Refer to AWT Threading Issues for details on AWT's threading model.
Parameters:
- l - the component listener
Since: JDK1.1
See Also: ComponentEvent, ComponentListener, Component.removeComponentListener(java.awt.event.ComponentListener), Component.getComponentListeners(),

Refer to AWT Threading Issues for details on AWT's threading model.
Parameters:
- l - the focus listener
Since: JDK1.1
See Also: FocusEvent, FocusListener, Component.removeFocusListener(java.awt.event.FocusListener), Component.getFocusListeners(),

Refer to AWT Threading Issues for details on AWT's threading model.
Parameters:
- l - the hierarchy bounds listener
Since: 1.3
See Also: HierarchyEvent, HierarchyBoundsListener, Component.removeHierarchyBoundsListener(java.awt.event.HierarchyBoundsListener), Component.getHierarchyBoundsListeners(),

Refer to AWT Threading Issues for details on AWT's threading model.
Parameters:
- l - the hierarchy listener
Since: 1.3
See Also: HierarchyEvent, HierarchyListener, Component.removeHierarchyListener(java.awt.event.HierarchyListener), Component.getHierarchyListeners(),

Refer to AWT Threading Issues for details on AWT's threading model.
Parameters:
- l - the input method listener
Since: 1.2
See Also: InputMethodEvent, InputMethodListener, Component.removeInputMethodListener(java.awt.event.InputMethodListener), Component.getInputMethodListeners(), Component.getInputMethodRequests(),

Refer to AWT Threading Issues for details on AWT's threading model.
Parameters:
- l - the key listener.
Since: JDK1.1
See Also: KeyEvent, KeyListener, Component.removeKeyListener(java.awt.event.KeyListener), Component.getKeyListeners(),

Refer to AWT Threading Issues for details on AWT's threading model.
Parameters:
- l - the mouse listener
Since: JDK1.1
See Also: MouseEvent, MouseListener, Component.removeMouseListener(java.awt.event.MouseListener), Component.getMouseListeners(),

Refer to AWT Threading Issues for details on AWT's threading model.
Parameters:
- l - the mouse motion listener
Since: JDK1.1
See Also: MouseEvent, MouseMotionListener, Component.removeMouseMotionListener(java.awt.event.MouseMotionListener), Component.getMouseMotionListeners(),

For information on how mouse wheel events are dispatched, see the class description for MouseWheelEvent.

If l is null, no exception is thrown and no action is performed.

Refer to AWT Threading Issues for details on AWT's threading model.
Parameters:
- l - the mouse wheel listener
Since: 1.4
See Also: MouseWheelEvent, MouseWheelListener, Component.removeMouseWheelListener(java.awt.event.MouseWheelListener), Component.getMouseWheelListeners(),

This method does not cause the image to begin loading. An application must use the prepareImage method to force the loading of an image.

Information on the flags returned by this method can be found with the discussion of the ImageObserver interface.
Returns: the bitwise inclusive OR of ImageObserver flags indicating what information about the image is currently available
Parameters:
- image - the Image object whose status is being checked
- observer - the ImageObserver object to be notified as the image is being prepared
Since: JDK1.0
See Also: Component.prepareImage(Image, int, int, java.awt.image.ImageObserver), Toolkit.checkImage(Image, int, int, java.awt.image.ImageObserver), ImageObserver,

This method does not cause the image to begin loading. An application must use the prepareImage method to force the loading of an image.

The checkImage method of Component calls its peer's checkImage method to calculate the flags. If this component does not yet have a peer, the component's toolkit's checkImage method is called instead.

Information on the flags returned by this method can be found with the discussion of the ImageObserver interface.
Returns: the bitwise inclusive OR of ImageObserver flags indicating what information about the image is currently available
Parameters:
- image - the Image object whose status is being checked
- width - the width of the scaled version whose status is to be checked
- height - the height of the scaled version whose status is to be checked
- observer - the ImageObserver object to be notified as the image is being prepared
Since: JDK1.0
See Also: Component.prepareImage(Image, int, int, java.awt.image.ImageObserver), Toolkit.checkImage(Image, int, int, java.awt.image.ImageObserver), ImageObserver,

This implementation of coalesceEvents coalesces two event types: mouse move (and drag) events, and paint (and update) events. For mouse move events the last event is always returned, causing intermediate moves to be discarded. For paint events, the new event is coalesced into a complex RepaintArea in the peer. The new AWTEvent is always returned.
Returns: a coalesced event, or null indicating that no coalescing was done
Parameters:
- existingEvent - the event already on the EventQueue
- newEvent - the event being posted to the EventQueue

Each time this method is called, the existing buffer strategy for this component is discarded.
Parameters:
- numBuffers - number of buffers to create, including the front buffer
Throws:
- IllegalArgumentException - if numBuffers is less than 1.
- IllegalStateException - if the component is not displayable
Since: 1.4
See Also: Component.isDisplayable(), Component.getBufferStrategy(),

Each time this method is called, dispose will be invoked on the existing BufferStrategy.
Parameters:
- numBuffers - number of buffers to create
- caps - the required capabilities for creating the buffer strategy; cannot be null
Throws:
- AWTException - if the capabilities supplied could not be supported or met; this may happen, for example, if there is not enough accelerated memory currently available, or if page flipping is specified but not possible.
- IllegalArgumentException - if numBuffers is less than 1, or if caps is null
Since: 1.4
See Also: Component.getBufferStrategy(),

Event types are automatically enabled when a listener for that event type is added to the component.

This method only needs to be invoked by subclasses of Component which desire to have the specified event types delivered to processEvent regardless of whether or not a listener is registered.
Parameters:
- eventsToEnable - the event mask defining the event types
Since: JDK1.1
See Also: Component.processEvent(java.awt.AWTEvent), Component.disableEvents(long), AWTEvent,

The default implementation returns -1. Subclasses that support baseline should override appropriately. If a value >= 0 is returned, then the component has a valid baseline for any size >= the minimum size and getBaselineResizeBehavior can be used to determine how the baseline changes with size.
Returns: the baseline or < 0 indicating there is no reasonable baseline
Parameters:
- width - the width to get the baseline for
- height - the height to get the baseline for
Throws:
- IllegalArgumentException - if width or height is < 0
Since: 1.6
See Also: Component.getBaselineResizeBehavior(), FontMetrics,

The default implementation returns BaselineResizeBehavior.OTHER. Subclasses that have a baseline should override appropriately. Subclasses should never return null; if the baseline can not be calculated return BaselineResizeBehavior.OTHER. Callers should first ask for the baseline using getBaseline and if a value >= 0 is returned use this method. It is acceptable for this method to return a value other than BaselineResizeBehavior.OTHER even if getBaseline returns a value less than 0.
Returns: an enum indicating how the baseline changes as the component size changes
Since: 1.6
See Also: Component.getBaseline(int, int),

Due to the asynchronous nature of native event handling, this method can return outdated values (for instance, after several calls of setLocation() in rapid succession). For this reason, the recommended method of obtaining a component's position is within java.awt.event.ComponentListener.componentMoved(), which is called after the operating system has finished moving the component.

For Containers it returns a non-null value if the mouse is above the Container itself or above any of its descendants. Use Container.getMousePosition(boolean) if you need to exclude children.

Sometimes the exact mouse coordinates are not important, and the only thing that matters is whether a specific Component is under the mouse pointer. If the return value of this method is null, mouse pointer is not directly above the Component.
Returns: mouse coordinates relative to this Component, or null
Throws:
- HeadlessException - if GraphicsEnvironment.isHeadless() returns true
Since: 1.5
See Also: Component.isShowing(), Container.getMousePosition(boolean),

The imageUpdate method of Component incrementally draws an image on the component as more of the bits of the image are available.

If the system property awt.image.incrementaldraw is missing or has the value true, the image is incrementally drawn. If the system property has any other value, then the image is not drawn until it has been completely loaded.

Also, if incremental drawing is in effect, the value of the system property awt.image.redrawrate is interpreted as an integer to give the maximum redraw rate, in milliseconds. If the system property is missing or cannot be interpreted as an integer, the redraw rate is once every 100ms.

The interpretation of the x, y, width, and height arguments depends on the value of the infoflags argument.
Returns: false if the infoflags indicate that the image is completely loaded; true otherwise.
Parameters:
- img - the image being observed
- infoflags - see imageUpdate for more information
- x - the x coordinate
- y - the y coordinate
- w - the width
- h - the height
Since: JDK1.0
See Also: ImageObserver, Graphics.drawImage(Image, int, int, Color, java.awt.image.ImageObserver), Graphics.drawImage(Image, int, int, java.awt.image.ImageObserver), Graphics.drawImage(Image, int, int, int, int, Color, java.awt.image.ImageObserver), Graphics.drawImage(Image, int, int, int, int, java.awt.image.ImageObserver), ImageObserver.imageUpdate(java.awt.Image, int, int, int, int, int),

A component is made displayable either when it is added to a displayable containment hierarchy or when its containment hierarchy is made displayable. A containment hierarchy is made displayable when its ancestor window is either packed or made visible.

A component is made undisplayable either when it is removed from a displayable containment hierarchy or when its containment hierarchy is made undisplayable. A containment hierarchy is made undisplayable when its ancestor window is disposed.
Returns: true if the component is displayable, false otherwise
Since: 1.2
See Also: Container.add(Component), Window.pack(), Window.show(), Container.remove(Component), Window.dispose(),

This method will always return false if this component is not displayable because it is impossible to determine the weight of an undisplayable component.
Returns: true if this component has a lightweight peer; false if it has a native peer or no peer
Since: 1.2
See Also: Component.isDisplayable(),

An opaque component paints every pixel within its rectangular region. A non-opaque component paints only some of its pixels, allowing the pixels underneath it to "show through". A component that does not fully paint its pixels therefore provides a degree of transparency. Only lightweight components can be transparent.

Subclasses that guarantee to always completely paint their contents should override this method and return true. All of the "heavyweight" AWT components are opaque.
Returns: true if this component is completely opaque
Since: 1.2
See Also: Component.isLightweight(),

Note: sometimes there is no way to detect whether the Component is actually visible to the user. This can happen when:

• the component has been added to a visible ScrollPane but the Component is not currently in the scroll pane's view port.
• the Component is obscured by another Component or Container.

The origin of the graphics context, its (0, 0) coordinate point, is the top-left corner of this component. The clipping region of the graphics context is the bounding rectangle of this component.
Parameters:
- g - the graphics context to use for painting
Since: JDK1.0
See Also: Component.paint(java.awt.Graphics),

The image data is downloaded asynchronously in another thread, and an appropriately scaled screen representation of the image is generated.
Returns: true if the image has already been fully prepared; false otherwise
Parameters:
- image - the instance of Image for which to prepare a screen representation
- width - the width of the desired screen representation
- height - the height of the desired screen representation
- observer - the ImageObserver object to be notified as the image is being prepared
Since: JDK1.0
See Also: ImageObserver,

The origin of the graphics context, its (0, 0) coordinate point, is the top-left corner of this component. The clipping region of the graphics context is the bounding rectangle of this component.
Parameters:
- g - the graphics context to use for printing
Since: JDK1.0
See Also: Component.print(Graphics),

This method is not called unless component events are enabled for this component. Component events are enabled when one of the following occurs:

• A ComponentListener object is registered via addComponentListener.
• Component events are enabled via enableEvents.

Note that if the event parameter is null the behavior is unspecified and may result in an exception.
Parameters:
- e - the component event
Since: JDK1.1
See Also: ComponentEvent, ComponentListener, Component.addComponentListener(java.awt.event.ComponentListener), Component.enableEvents(long),

This method is not called unless focus events are enabled for this component. Focus events are enabled when one of the following occurs:

• A FocusListener object is registered via addFocusListener.
• Focus events are enabled via enableEvents.

If focus events are enabled for a Component, the current KeyboardFocusManager determines whether or not a focus event should be dispatched to registered FocusListener objects. If the events are to be dispatched, the KeyboardFocusManager calls the Component's dispatchEvent method, which results in a call to the Component's processFocusEvent method.

If focus events are enabled for a Component, calling the Component's dispatchEvent method with a FocusEvent as the argument will result in a call to the Component's processFocusEvent method regardless of the current KeyboardFocusManager.

Note that if the event parameter is null the behavior is unspecified and may result in an exception.
Parameters:
- e - the focus event
Since: JDK1.1
See Also: FocusEvent, FocusListener, KeyboardFocusManager, Component.addFocusListener(java.awt.event.FocusListener), Component.enableEvents(long), Component.dispatchEvent(java.awt.AWTEvent),

This method is not called unless hierarchy bounds events are enabled for this component. Hierarchy bounds events are enabled when one of the following occurs:

• An HierarchyBoundsListener object is registered via addHierarchyBoundsListener.
• Hierarchy bounds events are enabled via enableEvents.

Note that if the event parameter is null the behavior is unspecified and may result in an exception.
Parameters:
- e - the hierarchy event
Since: 1.3
See Also: HierarchyEvent, HierarchyBoundsListener, Component.addHierarchyBoundsListener(java.awt.event.HierarchyBoundsListener), Component.enableEvents(long),

This method is not called unless hierarchy events are enabled for this component. Hierarchy events are enabled when one of the following occurs:

• An HierarchyListener object is registered via addHierarchyListener.
• Hierarchy events are enabled via enableEvents.

Note that if the event parameter is null the behavior is unspecified and may result in an exception.
Parameters:
- e - the hierarchy event
Since: 1.3
See Also: HierarchyEvent, HierarchyListener, Component.addHierarchyListener(java.awt.event.HierarchyListener), Component.enableEvents(long),

This method is not called unless input method events are enabled for this component. Input method events are enabled when one of the following occurs:

• An InputMethodListener object is registered via addInputMethodListener.
• Input method events are enabled via enableEvents.

Note that if the event parameter is null the behavior is unspecified and may result in an exception.
Parameters:
- e - the input method event
Since: 1.2
See Also: InputMethodEvent, InputMethodListener, Component.addInputMethodListener(java.awt.event.InputMethodListener), Component.enableEvents(long),

This method is not called unless key events are enabled for this component. Key events are enabled when one of the following occurs:

• A KeyListener object is registered via addKeyListener.
• Key events are enabled via enableEvents.

If key events are enabled for a Component, the current KeyboardFocusManager determines whether or not a key event should be dispatched to registered KeyListener objects. The DefaultKeyboardFocusManager will not dispatch key events to a Component that is not the focus owner or is not showing.

As of J2SE 1.4, KeyEvents are redirected to the focus owner. Please see the Focus Specification for further information.

Calling a Component's dispatchEvent method with a KeyEvent as the argument will result in a call to the Component's processKeyEvent method regardless of the current KeyboardFocusManager as long as the component is showing, focused, and enabled, and key events are enabled on it.

If the event parameter is null the behavior is unspecified and may result in an exception.
Parameters:
- e - the key event
Since: JDK1.1
See Also: KeyEvent, KeyListener, KeyboardFocusManager, DefaultKeyboardFocusManager, Component.processEvent(java.awt.AWTEvent), Component.dispatchEvent(java.awt.AWTEvent), Component.addKeyListener(java.awt.event.KeyListener), Component.enableEvents(long), Component.isShowing(),

This method is not called unless mouse events are enabled for this component. Mouse events are enabled when one of the following occurs:

• A MouseListener object is registered via addMouseListener.
• Mouse events are enabled via enableEvents.

Note that if the event parameter is null the behavior is unspecified and may result in an exception.
Parameters:
- e - the mouse event
Since: JDK1.1
See Also: MouseEvent, MouseListener, Component.addMouseListener(java.awt.event.MouseListener), Component.enableEvents(long),

This method is not called unless mouse motion events are enabled for this component. Mouse motion events are enabled when one of the following occurs:

• A MouseMotionListener object is registered via addMouseMotionListener.
• Mouse motion events are enabled via enableEvents.

Note that if the event parameter is null the behavior is unspecified and may result in an exception.
Parameters:
- e - the mouse motion event
Since: JDK1.1
See Also: MouseEvent, MouseMotionListener, Component.addMouseMotionListener(java.awt.event.MouseMotionListener), Component.enableEvents(long),

This method is not called unless mouse wheel events are enabled for this component. Mouse wheel events are enabled when one of the following occurs:

• A MouseWheelListener object is registered via addMouseWheelListener.
• Mouse wheel events are enabled via enableEvents.

For information on how mouse wheel events are dispatched, see the class description for MouseWheelEvent.

Note that if the event parameter is null the behavior is unspecified and may result in an exception.
Parameters:
- e - the mouse wheel event
Since: 1.4
See Also: MouseWheelEvent, MouseWheelListener, Component.addMouseWheelListener(java.awt.event.MouseWheelListener), Component.enableEvents(long),