Class java.awt.Component

public Dimension getPreferredSize()

Gets the preferred size of this component.

Returns:

A dimension object indicating this component's preferred size.

See Also:

getMinimumSize, LayoutManager

public Dimension preferredSize()

Note: preferredSize() is deprecated. As of JDK version 1.1, replaced by getPreferredSize().

public Dimension getMinimumSize()

Gets the mininimum size of this component.

Returns:

A dimension object indicating this component's minimum size.

See Also:

getPreferredSize, awtLayoutManager

public Dimension minimumSize()

Note: minimumSize() is deprecated. As of JDK version 1.1, replaced by getMinimumSize().

public Dimension getMaximumSize()

Gets the maximum size of this component.

Returns:

A dimension object indicating this component's maximum size.

See Also:

getMinimumSize, getPreferredSize, LayoutManager

public float getAlignmentX()

Returns the alignment along the x axis. This specifies how the component would like to be aligned relative to other components. The value should be a number between 0 and 1 where 0 represents alignment along the origin, 1 is aligned the furthest away from the origin, 0.5 is centered, etc.

public float getAlignmentY()

Returns the alignment along the y axis. This specifies how the component would like to be aligned relative to other components. The value should be a number between 0 and 1 where 0 represents alignment along the origin, 1 is aligned the furthest away from the origin, 0.5 is centered, etc.

public void doLayout()

Prompts the layout manager to lay out this component. This is usually called when the component (more specifically, container) is validated.

See Also:

validate, LayoutManager

public void layout()

Note: layout() is deprecated. As of JDK version 1.1, replaced by doLayout().

public void validate()

Ensures that this component has a valid layout. This method is primarily intended to operate on instances of Container.

See Also:

invalidate, doLayout, LayoutManager, validate

public void invalidate()

Invalidates this component. This component and all parents above it are marked as needing to be laid out. This method can be called often, so it needs to execute quickly.

See Also:

validate, doLayout, LayoutManager

public Graphics getGraphics()

Creates a graphics context for this component. This method will return null if this component is currently not on the screen.

Returns:

A graphics context for this component, or null if it has none.

See Also:

paint

public FontMetrics getFontMetrics(Font font)

Gets the font metrics for the specified font.

Parameters:

font - The font for which font metrics is to be obtained.

font - the font.

Returns:

The font metrics for font.

See Also:

getFont, getPeer, getFontMetrics, getFontMetrics

public synchronized void setCursor(Cursor cursor)

Set the cursor image to a predefined cursor.

Parameters:

cursor - One of the constants defined by the Cursor class. If this parameter is null then this component will inherit the cursor of its parent.

See Also:

getCursor, Cursor

public Cursor getCursor()

Gets the cursor set on this component.

Returns:

The cursor for this component.

See Also:

setCursor, Cursor

public void paint(Graphics g)

Paints this component. This method is called when the contents of the component should be painted in response to the component first being shown or damage needing repair. The clip rectangle in the Graphics parameter will be set to the area which needs to be painted.

Parameters:

g - The graphics context to use for painting.

See Also:

update

public void update(Graphics g)

Updates this component.

The AWT calls the update method in response to a call to repaintupdate or paint. You can assume that the background is not cleared.

The updatemethod of Component does the following:

• Clears this component by filling it with the background color.
• Sets the color of the graphics context to be the foreground color of this component.
• Calls this component's paint method to completely redraw this component.

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 specified context to use for updating.

See Also:

paint, repaint

public void paintAll(Graphics g)

Paints this component and all of its subcomponents.

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.

See Also:

paint

public void repaint()

Repaints this component.

This method causes a call to this component's update method as soon as possible.

See Also:

update

public void repaint(long tm)

Repaints the component. This will result in a call to update within tm milliseconds.

Parameters:

tm - maximum time in milliseconds before update

See Also:

paint, update

public void repaint(int x,
                     int y,
                     int width,
                     int height)

Repaints the specified rectangle of this component.

This method causes a call to this component's update method as soon as possible.

Parameters:

x - the x coordinate.

y - the y coordinate.

width - the width.

height - the height.

See Also:

update

public void repaint(long tm,
                     int x,
                     int y,
                     int width,
                     int height)

Repaints the specified rectangle of this component within tm milliseconds.

This method causes a call to this component's update method.

Parameters:

tm - maximum time in milliseconds before update.

x - the x coordinate.

y - the y coordinate.

width - the width.

height - the height.

See Also:

update

public void print(Graphics g)

Prints this component. Applications should override this method for components that must do special processing before being printed or should be printed differently than they are painted.

The default implementation of this method calls the paint method.

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.

See Also:

paint

public void printAll(Graphics g)

Prints this component and all of its subcomponents.

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.

See Also:

print

public boolean imageUpdate(Image img,
                            int flags,
                            int x,
                            int y,
                            int w,
                            int h)

Repaints the component when the image has changed. This imageUpdate method of an ImageObserver is called when more information about an image which had been previously requested using an asynchronous routine such as the drawImage method of Graphics becomes available. See the definition of imageUpdate for more information on this method and its arguments.

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.

Parameters:

img - the image being observed.

infoflags - see imageUpdate for more information.

x - the x coordinate.

y - the y coordinate.

width - the width.

height - the height.

Returns:

true if the flags indicate that the image is completely loaded; false otherwise.

See Also:

ImageObserver, drawImage, drawImage, drawImage, drawImage, imageUpdate

public Image createImage(ImageProducer producer)

Creates an image from the specified image producer.

Parameters:

producer - the image producer

Returns:

the image produced.

public Image createImage(int width,
                          int height)

Creates an off-screen drawable image to be used for double buffering.

Parameters:

width - the specified width.

height - the specified height.

Returns:

an off-screen drawable image, which can be used for double buffering.

public boolean prepareImage(Image image,
ImageObserver observer)

Prepares an image for rendering on this component. The image data is downloaded asynchronously in another thread and the appropriate screen representation of the image is generated.

Parameters:

image - the Image for which to prepare a screen representation.

observer - the ImageObserver object to be notified as the image is being prepared.

Returns:

true if the image has already been fully prepared; false otherwise.

public boolean prepareImage(Image image,
                             int width,
                             int height,
ImageObserver observer)

Prepares an image for rendering on this component at the specified width and height.

The image data is downloaded asynchronously in another thread, and an appropriately scaled screen representation of the image is generated.

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.

Returns:

true if the image has already been fully prepared; false otherwise.

See Also:

ImageObserver

public int checkImage(Image image,
ImageObserver observer)

Returns the status of the construction of a screen representation of the specified image.

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.

Parameters:

image - the Image object whose status is being checked.

observer - the ImageObserver object to be notified as the image is being prepared.

Returns:

the bitwise inclusive OR of ImageObserver flags indicating what information about the image is currently available.

See Also:

prepareImage, checkImage, ImageObserver

public int checkImage(Image image,
                       int width,
                       int height,
ImageObserver observer)

Returns the status of the construction of a screen representation of the specified image.

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.

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.

Returns:

the bitwise inclusive OR of ImageObserver flags indicating what information about the image is currently available.

See Also:

prepareImage, checkImage, _top_

public boolean contains(int x,
                         int y)

Checks whether this component "contains" the specified point, where x and y are defined to be relative to the coordinate system of this component.

Parameters:

x - the x coordinate of the point.

y - the y coordinate of the point.

See Also:

getComponentAt

public boolean inside(int x,
                       int y)

Note: inside() is deprecated. As of JDK version 1.1, replaced by contains(int, int).

public 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.

Parameters:

p - the point.

See Also:

getComponentAt

public Component getComponentAt(int x,
                                 int y)

Determines if this component or one of its immediate subcomponents contains the (x, y) location, and if so, returns the containing component. This method only looks one level deep. If the point (x, y) is inside a subcomponent that itself has subcomponents, it does not go looking down the subcomponent tree.

The locate method of Component simply returns the component itself if the (x, y) coordinate location is inside its bounding box, and null otherwise.

Parameters:

x - the x coordinate.

y - the y coordinate.

Returns:

the component or subcomponent that contains the (x, y) location; null if the location is outside this component.

See Also:

contains

public Component locate(int x,
                         int y)

Note: locate() is deprecated. As of JDK version 1.1, replaced by getComponentAt(int, int).

public Component getComponentAt(Point p)

Returns the component or subcomponent that contains the specified point.

Parameters:

p - the point.

See Also:

contains

public void deliverEvent(Event e)

Note: deliverEvent() is deprecated. As of JDK version 1.1, replaced by dispatchEvent(AWTEvent e).

public final void dispatchEvent(AWTEvent e)

Dispatches an event to this component or one of its sub components.

Parameters:

e - the event

public boolean postEvent(Event e)

Note: postEvent() is deprecated. As of JDK version 1.1, replaced by dispatchEvent(AWTEvent).

public synchronized void addComponentListener(ComponentListener l)

Adds the specified component listener to receive component events from this component.

Parameters:

l - the component listener.

See Also:

ComponentEvent, ComponentListener, removeComponentListener

public synchronized void removeComponentListener(ComponentListener l)

Removes the specified component listener so that it no longer receives component events from this component.

Parameters:

l - the component listener.

See Also:

ComponentEvent, ComponentListener, addComponentListener

public synchronized void addFocusListener(FocusListener l)

Adds the specified focus listener to receive focus events from this component.

Parameters:

l - the focus listener.

See Also:

FocusEvent, FocusListener, removeFocusListener

public synchronized void removeFocusListener(FocusListener l)

Removes the specified focus listener so that it no longer receives focus events from this component.

Parameters:

l - the focus listener.

See Also:

FocusEvent, FocusListener, addFocusListener

public synchronized void addKeyListener(KeyListener l)

Adds the specified key listener to receive key events from this component.

Parameters:

l - the key listener.

See Also:

KeyEvent, KeyListener, removeKeyListener

public synchronized void removeKeyListener(KeyListener l)

Removes the specified key listener so that it no longer receives key events from this component.

Parameters:

l - the key listener.

See Also:

KeyEvent, KeyListener, addKeyListener

public synchronized void addMouseListener(MouseListener l)

Adds the specified mouse listener to receive mouse events from this component.

Parameters:

l - the mouse listener.

See Also:

MouseEvent, MouseListener, removeMouseListener

public synchronized void removeMouseListener(MouseListener l)

Removes the specified mouse listener so that it no longer receives mouse events from this component.

Parameters:

l - the mouse listener.

See Also:

MouseEvent, MouseListener, addMouseListener

public synchronized void addMouseMotionListener(MouseMotionListener l)

Adds the specified mouse motion listener to receive mouse motion events from this component.

Parameters:

l - the mouse motion listener.

See Also:

MouseMotionEvent, MouseMotionListener, removeMouseMotionListener

public synchronized void removeMouseMotionListener(MouseMotionListener l)

Removes the specified mouse motion listener so that it no longer receives mouse motion events from this component.

Parameters:

l - the mouse motion listener.

See Also:

MouseMotionEvent, MouseMotionListener, addMouseMotionListener

protected final void enableEvents(long eventsToEnable)

Enables the events defined by the specified event mask parameter to be delivered to this component.

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.

See Also:

processEvent, disableEvents

protected final void disableEvents(long eventsToDisable)

Disables the events defined by the specified event mask parameter from being delivered to this component.

Parameters:

eventsToDisable - the event mask defining the event types

See Also:

enableEvents

protected void processEvent(AWTEvent e)

Processes events occurring on this component. By default this method calls the appropriate process<event type>Event method for the given class of event.

Parameters:

e - the event.

See Also:

processComponentEvent, processFocusEvent, processKeyEvent, processMouseEvent, processMouseMotionEvent

protected void processComponentEvent(ComponentEvent e)

Processes component events occurring on this component by dispatching them to any registered ComponentListener objects.

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.

Parameters:

e - the component event.

See Also:

ComponentEvent, ComponentListener, addComponentListener, enableEvents

protected void processFocusEvent(FocusEvent e)

Processes focus events occurring on this component by dispatching them to any registered FocusListener objects.

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.

Parameters:

e - the focus event.

See Also:

FocusEvent, FocusListener, addFocusListener, enableEvents

protected void processKeyEvent(KeyEvent e)

Processes key events occurring on this component by dispatching them to any registered objects.

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.

Parameters:

e - the key event.

See Also:

KeyEvent, KeyListener, addKeyListener, enableEvents

protected void processMouseEvent(MouseEvent e)

Processes mouse events occurring on this component by dispatching them to any registered MouseListener objects.

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.

Parameters:

e - the mouse event.

See Also:

MouseEvent, MouseListener, addMouseListener, enableEvents

protected void processMouseMotionEvent(MouseEvent e)

Processes mouse motion events occurring on this component by dispatching them to any registered MouseMotionListener objects.

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.

Parameters:

e - the mouse motion event.

See Also:

MouseMotionEvent, MouseMotionListener, addMouseMotionListener, enableEvents

public boolean handleEvent(Event evt)

Note: handleEvent() is deprecated. As of JDK version 1.1 replaced by processEvent(AWTEvent).

public boolean mouseDown(Event evt,
                          int x,
                          int y)

Note: mouseDown() is deprecated. As of JDK version 1.1, replaced by processMouseEvent(MouseEvent).

public boolean mouseDrag(Event evt,
                          int x,
                          int y)

Note: mouseDrag() is deprecated. As of JDK version 1.1, replaced by processMouseMotionEvent(MouseEvent).

public boolean mouseUp(Event evt,
                        int x,
                        int y)

Note: mouseUp() is deprecated. As of JDK version 1.1, replaced by processMouseEvent(MouseEvent).

public boolean mouseMove(Event evt,
                          int x,
                          int y)

Note: mouseMove() is deprecated. As of JDK version 1.1, replaced by processMouseMotionEvent(MouseEvent).

public boolean mouseEnter(Event evt,
                           int x,
                           int y)

Note: mouseEnter() is deprecated. As of JDK version 1.1, replaced by processMouseEvent(MouseEvent).

public boolean mouseExit(Event evt,
                          int x,
                          int y)

Note: mouseExit() is deprecated. As of JDK version 1.1, replaced by processMouseEvent(MouseEvent).

public boolean keyDown(Event evt,
                        int key)

Note: keyDown() is deprecated. As of JDK version 1.1, replaced by processKeyEvent(KeyEvent).

public boolean keyUp(Event evt,
                      int key)

Note: keyUp() is deprecated. As of JDK version 1.1, replaced by processKeyEvent(KeyEvent).

public boolean action(Event evt,
Object what)

Note: action() is deprecated. As of JDK version 1.1, should register this component as ActionListener on component which fires action events.

public void addNotify()

Notifies this component that it has been added to a container and if a peer is required, it should be created. This method should be called by Container.add, and not by user code directly.

See Also:

removeNotify

public void removeNotify()

Notifies this component that it has been removed from its container and if a peers exists, it destroys it. This method should be called by Container.remove, and not by user code directly.

See Also:

addNotify

public boolean gotFocus(Event evt,
Object what)

Note: gotFocus() is deprecated. As of JDK version 1.1, replaced by processFocusEvent(FocusEvent).

public boolean lostFocus(Event evt,
Object what)

Note: lostFocus() is deprecated. As of JDK version 1.1, replaced by processFocusEvent(FocusEvent).

public boolean isFocusTraversable()

Returns the value of a flag that indicates whether this component can be traversed using Tab or Shift-Tab keyboard focus traversal. If this method returns "false", this component may still request the keyboard focus using requestFocus(), but it will not automatically be assigned focus during tab traversal.

Returns:

true if this component is focus-traverable; false otherwise.

public void requestFocus()

Requests that this component get the input focus.

This component's gotFocus method is called when this method is successful. The component must be visible on the screen for this request to be granted

See Also:

FocusEvent, addFocusListener, processFocusEvent, isFocusTraversable

public void transferFocus()

Transfers the focus to the next component.

See Also:

requestFocus, gotFocus

public void nextFocus()

Note: nextFocus() is deprecated. As of JDK version 1.1, replaced by transferFocus().

public synchronized void add(PopupMenu popup)

Adds the specified popup menu to the component.

Parameters:

popup - the popup menu to be added to the component.

See Also:

remove

public synchronized void remove(MenuComponent popup)

Removes the specified popup menu from the component.

Parameters:

popup - the popup menu to be removed.

See Also:

add

protected String paramString()

Returns the parameter string representing the state of this component. This string is useful for debugging.

Returns:

the parameter string of this component.

public String toString()

Returns a string representation of this component and its values.

Returns:

a string representation of this component.

Overrides:

toString in class Object

public void list()

Prints a listing of this component to the standard system output stream System.out.

See Also:

out

public void list(PrintStream out)

Prints a listing of this component to the specified output stream.

Parameters:

out - a print stream.

public void list(PrintStream out,
                  int indent)

Prints out a list, starting at the specified indention, to the specified print stream.

Parameters:

out - a print stream.

indent - number of spaces to indent.

See Also:

println

public void list(PrintWriter out)

Prints a listing to the specified print writer.

Parameters:

out - The print writer to print to.

public void list(PrintWriter out,
                  int indent)

Prints out a list, starting at the specified indention, to the specified print writer.

Parameters:

out - The print writer to print to.

indent - The number of spaces to indent.

See Also:

println

All Packages  Class Hierarchy  This Package  Previous  Next  Index