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Class jclass.bwt.JCComponent

java.lang.Object
   |
   +----java.awt.Component
           |
           +----java.awt.Canvas
                   |
                   +----jclass.bwt.JCComponent

public abstract class JCComponent
extends Canvas
The abstract base class for all BWT components.

Methods which may be supplied by a subclass

 drawComponent (mandatory)
 preferredWidth
 preferredHeight
 reshape
 

Properties

Name Method
Background setBackground
DoubleBuffer setDoubleBuffer
Font setFont
Foreground setForeground
HighlightColor setHighlightColor
HighlightThickness setHighlightThickness
Insets setInsets
PreferredSize setPreferredSize
ShadowThickness setShadowThickness
Traversable setTraversable
UserData setUserData


Variable Index

 o applet
The parent applet.
 o applet_context
The current context.
 o dblbuffer_image
Current double-buffer image.
 o draw_gc
The instance passed to paint().
 o highlight
Highlight thickness.
 o in_repaint
In repaint() ?
 o needs_layout
Needs layout?
 o shadow
Shadow thickness.
 o shadow_type
Shadow type.
 o use_system_colors
 o version

Constructor Index

 o JCComponent()
Creates a component.
 o JCComponent(Applet, String)
Creates a component which reads parameters from the applet's HTML file.

Method Index

 o addNotify()
Creates the peer of the canvas.
 o createImage(int, int)
Creates an off-screen drawable Image to be used for double buffering.
 o disable()
Disables the component.
 o drawHighlight(boolean)
Draws or clears the highlight rectangle (called by gotFocus).
 o drawHighlight(Graphics, boolean)
Draws or clears the highlight rectangle (called by paint).
 o drawShadow(Graphics)
Draws the shadow (called by paint).
 o enable()
Enables the component.
 o enable11Events(long)
For JDK1.1, calls Component.enableEvents (which is final).
 o fillBackground(Graphics)
Fills the component with the background color (called by paint).
 o getAppletContext()
Gets the component's applet's context.
 o getConverter()
Gets the converter used for converting strings to internal values.
 o getDoubleBuffer()
Gets the component's DoubleBuffer value.
 o getDoubleBufferGraphics()
Creates a double-buffer image, for subsequent retrieval via getDoubleBufferImage
 o getDoubleBufferImage()
Returns the double-buffer image previously created in a call to getDoubleBufferGraphics.
 o getDrawingArea()
Gets the bounding rectangle of the component's drawing area, (its area minus the shadows and insets).
 o getDrawingArea(Rectangle)
Gets the bounding rectangle of the component's drawing area, (its area minus the shadows and insets).
 o getDrawingAreaHeight()
Gets the bounding rectangle's height of the component's drawing area, (its area minus the shadows and insets).
 o getDrawingAreaWidth()
Gets the bounding rectangle's width of the component's drawing area, (its area minus the shadows and insets).
 o getFrame()
Gets the parent frame.
 o getHighlightColor()
Gets the color of the highlight rectangle.
 o getHighlightThickness()
Gets the thickness of the highlight rectangle.
 o getInsets()
Returns the previously set insets.
 o getPaintRect()
Returns the area currently being painted, relative to the component's origin.
 o getParameters()
Reads the parameter values from the HTML page using the component's applet.
 o getParameters(Applet)
Reads the parameter values from the HTML page using the specified applet.
 o getParameters(Applet, String)
Reads the parameter values from the file.
 o getShadowThickness()
Gets the shadow's thickness.

HTML param name/value: "ShadowThickness"/int

 o getUserData()
Gets the userdata value.
 o getUserDataInt()
Gets the userdata value as an int.
 o gotFocus(Event, Object)
Called when the component receives keyboard focus.
 o hasFocus()
Returns true if this component has keyboard focus.
 o insets()
Returns the previously set insets.
 o isFocusTraversable()
Returns whether this component can be traversed using Tab or Shift-Tab keyboard focus traversal.
 o isTraversable()
Returns true if the component can accept focus - it must be traversable, showing, and enabled.
 o layout()
Lays out the component's internal elements.
 o lostFocus(Event, Object)
Called when the component loses keyboard focus.
 o minimumSize()
Returns preferredSize().
 o mouseDown(Event, int, int)
If btn1 is pressed and the component is traversable, requestFocus is called.
 o paint(Graphics)
An internal method used to handle repaint events.
 o paintComponent(Graphics)
Called by paint.
 o preferredHeight()
Gets the subclass' preferred height (default: 100).
 o preferredSize()
Returns the preferred size of this component.
 o preferredWidth()
Gets the subclass' preferred width (default: 100).
 o printAll(Graphics)
Disables double-buffering, and calls Container.printAll
 o processFocusEvent(FocusEvent)
Processes focus events occurring on this component by dispatching them to any registered FocusListener objects.
 o processKeyEvent(KeyEvent)
Processes key events occurring on this component by dispatching them to any registered KeyListener objects.
 o processMouseEvent(MouseEvent)
Processes mouse events occurring on this component by dispatching them to any registered MouseListener objects.
 o processMouseMotionEvent(MouseEvent)
Processes mouse motion events occurring on this component by dispatching them to any registered MouseMotionListener objects.
 o repaint()
Overrides Component.repaint(), which does not always call paint().
 o repaint(int, int, int, int)
Repaints part of the component by calling paint directly.
 o repaint(Rectangle)
Repaints part of the component by calling paint directly.
 o requestFocus()
Requests the input focus.
 o reshape(int, int, int, int)
Reshapes the Component to the specified bounding box.
 o reshape(Rectangle)
Reshapes the Component to the specified bounding box.
 o setBackground(Color)
Sets the background color of the component.

HTML param name/value: "Background"/Color

 o setConverter(JCConverter)
Sets the converter to be used for converting strings to internal values.
 o setCursor(int)
Sets the cursor in the parent frame.
 o setDoubleBuffer(boolean)
Controls whether double-buffering is used when displaying and updating the component (default: true).

HTML param name/value: "DoubleBuffer"/boolean

 o setFont(Font)
Sets the font of the component.

HTML param name/value: "Font"/font

 o setForeground(Color)
Sets the foreground color of the component.

HTML param name/value: "Foreground"/Color

 o setHighlightColor(Color)
Sets the color of the rectangle drawn when the component has focus (default: black).

HTML param name/value: "HighlightColor"/Color

 o setHighlightThickness(int)
Sets the thickness of the rectangle drawn when the component has focus (default: 2).

HTML param name/value: "HighlightThickness"/int

 o setInsets(Insets)
Sets the component's margins (default: 0).

HTML param name/value: "Insets"/Insets

 o setPreferredSize(int, int)
Sets the component's preferred size.
 o setShadowThickness(int)
Sets the shadow's thickness (default: 2)
 o setTraversable(boolean)
Sets whether the component can accept focus (default: true).

HTML param name/value: "Traversable"/boolean

 o setUserData(Object)
Sets an application-defined object that can be attached to the component (default: null).
 o update(Graphics)
Overriden because the default implementation always calls clearRect first, causing unwanted flicker
 o updateParent()
Forces the parent to relayout this component.
 o useSystemColors(boolean)
Specifies that java.awt.SystemColor colors are to be used for new components.
 o validate()
Validates a component.

Variables

 o version
 public static final String version
 o applet
 protected transient Applet applet
The parent applet.

 o applet_context
 protected transient AppletContext applet_context
The current context.

 o in_repaint
 protected transient boolean in_repaint
In repaint() ?

 o needs_layout
 protected transient boolean needs_layout
Needs layout?

 o highlight
 protected int highlight
Highlight thickness.

 o shadow
 protected int shadow
Shadow thickness.

 o shadow_type
 protected int shadow_type
Shadow type.

 o use_system_colors
 protected static boolean use_system_colors
See Also:
useSystemColors
 o draw_gc
 protected transient Graphics draw_gc
The instance passed to paint().

 o dblbuffer_image
 protected transient Image dblbuffer_image
Current double-buffer image.

Constructors

 o JCComponent
 public JCComponent()
Creates a component. No parameters are read from an HTML file.

 o JCComponent
 public JCComponent(Applet applet,
                    String name)
Creates a component which reads parameters from the applet's HTML file.

Parameters:
applet - the applet whose PARAM tags are to be read
name - if this is not null, only parameters preceded by this name are read
See Also:
getParameter

Methods

 o useSystemColors
 public static void useSystemColors(boolean v)
Specifies that java.awt.SystemColor colors are to be used for new components. If false (default), or if running under JDK 1.0, the parent's colors are used.

See Also:
SystemColor
 o getParameters
 protected void getParameters()
Reads the parameter values from the HTML page using the component's applet. The values will override those previously set. Subclasses may override this method to set their own values - in this case, the method should first call super.getParameters().

 o getParameters
 public void getParameters(Applet applet)
Reads the parameter values from the HTML page using the specified applet. The values will override those previously set.

See Also:
getParameter
 o getParameters
 public void getParameters(Applet applet,
                           String file)
Reads the parameter values from the file. The values will override those previously set.

Parameters:
applet - if not null and in a browser, its documentBase() is used to construct a complete filename if necessary
file - if an http protocol is not specified (if a ":" is not present), the current working directory is used
 o setConverter
 public static void setConverter(JCConverter c)
Sets the converter to be used for converting strings to internal values.

See Also:
JCConverter
 o getConverter
 public static JCConverter getConverter()
Gets the converter used for converting strings to internal values.

See Also:
JCConverter
 o setFont
 public synchronized void setFont(Font f)
Sets the font of the component.

HTML param name/value: "Font"/font

Overrides:
setFont in class Component
See Also:
toFont
 o setBackground
 public synchronized void setBackground(Color c)
Sets the background color of the component.

HTML param name/value: "Background"/Color

Overrides:
setBackground in class Component
See Also:
toColor
 o setForeground
 public synchronized void setForeground(Color c)
Sets the foreground color of the component.

HTML param name/value: "Foreground"/Color

Overrides:
setForeground in class Component
See Also:
toColor
 o getShadowThickness
 public int getShadowThickness()
Gets the shadow's thickness.

HTML param name/value: "ShadowThickness"/int

See Also:
setShadowThickness
 o setShadowThickness
 public void setShadowThickness(int v)
Sets the shadow's thickness (default: 2)

 o getHighlightThickness
 public int getHighlightThickness()
Gets the thickness of the highlight rectangle.

See Also:
setHighlightThickness
 o setHighlightThickness
 public synchronized void setHighlightThickness(int v)
Sets the thickness of the rectangle drawn when the component has focus (default: 2).

HTML param name/value: "HighlightThickness"/int

See Also:
toInt
 o getHighlightColor
 public Color getHighlightColor()
Gets the color of the highlight rectangle.

See Also:
setHighlightColor
 o setHighlightColor
 public synchronized void setHighlightColor(Color v)
Sets the color of the rectangle drawn when the component has focus (default: black).

HTML param name/value: "HighlightColor"/Color

See Also:
toColor
 o setInsets
 public synchronized void setInsets(Insets insets)
Sets the component's margins (default: 0).

HTML param name/value: "Insets"/Insets

See Also:
toInsets
 o getDrawingArea
 public Rectangle getDrawingArea()
Gets the bounding rectangle of the component's drawing area, (its area minus the shadows and insets).

See Also:
setInsets
 o getDrawingArea
 public void getDrawingArea(Rectangle rect)
Gets the bounding rectangle of the component's drawing area, (its area minus the shadows and insets).

See Also:
setInsets
 o getDrawingAreaHeight
 public int getDrawingAreaHeight()
Gets the bounding rectangle's height of the component's drawing area, (its area minus the shadows and insets).

See Also:
setInsets
 o getDrawingAreaWidth
 public int getDrawingAreaWidth()
Gets the bounding rectangle's width of the component's drawing area, (its area minus the shadows and insets).

See Also:
setInsets
 o insets
 public Insets insets()
Returns the previously set insets.

See Also:
setInsets
 o getInsets
 public Insets getInsets()
Returns the previously set insets.

See Also:
setInsets
 o getFrame
 public Frame getFrame()
Gets the parent frame.

 o setCursor
 public void setCursor(int cursor)
Sets the cursor in the parent frame.

 o enable
 public synchronized void enable()
Enables the component.

Overrides:
enable in class Component
 o disable
 public synchronized void disable()
Disables the component.

Overrides:
disable in class Component
 o isTraversable
 public boolean isTraversable()
Returns true if the component can accept focus - it must be traversable, showing, and enabled.

See Also:
setTraversable, isEnabled, isShowing
 o isFocusTraversable
 public boolean isFocusTraversable()
Returns whether this component can be traversed using Tab or Shift-Tab keyboard focus traversal.

Overrides:
isFocusTraversable in class Component
See Also:
setTraversable
 o setTraversable
 public void setTraversable(boolean v)
Sets whether the component can accept focus (default: true).

HTML param name/value: "Traversable"/boolean

See Also:
toBoolean
 o getUserData
 public Object getUserData()
Gets the userdata value.

See Also:
setUserData
 o getUserDataInt
 public int getUserDataInt()
Gets the userdata value as an int.

Returns:
0 if no user data has been set.
See Also:
setUserData
 o setUserData
 public void setUserData(Object v)
Sets an application-defined object that can be attached to the component (default: null).

 o layout
 public synchronized void layout()
Lays out the component's internal elements.

Overrides:
layout in class Component
 o reshape
 public synchronized void reshape(Rectangle rect)
Reshapes the Component to the specified bounding box.

 o getDoubleBufferImage
 public Image getDoubleBufferImage()
Returns the double-buffer image previously created in a call to getDoubleBufferGraphics.

See Also:
getDoubleBufferGraphics
 o getDoubleBufferGraphics
 public synchronized Graphics getDoubleBufferGraphics()
Creates a double-buffer image, for subsequent retrieval via getDoubleBufferImage

Returns:
the Graphics instance for the image
See Also:
getDoubleBufferImage
 o repaint
 public synchronized void repaint()
Overrides Component.repaint(), which does not always call paint().

Overrides:
repaint in class Component
 o repaint
 public synchronized void repaint(Rectangle r)
Repaints part of the component by calling paint directly.

 o repaint
 public void repaint(int x,
                     int y,
                     int width,
                     int height)
Repaints part of the component by calling paint directly.

Overrides:
repaint in class Component
 o update
 public void update(Graphics g)
Overriden because the default implementation always calls clearRect first, causing unwanted flicker

Overrides:
update in class Component
 o updateParent
 public void updateParent()
Forces the parent to relayout this component.

 o paintComponent
 protected synchronized void paintComponent(Graphics gc)
Called by paint.

 o fillBackground
 protected void fillBackground(Graphics gc)
Fills the component with the background color (called by paint).

 o drawHighlight
 protected void drawHighlight(boolean on)
Draws or clears the highlight rectangle (called by gotFocus).

Parameters:
on - if true, draws the highlight rectangle; otherwise clears the rect
 o drawHighlight
 protected void drawHighlight(Graphics gc,
                              boolean on)
Draws or clears the highlight rectangle (called by paint).

Parameters:
on - if true, draws the highlight rectangle; otherwise clears the rect
 o drawShadow
 protected void drawShadow(Graphics gc)
Draws the shadow (called by paint).

 o getPaintRect
 public Rectangle getPaintRect()
Returns the area currently being painted, relative to the component's origin.

Returns:
null if no area is being drawn
See Also:
paint
 o paint
 public synchronized void paint(Graphics gc)
An internal method used to handle repaint events. Allocates double buffer image, draws highlight rectangle and shadows, then calls the subclass' paintComponent() method.

Overrides:
paint in class Canvas
See Also:
setDoubleBuffer, fillBackground, drawShadow, drawHighlight, setHighlightThickness, paintComponent
 o printAll
 public void printAll(Graphics gc)
Disables double-buffering, and calls Container.printAll

Overrides:
printAll in class Component
See Also:
setDoubleBuffer
 o enable11Events
 protected void enable11Events(long mask)
For JDK1.1, calls Component.enableEvents (which is final).

 o addNotify
 public void addNotify()
Creates the peer of the canvas.

Overrides:
addNotify in class Canvas
 o getAppletContext
 public AppletContext getAppletContext()
Gets the component's applet's context. The applet context lets an applet control the applet's environment which is usually the browser or the applet viewer.

Returns:
null if the component is not in an applet or the applet is not in a browser
See Also:
getAppletContext
 o minimumSize
 public Dimension minimumSize()
Returns preferredSize().

Overrides:
minimumSize in class Component
 o preferredWidth
 protected int preferredWidth()
Gets the subclass' preferred width (default: 100). The subclass should not include the shadow, highlight, or inset sizes in its calculation; these will be added by JCComponent.

 o preferredHeight
 protected int preferredHeight()
Gets the subclass' preferred height (default: 100). The subclass should not include the shadow, highlight, or inset sizes in its calculation; these will be added by JCComponent.

 o setPreferredSize
 public void setPreferredSize(int w,
                              int h)
Sets the component's preferred size. If either dimension is set to BWTEnum.NOVALUE, it is calculated by the subclass (default size: 100x100).

See Also:
preferredSize
 o preferredSize
 public Dimension preferredSize()
Returns the preferred size of this component. If the app has set the preferred size, that is returned. Otherwise the subclass' preferredWidth and/or preferredHeight method is called. This value may be set from an HTML file using a PARAM tag with a "preferredWidth" name and an int value, and/or a "preferredHeight" name and an int value.

Overrides:
preferredSize in class Component
See Also:
setPreferredSize, preferredWidth, preferredHeight, toInt
 o getDoubleBuffer
 public boolean getDoubleBuffer()
Gets the component's DoubleBuffer value.

See Also:
setDoubleBuffer
 o setDoubleBuffer
 public void setDoubleBuffer(boolean v)
Controls whether double-buffering is used when displaying and updating the component (default: true).

HTML param name/value: "DoubleBuffer"/boolean

See Also:
toBoolean
 o hasFocus
 public boolean hasFocus()
Returns true if this component has keyboard focus.

 o lostFocus
 public boolean lostFocus(Event ev,
                          Object what)
Called when the component loses keyboard focus.

Overrides:
lostFocus in class Component
See Also:
drawHighlight
 o gotFocus
 public boolean gotFocus(Event ev,
                         Object what)
Called when the component receives keyboard focus.

Overrides:
gotFocus in class Component
See Also:
drawHighlight
 o processFocusEvent
 protected void processFocusEvent(FocusEvent focus_ev)
Processes focus events occurring on this component by dispatching them to any registered FocusListener objects.

Overrides:
processFocusEvent in class Component
 o processKeyEvent
 protected void processKeyEvent(KeyEvent key_ev)
Processes key events occurring on this component by dispatching them to any registered KeyListener objects.

Overrides:
processKeyEvent in class Component
 o processMouseEvent
 protected void processMouseEvent(MouseEvent mouse_ev)
Processes mouse events occurring on this component by dispatching them to any registered MouseListener objects.

Overrides:
processMouseEvent in class Component
 o processMouseMotionEvent
 protected void processMouseMotionEvent(MouseEvent mouse_ev)
Processes mouse motion events occurring on this component by dispatching them to any registered MouseMotionListener objects.

Overrides:
processMouseMotionEvent in class Component
 o mouseDown
 public boolean mouseDown(Event ev,
                          int x,
                          int y)
If btn1 is pressed and the component is traversable, requestFocus is called.

Overrides:
mouseDown in class Component
See Also:
isTraversable
 o requestFocus
 public void requestFocus()
Requests the input focus. gotFocus() will be called if this method is successful.

Overrides:
requestFocus in class Component
See Also:
gotFocus
 o reshape
 public synchronized void reshape(int x,
                                  int y,
                                  int width,
                                  int height)
Reshapes the Component to the specified bounding box.

Overrides:
reshape in class Component
 o validate
 public void validate()
Validates a component.

Overrides:
validate in class Component
 o createImage
 public Image createImage(int w,
                          int h)
Creates an off-screen drawable Image to be used for double buffering.

Overrides:
createImage in class Component

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