java.awt
Class Component
- public abstract class Component
- implements ImageObserver, MenuContainer, Serializable
- A component is an object having a graphical representation that can be displayed on the screen and that can interact with the user. Examples of components are the buttons, checkboxes, and scrollbars of a typical graphical user interface.
The Component
class is the abstract superclass of the nonmenu-related Abstract Window Toolkit components. Class Component
can also be extended directly to create a lightweight component. A lightweight component is a component that is not associated with a native opaque window.
- Version:
- 1.265, 02/28/00
- Author:
- Arthur van Hoff
- Sami Shaio
peer
transient ComponentPeer peer
- The peer of the component. The peer implements the component's behaviour. The peer is set when the Component is added to a container that also is a peer.
- See Also:
- #addNotify
- #removeNotify
parent
transient Container parent
- The parent of the object. It may be null for top-level components.
- See Also:
- #getParent
appContext
transient AppContext appContext
- The AppContext of the component. This is set in the constructor and never changes.
x
int x
- The x position of the component in the parent's coordinate system.
- See Also:
- #getLocation
y
int y
- The y position of the component in the parent's coordinate system.
- See Also:
- #getLocation
width
int width
- The width of the component.
- See Also:
- #getSize
height
int height
- The height of the component.
- See Also:
- #getSize
foreground
Color foreground
- The foreground color for this component. foreground color can be null.
- See Also:
- #getForeground
- #setForeground
background
Color background
- The background color for this component. background can be null.
- See Also:
- #getBackground
- #setBackground
font
Font font
- The font used by this component. The font can be null.
- See Also:
- #getFont
- #setFont
peerFont
Font peerFont
- The font which the peer is currently using. (null if no peer exists.)
cursor
Cursor cursor
- The cursor displayed when pointer is over this component. This value can be null.
- See Also:
- #getCursor
- #setCursor
locale
Locale locale
- The locale for the component.
- See Also:
- #getLocale
- #setLocale
graphicsConfig
transient GraphicsConfiguration graphicsConfig
- A reference to a GraphicsConfiguration object used to describe the characteristics of a graphics destination. This value can be null.
- Since:
- 1.3
- See Also:
- java.awt.GraphicsConfiguration
- #getGraphicsConfiguration
visible
boolean visible
- True when the object is visible. An object that is not visible is not drawn on the screen.
- See Also:
- #isVisible
- #setVisible
enabled
boolean enabled
- True when the object is enabled. An object that is not enabled does not interact with the user.
- See Also:
- #isEnabled
- #setEnabled
valid
boolean valid
- True when the object is valid. An invalid object needs to be layed out. This flag is set to false when the object size is changed.
- See Also:
- #isValid
- #validate
- #invalidate
dropTarget
DropTarget dropTarget
- The DropTarget associated with this Component.
- Since:
- 1.2
- See Also:
- #setDropTarget
- #getDropTarget
hasFocus
boolean hasFocus
- True if this component has enabled focus events and currently has the focus.
- See Also:
- #hasFocus
- #processFocusEvent
popups
Vector popups
- See Also:
- add()
name
private String name
- A components name. This field can be null.
- See Also:
- getName()
- setName(String)
nameExplicitlySet
private boolean nameExplicitlySet
- A bool to determine whether the name has been set explicitly. nameExplicitlySet will be false if the name has not been set and true if it has.
- See Also:
- getName()
- setName(String)
LOCK
static final Object LOCK
- The locking object for AWT component-tree and layout operations.
- See Also:
- #getTreeLock
minSize
Dimension minSize
- Internal, cached size information. (This field perhaps should have been transient).
prefSize
Dimension prefSize
- Internal, cached size information (This field perhaps should have been transient).
componentOrientation
transient ComponentOrientation componentOrientation
- The orientation for this component.
- See Also:
- #getComponentOrientation
- #setComponentOrientation
newEventsOnly
boolean newEventsOnly
- newEventsOnly will be true if the event is one of the event types enabled for the component. It will then allow for normal processing to continue. If it is false the event is passed to the components parent and up the ancestor tree until the event has been consumed.
- See Also:
- dispatchEvent()
actionListenerK
static final String actionListenerK
- Internal, constants for serialization
eventMask
long eventMask
- The eventMask is ONLY set by subclasses via enableEvents. The mask should NOT be set when listeners are registered so that we can distinguish the difference between when listeners request events and subclasses request them. One bit is used to indicate whether input methods are enabled; this bit is set by enableInputMethods and is on by default.
- See Also:
- enableInputMethods()
isInc
static boolean isInc
- Static properties for incremental drawing.
- See Also:
- #imageUpdate
TOP_ALIGNMENT
public static final float TOP_ALIGNMENT
- Ease-of-use constant for
getAlignmentY()
. Specifies an alignment to the top of the component.
- See Also:
- #getAlignmentY
CENTER_ALIGNMENT
public static final float CENTER_ALIGNMENT
- Ease-of-use constant for
getAlignmentY
and getAlignmentX
. Specifies an alignment to the center of the component
- See Also:
- #getAlignmentX
- #getAlignmentY
BOTTOM_ALIGNMENT
public static final float BOTTOM_ALIGNMENT
- Ease-of-use constant for
getAlignmentY
. Specifies an alignment to the bottom of the component.
- See Also:
- #getAlignmentY
LEFT_ALIGNMENT
public static final float LEFT_ALIGNMENT
- Ease-of-use constant for
getAlignmentX
. Specifies an alignment to the left side of the component.
- See Also:
- #getAlignmentX
RIGHT_ALIGNMENT
public static final float RIGHT_ALIGNMENT
- Ease-of-use constant for
getAlignmentX
. Specifies an alignment to the right side of the component.
- See Also:
- #getAlignmentX
changeSupport
private PropertyChangeSupport changeSupport
- If any PropertyChangeListeners have been registered, the changeSupport field describes them.
- Since:
- 1.2
- See Also:
- addPropertyChangeListener
- removePropertyChangeListener
- firePropertyChange
privateKey
private transient Object privateKey
- This object is used as a key for internal hashtables.
metrics
static Hashtable metrics
- saves an internal cache of FontMetrics for better performance *
componentSerializedDataVersion
private int componentSerializedDataVersion
- Component Serialized Data Version.
Component
protected Component()
- Constructs a new component. Class
Component
can be extended directly to create a lightweight component that does not utilize an opaque native window. A lightweight component must be hosted by a native container somewhere higher up in the component tree (for example, by a Frame
object).
constructComponentName
String constructComponentName()
- Construct a name for this component. Called by getName() when the name is null.
getName
public String getName()
- Gets the name of the component.
- Returns:
- This component's name.
- Since:
- JDK1.1
- See Also:
- #setName
setName
public void setName(String name)
- Sets the name of the component to the specified string.
- Parameters:
name
- The string that is to be this component's name.
- Since:
- JDK1.1
- See Also:
- #getName
getParent
public Container getParent()
- Gets the parent of this component.
- Returns:
- The parent container of this component.
- Since:
- JDK1.0
getPeer
public ComponentPeer getPeer()
- Deprecated. As of JDK version 1.1, programs should not directly manipulate peers. replaced by
boolean isDisplayable()
.
setDropTarget
public synchronized void setDropTarget(DropTarget dt)
- Associate a DropTarget with this Component. The Component will receive drops only if it is enabled.
- Parameters:
dt
- The DropTarget
- See Also:
- #isEnabled
getDropTarget
public synchronized DropTarget getDropTarget()
- Get the DropTarget associated with this Component
getGraphicsConfiguration
public GraphicsConfiguration getGraphicsConfiguration()
- Get the
GraphicsConfiguration
associated with this Component
. If the Component
has not been assigned a specific GraphicsConfiguration
, the GraphicsConfiguration
of the Component
object's top-level container is returned. If the Component
has been created, but not yet added to a Container
, this method returns null
.
- Returns:
- the
GraphicsConfiguration
used by this Component
or null
- Since:
- 1.3
resetGC
void resetGC()
- Reset this Componenet's GraphicsConfiguration back to a default value. For most Componenets, this is null. Called from the Toolkit thread, so NO CLIENT CODE.
checkGD
void checkGD(String stringID)
- Checks that this Component's GraphicsDevice idString matches the String argument
getTreeLock
public final Object getTreeLock()
- Gets the locking object for AWT component-tree and layout Gets this component's locking object (the object that owns the thread sychronization monitor) for AWT component-tree and layout operations.
- Returns:
- This component's locking object.
getToolkit
public Toolkit getToolkit()
- Gets the toolkit of this component. Note that the frame that contains a component controls which toolkit is used by that component. Therefore if the component is moved from one frame to another, the toolkit it uses may change.
- Returns:
- The toolkit of this component.
- Since:
- JDK1.0
isValid
public boolean isValid()
- Determines whether this component is valid. A component is valid when it is correctly sized and positioned within its parent container and all its children are also valid. Components are invalidated when they are first shown on the screen.
- Returns:
true
if the component is valid; false
otherwise.
- Since:
- JDK1.0
- See Also:
- #validate
- #invalidate
isDisplayable
public boolean isDisplayable()
- Determines whether this component is displayable. A component is displayable when it is connected to a native screen resource.
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:
- java.awt.Container#add(java.awt.Component)
- java.awt.Window#pack
- java.awt.Window#show
- java.awt.Container#remove(java.awt.Component)
- java.awt.Window#dispose
isVisible
public boolean isVisible()
- Determines whether this component should be visible when its parent is visible. Components are initially visible, with the exception of top level components such as
Frame
objects.
- Returns:
true
if the component is visible; false
otherwise.
- Since:
- JDK1.0
- See Also:
- #setVisible
isRecursivelyVisible
boolean isRecursivelyVisible()
- Determines whether this component will be displayed on the screen if it's displayable.
- Returns:
true
if the component and all of its ancestors are visible; false
otherwise.
isShowing
public boolean isShowing()
- Determines whether this component is showing on screen. This means that the component must be visible, and it must be in a container that is visible and showing.
- Returns:
true
if the component is showing; false
otherwise.
- Since:
- JDK1.0
- See Also:
- #setVisible
isEnabled
public boolean isEnabled()
- Determines whether this component is enabled. An enabled component can respond to user input and generate events. Components are enabled initially by default. A component may be enabled or disabled by calling its
setEnabled
method.
- Returns:
true
if the component is enabled; false
otherwise.
- Since:
- JDK1.0
- See Also:
- #setEnabled
setEnabled
public void setEnabled(boolean b)
- Enables or disables this component, depending on the value of the parameter
b
. An enabled component can respond to user input and generate events. Components are enabled initially by default.
- Parameters:
b
- If true
, this component is enabled; otherwise this component is disabled.
- Since:
- JDK1.1
- See Also:
- #isEnabled
enable
public void enable()
- Deprecated. As of JDK version 1.1, replaced by
setEnabled(boolean)
.
enable
public void enable(boolean b)
- Deprecated. As of JDK version 1.1, replaced by
setEnabled(boolean)
.
disable
public void disable()
- Deprecated. As of JDK version 1.1, replaced by
setEnabled(boolean)
.
isDoubleBuffered
public boolean isDoubleBuffered()
- Returns true if this component is painted to an offscreen image ("buffer") that's copied to the screen later. Component subclasses that support double buffering should override this method to return true if double buffering is enabled.
- Returns:
- false by default
enableInputMethods
public void enableInputMethods(boolean enable)
- Enables or disables input method support for this component. If input method support is enabled and the component also processes key events, incoming events are offered to the current input method and will only be processed by the component or dispatched to its listeners if the input method does not consume them. By default, input method support is enabled.
- Parameters:
enable
- true to enable, false to disable.
- Since:
- 1.2
- See Also:
- java.awt.Component#processKeyEvent
setVisible
public void setVisible(boolean b)
- Shows or hides this component depending on the value of parameter
b
.
- Parameters:
b
- If true
, shows this component; otherwise, hides this component.
- Since:
- JDK1.1
- See Also:
- #isVisible
show
public void show()
- Deprecated. As of JDK version 1.1, replaced by
setVisible(boolean)
.
show
public void show(boolean b)
- Deprecated. As of JDK version 1.1, replaced by
setVisible(boolean)
.
hide
public void hide()
- Deprecated. As of JDK version 1.1, replaced by
setVisible(boolean)
.
getForeground
public Color getForeground()
- Gets the foreground color of this component.
- Returns:
- This component's foreground color. If this component does not have a foreground color, the foreground color of its parent is returned.
- Since:
- JDK1.0
- See Also:
- #setForeground
setForeground
public void setForeground(Color c)
- Sets the foreground color of this component.
- Parameters:
c
- The color to become this component's foreground color. If this parameter is null then this component will inherit the foreground color of its parent.
- Since:
- JDK1.0
- See Also:
- #getForeground
getBackground
public Color getBackground()
- Gets the background color of this component.
- Returns:
- This component's background color. If this component does not have a background color, the background color of its parent is returned.
- Since:
- JDK1.0
- See Also:
- java.awt.Component#setBackground(java.awt.Color)
setBackground
public void setBackground(Color c)
- Sets the background color of this component.
- Parameters:
c
- The color to become this component's color. If this parameter is null then this component will inherit the background color of its parent. background color.
- Since:
- JDK1.0
- See Also:
- #getBackground
getFont
public Font getFont()
- Gets the font of this component.
- Returns:
- This component's font. If a font has not been set for this component, the font of its parent is returned.
- Since:
- JDK1.0
- See Also:
- #setFont
setFont
public void setFont(Font f)
- Sets the font of this component.
- Parameters:
f
- The font to become this component's font. If this parameter is null then this component will inherit the font of its parent.
- Since:
- JDK1.0
- See Also:
- #getFont
getLocale
public Locale getLocale()
- Gets the locale of this component.
- Returns:
- This component's locale. If this component does not have a locale, the locale of its parent is returned.
- Throws:
IllegalComponentStateException
- If the Component does not have its own locale and has not yet been added to a containment hierarchy such that the locale can be determined from the containing parent.
- Since:
- JDK1.1
- See Also:
- #setLocale
setLocale
public void setLocale(Locale l)
- Sets the locale of this component.
- Parameters:
l
- The locale to become this component's locale.
- Since:
- JDK1.1
- See Also:
- #getLocale
getColorModel
public ColorModel getColorModel()
- Gets the instance of
ColorModel
used to display the component on the output device.
- Returns:
- The color model used by this component.
- Since:
- JDK1.0
- See Also:
- java.awt.image.ColorModel
- java.awt.peer.ComponentPeer#getColorModel()
- java.awt.Toolkit#getColorModel()
getLocation
public Point getLocation()
- Gets the location of this component in the form of a point specifying the component's top-left corner. The location will be relative to the parent's coordinate space.
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.
- Returns:
- An instance of
Point
representing the top-left corner of the component's bounds in the coordinate space of the component's parent.
- Since:
- JDK1.1
- See Also:
- #setLocation
- #getLocationOnScreen
getLocationOnScreen
public 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.
- Returns:
- An instance of
Point
representing the top-left corner of the component's bounds in the coordinate space of the screen.
- See Also:
- #setLocation
- #getLocation
location
public Point location()
- Deprecated. As of JDK version 1.1, replaced by
getLocation()
.
setLocation
public void setLocation(int x,
int y)
- Moves this component to a new location. The top-left corner of the new location is specified by the
x
and y
parameters in the coordinate space of this component's parent.
- Parameters:
x
- The x-coordinate of the new location's top-left corner in the parent's coordinate space.
y
- The y-coordinate of the new location's top-left corner in the parent's coordinate space.
- Since:
- JDK1.1
- See Also:
- #getLocation
- #setBounds
move
public void move(int x,
int y)
- Deprecated. As of JDK version 1.1, replaced by
setLocation(int, int)
.
setLocation
public void setLocation(Point p)
- Moves this component to a new location. The top-left corner of the new location is specified by point
p
. Point p
is given in the parent's coordinate space.
- Parameters:
p
- The point defining the top-left corner of the new location, given in the coordinate space of this component's parent.
- Since:
- JDK1.1
- See Also:
- #getLocation
- #setBounds
getSize
public Dimension getSize()
- Returns the size of this component in the form of a
Dimension
object. The height
field of the Dimension
object contains this component's height, and the width
field of the Dimension
object contains this component's width.
- Returns:
- A
Dimension
object that indicates the size of this component.
- Since:
- JDK1.1
- See Also:
- #setSize
size
public Dimension size()
- Deprecated. As of JDK version 1.1, replaced by
getSize()
.
setSize
public void setSize(int width,
int height)
- Resizes this component so that it has width
width
and height
.
- Parameters:
width
- The new width of this component in pixels.
height
- The new height of this component in pixels.
- Since:
- JDK1.1
- See Also:
- #getSize
- #setBounds
resize
public void resize(int width,
int height)
- Deprecated. As of JDK version 1.1, replaced by
setSize(int, int)
.
setSize
public void setSize(Dimension d)
- Resizes this component so that it has width
d.width
and height d.height
.
- Parameters:
d
- The dimension specifying the new size of this component.
- Since:
- JDK1.1
- See Also:
- #setSize
- #setBounds
resize
public void resize(Dimension d)
- Deprecated. As of JDK version 1.1, replaced by
setSize(Dimension)
.
getBounds
public Rectangle getBounds()
- Gets the bounds of this component in the form of a
Rectangle
object. The bounds specify this component's width, height, and location relative to its parent.
- Returns:
- A rectangle indicating this component's bounds.
- See Also:
- #setBounds
- #getLocation
- #getSize
bounds
public Rectangle bounds()
- Deprecated. As of JDK version 1.1, replaced by
getBounds()
.
setBounds
public void setBounds(int x,
int y,
int width,
int height)
- Moves and resizes this component. The new location of the top-left corner is specified by
x
and y
, and the new size is specified by width
and height
.
- Parameters:
x
- The new x-coordinate of this component.
y
- The new y-coordinate of this component.
width
- The new width
of this component.
height
- The new height
of this component.
- See Also:
- java.awt.Component#getBounds
- java.awt.Component#setLocation(int, int)
- java.awt.Component#setLocation(java.awt.Point)
- java.awt.Component#setSize(int, int)
- java.awt.Component#setSize(java.awt.Dimension)
reshape
public void reshape(int x,
int y,
int width,
int height)
- Deprecated. As of JDK version 1.1, replaced by
setBounds(int, int, int, int)
.
setBounds
public void setBounds(Rectangle r)
- Moves and resizes this component to conform to the new bounding rectangle
r
. This component's new position is specified by r.x
and r.y
, and its new size is specified by r.width
and r.height
- Parameters:
r
- The new bounding rectangle for this component.
- Since:
- JDK1.1
- See Also:
- java.awt.Component#getBounds
- java.awt.Component#setLocation(int, int)
- java.awt.Component#setLocation(java.awt.Point)
- java.awt.Component#setSize(int, int)
- java.awt.Component#setSize(java.awt.Dimension)
getX
public int getX()
- Return the current x coordinate of the components origin. This method is preferable to writing component.getBounds().x, or component.getLocation().x because it doesn't cause any heap allocations.
- Returns:
- the current x coordinate of the components origin.
- Since:
- 1.2
getY
public int getY()
- Return the current y coordinate of the components origin. This method is preferable to writing component.getBounds().y, or component.getLocation().y because it doesn't cause any heap allocations.
- Returns:
- the current y coordinate of the components origin.
- Since:
- 1.2
getWidth
public int getWidth()
- Return the current width of this component. This method is preferable to writing component.getBounds().width, or component.getSize().width because it doesn't cause any heap allocations.
- Returns:
- the current width of this component.
- Since:
- 1.2
getHeight
public int getHeight()
- Return the current height of this component. This method is preferable to writing component.getBounds().height, or component.getSize().height because it doesn't cause any heap allocations.
- Returns:
- the current height of this component.
- Since:
- 1.2
getBounds
public Rectangle getBounds(Rectangle rv)
- Store the bounds of this component into "return value" rv and return rv. If rv is null a new Rectangle is allocated. This version of getBounds() is useful if the caller wants to avoid allocating a new Rectangle object on the heap.
- Parameters:
rv
- the return value, modified to the components bounds
- Returns:
- rv
getSize
public Dimension getSize(Dimension rv)
- Store the width/height of this component into "return value" rv and return rv. If rv is null a new Dimension object is allocated. This version of getSize() is useful if the caller wants to avoid allocating a new Dimension object on the heap.
- Parameters:
rv
- the return value, modified to the components size
- Returns:
- rv
getLocation
public Point getLocation(Point rv)
- Store the x,y origin of this component into "return value" rv and return rv. If rv is null a new Point is allocated. This version of getLocation() is useful if the caller wants to avoid allocating a new Point object on the heap.
- Parameters:
rv
- the return value, modified to the components location
- Returns:
- rv
isOpaque
public boolean isOpaque()
- Returns true if this component is completely opaque, returns false by default.
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:
- #isLightweight
isLightweight
public boolean isLightweight()
- A lightweight component doesn't have a native toolkit peer. Subclasses of Component and Container, other than the ones defined in this package like Button or Scrollbar, are lightweight. All of the Swing components are lightweights. 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:
- #isDisplayable
getPreferredSize
public Dimension getPreferredSize()
- Gets the preferred size of this component.
- Returns:
- A dimension object indicating this component's preferred size.
- See Also:
- #getMinimumSize
- java.awt.LayoutManager
preferredSize
public Dimension preferredSize()
- Deprecated. As of JDK version 1.1, replaced by
getPreferredSize()
.
getMinimumSize
public Dimension getMinimumSize()
- Gets the mininimum size of this component.
- Returns:
- A dimension object indicating this component's minimum size.
- See Also:
- #getPreferredSize
- java.awtLayoutManager
minimumSize
public Dimension minimumSize()
- Deprecated. As of JDK version 1.1, replaced by
getMinimumSize()
.
getMaximumSize
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
getAlignmentX
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.
getAlignmentY
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.
doLayout
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
layout
public void layout()
- Deprecated. As of JDK version 1.1, replaced by
doLayout()
.
validate
public void validate()
- Ensures that this component has a valid layout. This method is primarily intended to operate on instances of
Container
.
- Since:
- JDK1.0
- See Also:
- java.awt.Component#invalidate
- java.awt.Component#doLayout()
- java.awt.LayoutManager
- java.awt.Container#validate
invalidate
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.
- Since:
- JDK1.0
- See Also:
- java.awt.Component#validate
- java.awt.Component#doLayout
- java.awt.LayoutManager
getGraphics
public Graphics getGraphics()
- Creates a graphics context for this component. This method will return
null
if this component is currently not displayable.
- Returns:
- A graphics context for this component, or
null
if it has none.
- Since:
- JDK1.0
- See Also:
- java.awt.Component#paint
getFontMetrics
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
.
- the font metrics for the specified font.
- Since:
- JDK1.0
- See Also:
- java.awt.Component#getFont
- java.awt.Component#getPeer()
- java.awt.peer.ComponentPeer#getFontMetrics(java.awt.Font)
- java.awt.Toolkit#getFontMetrics(java.awt.Font)
setCursor
public void setCursor(Cursor cursor)
- Sets the cursor image to the specified cursor. This cursor image is displayed when the
contains
method for this component returns true for the current cursor location, and this Component is visible, displayable, and enabled. Setting the cursor of a Container
causes that cursor to be displayed within all of the container's subcomponents, except for those that have a non-null 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.
- Since:
- JDK1.1
- See Also:
- #isEnabled
- #isShowing
- java.awt.Component#getCursor
- java.awt.Component#contains
- java.awt.Toolkit#createCustomCursor
- java.awt.Cursor
getCursor
public Cursor getCursor()
- Gets the cursor set in the component. If the component does not have a cursor set, the cursor of its parent is returned. If no Cursor is set in the entire hierarchy, Cursor.DEFAULT_CURSOR is returned.
- Since:
- JDK1.1
- See Also:
- #setCursor
paint
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. For performance reasons, Components with zero width or height aren't considered to need painting when they are first shown, and also aren't considered to need repair.
- Parameters:
g
- The graphics context to use for painting.
- Since:
- JDK1.0
- See Also:
- java.awt.Component#update
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 update
method 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.
- Since:
- JDK1.0
- See Also:
- java.awt.Component#paint
- java.awt.Component#repaint()
paintAll
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.
- Since:
- JDK1.0
- See Also:
- java.awt.Component#paint
lightweightPaint
void lightweightPaint(Graphics g)
- Simulates the peer callbacks into java.awt for painting of lightweight Components.
- Parameters:
g
- the graphics context to use for painting.
- See Also:
- #paintAll
paintHeavyweightComponents
void paintHeavyweightComponents(Graphics g)
- Paints all the heavyweight subcomponents.
repaint
public void repaint()
- Repaints this component.
This method causes a call to this component's update
method as soon as possible.
- Since:
- JDK1.0
- See Also:
- java.awt.Component#update(java.awt.Graphics)
repaint
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
- Since:
- JDK1.0
- See Also:
- #paint
- java.awt.Component#update(java.awt.Graphics)
repaint
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.
- Since:
- JDK1.0
- See Also:
- java.awt.Component#update(java.awt.Graphics)
repaint
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.
- Since:
- JDK1.0
- See Also:
- java.awt.Component#update(java.awt.Graphics)
print
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.
- Since:
- JDK1.0
- See Also:
- java.awt.Component#paint(java.awt.Graphics)
printAll
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.
- Since:
- JDK1.0
- See Also:
- java.awt.Component#print(java.awt.Graphics)
lightweightPrint
void lightweightPrint(Graphics g)
- Simulates the peer callbacks into java.awt for printing of lightweight Components.
- Parameters:
g
- the graphics context to use for printing.
- See Also:
- #printAll
printHeavyweightComponents
void printHeavyweightComponents(Graphics g)
- Prints all the heavyweight subcomponents.
imageUpdate
public boolean imageUpdate(Image img,
int infoflags,
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.
w
- the width.
h
- the height.
- Returns:
false
if the infoflags indicate that the image is completely loaded; true
otherwise.
- Since:
- JDK1.0
- See Also:
- java.awt.image.ImageObserver
- java.awt.Graphics#drawImage(java.awt.Image, int, int, java.awt.Color, java.awt.image.ImageObserver)
- java.awt.Graphics#drawImage(java.awt.Image, int, int, java.awt.image.ImageObserver)
- java.awt.Graphics#drawImage(java.awt.Image, int, int, int, int, java.awt.Color, java.awt.image.ImageObserver)
- java.awt.Graphics#drawImage(java.awt.Image, int, int, int, int, java.awt.image.ImageObserver)
- java.awt.image.ImageObserver#imageUpdate(java.awt.Image, int, int, int, int, int)
createImage
public Image createImage(ImageProducer producer)
- Creates an image from the specified image producer.
- Parameters:
producer
- the image producer
- Returns:
- the image produced.
- Since:
- JDK1.0
createImage
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.
- Since:
- JDK1.0
prepareImage
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.
- Since:
- JDK1.0
prepareImage
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.
- Since:
- JDK1.0
- See Also:
- java.awt.image.ImageObserver
checkImage
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.
- Since:
- JDK1.0
- See Also:
- java.awt.Component#prepareImage(java.awt.Image, int, int, java.awt.image.ImageObserver)
- java.awt.Toolkit#checkImage(java.awt.Image, int, int, java.awt.image.ImageObserver)
- java.awt.image.ImageObserver
checkImage
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.
- Since:
- JDK1.0
- See Also:
- java.awt.Component#prepareImage(java.awt.Image, int, int, java.awt.image.ImageObserver)
- java.awt.Toolkit#checkImage(java.awt.Image, int, int, java.awt.image.ImageObserver)
- java.awt.image.ImageObserver
contains
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.
- Since:
- JDK1.1
- See Also:
- java.awt.Component#getComponentAt(int, int)
inside
public boolean inside(int x,
int y)
- Deprecated. As of JDK version 1.1, replaced by contains(int, int).
contains
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.
- Since:
- JDK1.1
- See Also:
- java.awt.Component#getComponentAt(java.awt.Point)
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.
- Since:
- JDK1.0
- See Also:
- java.awt.Component#contains(int, int)
locate
public Component locate(int x,
int y)
- Deprecated. As of JDK version 1.1, replaced by getComponentAt(int, int).
getComponentAt
public Component getComponentAt(Point p)
- Returns the component or subcomponent that contains the specified point.
- Parameters:
p
- the point.
- Since:
- JDK1.1
- See Also:
- java.awt.Component#contains
deliverEvent
public void deliverEvent(Event e)
- Deprecated. As of JDK version 1.1, replaced by
dispatchEvent(AWTEvent e)
.
dispatchEvent
public final void dispatchEvent(AWTEvent e)
- Dispatches an event to this component or one of its sub components. Calls processEvent() before returning for 1.1-style events which have been enabled for the Component.
- Parameters:
e
- the event
getWindowForObject
private Window getWindowForObject(Object obj)
- Returns the Window subclass that contains this object. Will return the object itself, if it is a window.
postEvent
public boolean postEvent(Event e)
- Deprecated. As of JDK version 1.1, replaced by dispatchEvent(AWTEvent).
addComponentListener
public synchronized void addComponentListener(ComponentListener l)
- Adds the specified component listener to receive component events from this component. If l is null, no exception is thrown and no action is performed.
- Parameters:
l
- the component listener.
- Since:
- JDK1.1
- See Also:
- java.awt.event.ComponentEvent
- java.awt.event.ComponentListener
- java.awt.Component#removeComponentListener
removeComponentListener
public synchronized void removeComponentListener(ComponentListener l)
- Removes the specified component listener so that it no longer receives component events from this component. This method performs no function, nor does it throw an exception, if the listener specified by the argument was not previously added to this component. If l is null, no exception is thrown and no action is performed.
- Parameters:
l
- the component listener.
- Since:
- JDK1.1
- See Also:
- java.awt.event.ComponentEvent
- java.awt.event.ComponentListener
- java.awt.Component#addComponentListener
addFocusListener
public synchronized void addFocusListener(FocusListener l)
- Adds the specified focus listener to receive focus events from this component when this component gains input focus. If l is null, no exception is thrown and no action is performed.
- Parameters:
l
- the focus listener.
- Since:
- JDK1.1
- See Also:
- java.awt.event.FocusEvent
- java.awt.event.FocusListener
- java.awt.Component#removeFocusListener
removeFocusListener
public synchronized void removeFocusListener(FocusListener l)
- Removes the specified focus listener so that it no longer receives focus events from this component. This method performs no function, nor does it throw an exception, if the listener specified by the argument was not previously added to this component. If l is null, no exception is thrown and no action is performed.
- Parameters:
l
- the focus listener.
- Since:
- JDK1.1
- See Also:
- java.awt.event.FocusEvent
- java.awt.event.FocusListener
- java.awt.Component#addFocusListener
addHierarchyListener
public 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. If l is null, no exception is thrown and no action is performed.
- Parameters:
l
- the hierarchy listener.
- Since:
- 1.3
- See Also:
- java.awt.event.HierarchyEvent
- java.awt.event.HierarchyListener
- java.awt.Component#removeHierarchyListener
removeHierarchyListener
public void removeHierarchyListener(HierarchyListener l)
- Removes the specified hierarchy listener so that it no longer receives hierarchy changed events from this component. This method performs no function, nor does it throw an exception, if the listener specified by the argument was not previously added to this component. If l is null, no exception is thrown and no action is performed.
- Parameters:
l
- the hierarchy listener.
- Since:
- 1.3
- See Also:
- java.awt.event.HierarchyEvent
- java.awt.event.HierarchyListener
- java.awt.Component#addHierarchyListener
addHierarchyBoundsListener
public 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. If l is null, no exception is thrown and no action is performed.
- Parameters:
l
- the hierarchy bounds listener.
- Since:
- 1.3
- See Also:
- java.awt.event.HierarchyEvent
- java.awt.event.HierarchyBoundsListener
- java.awt.Component#removeHierarchyBoundsListener
removeHierarchyBoundsListener
public void removeHierarchyBoundsListener(HierarchyBoundsListener l)
- Removes the specified hierarchy bounds listener so that it no longer receives hierarchy bounds events from this component. This method performs no function, nor does it throw an exception, if the listener specified by the argument was not previously added to this component. If l is null, no exception is thrown and no action is performed.
- Parameters:
l
- the hierarchy bounds listener.
- Since:
- 1.3
- See Also:
- java.awt.event.HierarchyEvent
- java.awt.event.HierarchyBoundsListener
- java.awt.Component#addHierarchyBoundsListener
addKeyListener
public synchronized void addKeyListener(KeyListener l)
- Adds the specified key listener to receive key events from this component. If l is null, no exception is thrown and no action is performed.
- Parameters:
l
- the key listener.
- Since:
- JDK1.1
- See Also:
- java.awt.event.KeyEvent
- java.awt.event.KeyListener
- java.awt.Component#removeKeyListener
removeKeyListener
public synchronized void removeKeyListener(KeyListener l)
- Removes the specified key listener so that it no longer receives key events from this component. This method performs no function, nor does it throw an exception, if the listener specified by the argument was not previously added to this component. If l is null, no exception is thrown and no action is performed.
- Parameters:
l
- the key listener.
- Since:
- JDK1.1
- See Also:
- java.awt.event.KeyEvent
- java.awt.event.KeyListener
- java.awt.Component#addKeyListener
addMouseListener
public synchronized void addMouseListener(MouseListener l)
- Adds the specified mouse listener to receive mouse events from this component. If l is null, no exception is thrown and no action is performed.
- Parameters:
l
- the mouse listener.
- Since:
- JDK1.1
- See Also:
- java.awt.event.MouseEvent
- java.awt.event.MouseListener
- java.awt.Component#removeMouseListener
removeMouseListener
public synchronized void removeMouseListener(MouseListener l)
- Removes the specified mouse listener so that it no longer receives mouse events from this component. This method performs no function, nor does it throw an exception, if the listener specified by the argument was not previously added to this component. If l is null, no exception is thrown and no action is performed.
- Parameters:
l
- the mouse listener.
- Since:
- JDK1.1
- See Also:
- java.awt.event.MouseEvent
- java.awt.event.MouseListener
- java.awt.Component#addMouseListener
addMouseMotionListener
public synchronized void addMouseMotionListener(MouseMotionListener l)
- Adds the specified mouse motion listener to receive mouse motion events from this component. If l is null, no exception is thrown and no action is performed.
- Parameters:
l
- the mouse motion listener.
- Since:
- JDK1.1
- See Also:
- java.awt.event.MouseMotionEvent
- java.awt.event.MouseMotionListener
- java.awt.Component#removeMouseMotionListener
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. This method performs no function, nor does it throw an exception, if the listener specified by the argument was not previously added to this component. If l is null, no exception is thrown and no action is performed.
- Parameters:
l
- the mouse motion listener.
- Since:
- JDK1.1
- See Also:
- java.awt.event.MouseMotionEvent
- java.awt.event.MouseMotionListener
- java.awt.Component#addMouseMotionListener
addInputMethodListener
public synchronized void addInputMethodListener(InputMethodListener l)
- Adds the specified input method listener to receive input method events from this component. A component will only receive input method events from input methods if it also overrides getInputMethodRequests to return an InputMethodRequests instance. If l is null, no exception is thrown and no action is performed.
- Parameters:
l
- the input method listener.
- Since:
- 1.2
- See Also:
- java.awt.event.InputMethodEvent
- java.awt.event.InputMethodListener
- java.awt.Component#removeInputMethodListener
- java.awt.Component#getInputMethodRequests
removeInputMethodListener
public synchronized void removeInputMethodListener(InputMethodListener l)
- Removes the specified input method listener so that it no longer receives input method events from this component. This method performs no function, nor does it throw an exception, if the listener specified by the argument was not previously added to this component. If l is null, no exception is thrown and no action is performed.
- Parameters:
l
- the input method listener.
- Since:
- 1.2
- See Also:
- java.awt.event.InputMethodEvent
- java.awt.event.InputMethodListener
- java.awt.Component#addInputMethodListener
getListeners
public EventListener[] getListeners(Class listenerType)
- Return an array of all the listeners that were added to the Component with addXXXListener(), where XXX is the name of the
listenerType
argument. For example, to get all of the MouseListeners for the given Component c
, one would write:
MouseListener[] mls = (MouseListener[])(c.getListeners(MouseListener.class))
If no such listener list exists, then an empty array is returned.
- Parameters:
listenerType
- Type of listeners requested. This parameter must be a java.util.EventListener or subclass.
- Returns:
- an array of all listeners added to this Component using addXXXListener, or an empty array if no such listeners have been added to this Component.
- Throws:
ClassCastException
- if the listenerType parameter is not a java.util.EventListener or subclass.
- Since:
- 1.3
getInputMethodRequests
public InputMethodRequests getInputMethodRequests()
- Gets the input method request handler which supports requests from input methods for this component. A component that supports on-the-spot text input must override this method to return an InputMethodRequests instance. At the same time, it also has to handle input method events.
- Returns:
- the input method request handler for this component, null by default.
- Since:
- 1.2
- See Also:
- #addInputMethodListener
getInputContext
public InputContext getInputContext()
- Gets the input context used by this component for handling the communication with input methods when text is entered in this component. By default, the input context used for the parent component is returned. Components may override this to return a private input context.
- Returns:
- The input context used by this component. Null if no context can be determined.
- Since:
- 1.2
enableEvents
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.
- Since:
- JDK1.1
- See Also:
- java.awt.Component#processEvent
- java.awt.Component#disableEvents
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
- Since:
- JDK1.1
- See Also:
- java.awt.Component#enableEvents
coalesceEvents
protected AWTEvent coalesceEvents(AWTEvent existingEvent,
AWTEvent newEvent)
- Potentially coalesce an event being posted with an existing event. This method is called by EventQueue.postEvent if an event with the same ID as the event to be posted is found in the queue (both events must have this component as their source). This method either returns a coalesced event which replaces the existing event (and the new event is then discarded), or null to indicate that no combining should be done (add the second event to the end of the queue). Either event parameter may be modified and returned, as the other one is discarded unless null is returned.
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 Event is always returned.
- Parameters:
existingEvent
- the event already on the EventQueue.
newEvent
- the event being posted to the EventQueue.
- Returns:
- a coalesced event, or null indicating that no coalescing was done.
processEvent
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.
- Since:
- JDK1.1
- See Also:
- java.awt.Component#processComponentEvent
- java.awt.Component#processFocusEvent
- java.awt.Component#processKeyEvent
- java.awt.Component#processMouseEvent
- java.awt.Component#processMouseMotionEvent
- java.awt.Component#processInputMethodEvent
- java.awt.Component#processHierarchyEvent
processComponentEvent
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.
- Since:
- JDK1.1
- See Also:
- java.awt.event.ComponentEvent
- java.awt.event.ComponentListener
- java.awt.Component#addComponentListener
- java.awt.Component#enableEvents
processFocusEvent
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.
- Since:
- JDK1.1
- See Also:
- java.awt.event.FocusEvent
- java.awt.event.FocusListener
- java.awt.Component#addFocusListener
- java.awt.Component#enableEvents
processKeyEvent
protected void processKeyEvent(KeyEvent e)
- Processes key events occurring on this component by dispatching them to any registered
KeyListener
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.
- Since:
- JDK1.1
- See Also:
- java.awt.event.KeyEvent
- java.awt.event.KeyListener
- java.awt.Component#addKeyListener
- java.awt.Component#enableEvents
processMouseEvent
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.
- Since:
- JDK1.1
- See Also:
- java.awt.event.MouseEvent
- java.awt.event.MouseListener
- java.awt.Component#addMouseListener
- java.awt.Component#enableEvents
processMouseMotionEvent
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.
- Since:
- JDK1.1
- See Also:
- java.awt.event.MouseMotionEvent
- java.awt.event.MouseMotionListener
- java.awt.Component#addMouseMotionListener
- java.awt.Component#enableEvents
processInputMethodEvent
protected void processInputMethodEvent(InputMethodEvent e)
- Processes input method events occurring on this component by dispatching them to any registered
InputMethodListener
objects. 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
.
- Parameters:
e
- the input method event
- Since:
- 1.2
- See Also:
- java.awt.event.InputMethodEvent
- java.awt.event.InputMethodListener
- java.awt.Component#addInputMethodListener
- java.awt.Component#enableEvents
processHierarchyEvent
protected void processHierarchyEvent(HierarchyEvent e)
- Processes hierarchy events occurring on this component by dispatching them to any registered
HierarchyListener
objects. 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
.
- Parameters:
e
- the hierarchy event
- Since:
- 1.3
- See Also:
- java.awt.event.HierarchyEvent
- java.awt.event.HierarchyListener
- java.awt.Component#addHierarchyListener
- java.awt.Component#enableEvents
processHierarchyBoundsEvent
protected void processHierarchyBoundsEvent(HierarchyEvent e)
- Processes hierarchy bounds events occurring on this component by dispatching them to any registered
HierarchyBoundsListener
objects. 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
.
- Parameters:
e
- the hierarchy event
- Since:
- 1.3
- See Also:
- java.awt.event.HierarchyEvent
- java.awt.event.HierarchyBoundsListener
- java.awt.Component#addHierarchyBoundsListener
- java.awt.Component#enableEvents
handleEvent
public boolean handleEvent(Event evt)
- Deprecated. As of JDK version 1.1 replaced by processEvent(AWTEvent).
mouseDown
public boolean mouseDown(Event evt,
int x,
int y)
- Deprecated. As of JDK version 1.1, replaced by processMouseEvent(MouseEvent).
mouseDrag
public boolean mouseDrag(Event evt,
int x,
int y)
- Deprecated. As of JDK version 1.1, replaced by processMouseMotionEvent(MouseEvent).
mouseUp
public boolean mouseUp(Event evt,
int x,
int y)
- Deprecated. As of JDK version 1.1, replaced by processMouseEvent(MouseEvent).
mouseMove
public boolean mouseMove(Event evt,
int x,
int y)
- Deprecated. As of JDK version 1.1, replaced by processMouseMotionEvent(MouseEvent).
mouseEnter
public boolean mouseEnter(Event evt,
int x,
int y)
- Deprecated. As of JDK version 1.1, replaced by processMouseEvent(MouseEvent).
mouseExit
public boolean mouseExit(Event evt,
int x,
int y)
- Deprecated. As of JDK version 1.1, replaced by processMouseEvent(MouseEvent).
keyDown
public boolean keyDown(Event evt,
int key)
- Deprecated. As of JDK version 1.1, replaced by processKeyEvent(KeyEvent).
keyUp
public boolean keyUp(Event evt,
int key)
- Deprecated. As of JDK version 1.1, replaced by processKeyEvent(KeyEvent).
action
public 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.
addNotify
public void addNotify()
- Makes this Component displayable by connecting it to a native screen resource. This method is called internally by the toolkit and should not be called directly by programs.
- Since:
- JDK1.0
- See Also:
- java.awt.Component#isDisplayable
- java.awt.Component#removeNotify
removeNotify
public void removeNotify()
- Makes this Component undisplayable by destroying it native screen resource. This method is called by the toolkit internally and should not be called directly by programs.
- Since:
- JDK1.0
- See Also:
- java.awt.Component#isDisplayable
- java.awt.Component#addNotify
gotFocus
public boolean gotFocus(Event evt,
Object what)
- Deprecated. As of JDK version 1.1, replaced by processFocusEvent(FocusEvent).
lostFocus
public boolean lostFocus(Event evt,
Object what)
- Deprecated. As of JDK version 1.1, replaced by processFocusEvent(FocusEvent).
isFocusTraversable
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.
- Since:
- JDK1.1
requestFocus
public void requestFocus()
- Requests that this component get the input focus. The component must be visible on the screen for this request to be granted
- Since:
- JDK1.0
- See Also:
- FocusEvent
- #addFocusListener
- #processFocusEvent
- #isFocusTraversable
transferFocus
public void transferFocus()
- Transfers the focus to the next component.
- Since:
- JDK1.1s
- See Also:
- java.awt.Component#requestFocus
nextFocus
public void nextFocus()
- Deprecated. As of JDK version 1.1, replaced by transferFocus().
hasFocus
public boolean hasFocus()
- Returns true if this Component has the keyboard focus.
- Returns:
- true if this Component has the keyboard focus.
- Since:
- 1.2
add
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.
- Since:
- JDK1.1
- See Also:
- java.awt.Component#remove(java.awt.MenuComponent)
remove
public synchronized void remove(MenuComponent popup)
- Removes the specified popup menu from the component.
- Parameters:
popup
- the popup menu to be removed.
- Since:
- JDK1.1
- See Also:
- java.awt.Component#add(java.awt.PopupMenu)
paramString
protected String paramString()
- Returns a string representing the state of this component. 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
.
- Returns:
- a string representation of this component's state.
- Since:
- JDK1.0
toString
public String toString()
- Returns a string representation of this component and its values.
- Returns:
- a string representation of this component.
- Since:
- JDK1.0
list
public void list()
- Prints a listing of this component to the standard system output stream
System.out
.
- Since:
- JDK1.0
- See Also:
- java.lang.System#out
list
public void list(PrintStream out)
- Prints a listing of this component to the specified output stream.
- Parameters:
out
- a print stream.
- Since:
- JDK1.0
list
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.
- Since:
- JDK1.0
- See Also:
- java.io.PrintStream#println(java.lang.Object)
list
public void list(PrintWriter out)
- Prints a listing to the specified print writer.
- Parameters:
out
- The print writer to print to.
- Since:
- JDK1.1
list
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.
- Since:
- JDK1.1
- See Also:
- java.io.PrintStream#println(java.lang.Object)
addPropertyChangeListener
public synchronized void addPropertyChangeListener(PropertyChangeListener listener)
- Add a PropertyChangeListener to the listener list. The listener is registered for all properties.
A PropertyChangeEvent will get fired in response to an explicit setFont, setBackground, or SetForeground on the current component. Note that if the current component is inheriting its foreground, background, or font from its container, then no event will be fired in response to a change in the inherited property. If listener is null, no exception is thrown and no action is performed.
- Parameters:
listener
- The PropertyChangeListener to be added
removePropertyChangeListener
public synchronized void removePropertyChangeListener(PropertyChangeListener listener)
- Remove a PropertyChangeListener from the listener list. This removes a PropertyChangeListener that was registered for all properties. If listener is null, no exception is thrown and no action is performed.
- Parameters:
listener
- The PropertyChangeListener to be removed
addPropertyChangeListener
public synchronized void addPropertyChangeListener(String propertyName,
PropertyChangeListener listener)
- Add a PropertyChangeListener for a specific property. The listener will be invoked only when a call on firePropertyChange names that specific property. If listener is null, no exception is thrown and no action is performed.
- Parameters:
propertyName
- The name of the property to listen on.
listener
- The PropertyChangeListener to be added
removePropertyChangeListener
public synchronized void removePropertyChangeListener(String propertyName,
PropertyChangeListener listener)
- Remove a PropertyChangeListener for a specific property. If listener is null, no exception is thrown and no action is performed.
- Parameters:
propertyName
- The name of the property that was listened on.
listener
- The PropertyChangeListener to be removed
firePropertyChange
protected void firePropertyChange(String propertyName,
Object oldValue,
Object newValue)
- Support for reporting bound property changes. This method can be called when a bound property has changed and it will send the appropriate PropertyChangeEvent to any registered PropertyChangeListeners.
writeObject
private void writeObject(ObjectOutputStream s)
- Writes default serializable fields to stream. Writes a list of serializable ItemListener(s) as optional data. The non-serializable ItemListener(s) are detected and no attempt is made to serialize them.
- See Also:
- AWTEventMulticaster.save(ObjectOutputStream, String, EventListener)
- java.awt.Component.itemListenerK
readObject
private void readObject(ObjectInputStream s)
- Read the ObjectInputStream and if it isnt null add a listener to receive item events fired by the components. Unrecognised keys or values will be Ignored.
- See Also:
- removeActionListener()
- addActionListener()
setComponentOrientation
public void setComponentOrientation(ComponentOrientation o)
- Set the language-sensitive orientation that is to be used to order the elements or text within this component. Language-sensitive LayoutManager and Component subclasses will use this property to determine how to lay out and draw components.
At construction time, a component's orientation is set to ComponentOrientation.UNKNOWN, indicating that it has not been specified explicitly. The UNKNOWN orientation behaves the same as ComponentOrientation.LEFT_TO_RIGHT.
To set the orientation of a single component, use this method. To apply a ResourceBundle's orientation to an entire component hierarchy, use java.awt.Window.applyResourceBundle.
- Author:
- Laura Werner, IBM
- See Also:
- java.awt.ComponentOrientation
- java.awt.Window#applyResourceBundle(java.util.ResourceBundle)
getComponentOrientation
public ComponentOrientation getComponentOrientation()
- Retrieve the language-sensitive orientation that is to be used to order the elements or text within this component. LayoutManager and Component subclasses that wish to respect orientation should call this method to get the component's orientation before performing layout or drawing.
- Author:
- Laura Werner, IBM
- See Also:
- java.awt.ComponentOrientation
initIDs
private static native void initIDs()
- Initialize JNI field and method IDs
getAccessibleContext
public AccessibleContext getAccessibleContext()
- Get the AccessibleContext associated with this Component
- Returns:
- the AccessibleContext of this Component
getAccessibleIndexInParent
int getAccessibleIndexInParent()
- Get the index of this object in its accessible parent.
- Returns:
- -1 of this object does not have an accessible parent. Otherwise, the index of the child in its accessible parent.
getAccessibleStateSet
AccessibleStateSet getAccessibleStateSet()
- Get the state of this object.
- Returns:
- an instance of AccessibleStateSet containing the current state set of the object
- See Also:
- AccessibleState