewRect

public Rectangle getViewRect()

Returns a rectangle whose origin is getViewPosition and size is getExtentSize. This is the visible part of the view, in view coordinates.

Returns:: a Rectangle giving the visible part of the view using view coordinates.

computeBlit

protected boolean computeBlit(int dx, int dy, Point blitFrom, Point blitTo, Dimension blitSize, Rectangle blitPaint)

Computes the parameters for a blit where the backing store image currently contains oldLoc in the upper left hand corner and we're scrolling to newLoc. The parameters are modified to return the values required for the blit.

Parameters:: dx - the horizontal delta; dy - the vertical delta; blitFrom - the Point we're blitting from; blitTo - the Point we're blitting to; blitSize - the Dimension of the area to blit; blitPaint - the area to blit
Returns:: true if the parameters are modified and we're ready to blit; false otherwise

getExtentSize

public Dimension getExtentSize()

Returns the size of the visible part of the view in view coordinates.

Returns:: a Dimension object giving the size of the view

toViewCoordinates

public Dimension toViewCoordinates(Dimension size)

Converts a size in pixel coordinates to view coordinates. Subclasses of viewport that support "logical coordinates" will override this method.

Parameters:: size - a Dimension object using pixel coordinates
Returns:: a Dimension object converted to view coordinates

toViewCoordinates

public Point toViewCoordinates(Point p)

Converts a point in pixel coordinates to view coordinates. Subclasses of viewport that support "logical coordinates" will override this method.

Parameters:: p - a Point object using pixel coordinates
Returns:: a Point object converted to view coordinates

setExtentSize

public void setExtentSize(Dimension newExtent)

Sets the size of the visible part of the view using view coordinates.

Parameters:: newExtent - a Dimension object specifying the size of the view

createViewListener

protected JViewport.ViewListener createViewListener()

Creates a listener for the view.

Returns:: a ViewListener

createLayoutManager

protected LayoutManager createLayoutManager()

Subclassers can override this to install a different layout manager (or null) in the constructor. Returns the LayoutManager to install on the JViewport.

Returns:: a LayoutManager

addChangeListener

public void addChangeListener(ChangeListener l)

Adds a ChangeListener to the list that is notified each time the view's size, position, or the viewport's extent size has changed.

Parameters:

l - the ChangeListener to add

See Also:

removeChangeListener

public void removeChangeListener(ChangeListener l)

Removes a ChangeListener from the list that's notified each time the views size, position, or the viewports extent size has changed.

Parameters:

l - the ChangeListener to remove

See Also:

getChangeListeners

public ChangeListener[] getChangeListeners()

Returns an array of all the ChangeListeners added to this JViewport 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 ChangeListeners when the views size, position, or the viewports extent size has changed.

See Also:

repaint

public void repaint(long tm, int x, int y, int w, int h)

Always repaint in the parents coordinate system to make sure only one paint is performed by the RepaintManager.

Overrides:

repaint in class JComponent

Parameters:

tm - maximum time in milliseconds before update

x - the x coordinate (pixels over from left)

y - the y coordinate (pixels down from top)

w - the width

h - the height

See Also:

paramString

protected String paramString()

Returns a string representation of this JViewport. This method is intended to be used only for debugging purposes, and 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 JViewport

firePropertyChange

protected void firePropertyChange(String propertyName, Object oldValue, Object newValue)

Notifies listeners of a property change. This is subclassed to update the windowBlit property. (The putClientProperty property is final).

Overrides:: firePropertyChange in class Component
Parameters:: propertyName - a string containing the property name; oldValue - the old value of the property; newValue - the new value of the property

getAccessibleContext

public AccessibleContext getAccessibleContext()

Gets the AccessibleContext associated with this JViewport. For viewports, the AccessibleContext takes the form of an AccessibleJViewport. A new AccessibleJViewport instance is created if necessary.

Specified by:: getAccessibleContext in interface Accessible
Overrides:: getAccessibleContext in class Component
Returns:: an AccessibleJViewport that serves as the AccessibleContext of this JViewport

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