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JavaTM 2 Platform Standard Ed. 5.0 |
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java.lang.Objectjava.awt.geom.RectangularShape
java.awt.geom.Rectangle2D
java.awt.Rectangle
javax.swing.text.DefaultCaret
public class DefaultCaret
A default implementation of Caret. The caret is rendered as a vertical line in the color specified by the CaretColor property of the associated JTextComponent. It can blink at the rate specified by the BlinkRate property.
This implementation expects two sources of asynchronous notification.
The timer thread fires asynchronously, and causes the caret to simply
repaint the most recent bounding box. The caret also tracks change
as the document is modified. Typically this will happen on the
event dispatch thread as a result of some mouse or keyboard event.
The caret behavior on both synchronous and asynchronous documents updates
is controlled by UpdatePolicy property. The repaint of the
new caret location will occur on the event thread in any case, as calls to
modelToView are only safe on the event thread.
The caret acts as a mouse and focus listener on the text component it has been installed in, and defines the caret semantics based upon those events. The listener methods can be reimplemented to change the semantics. By default, the first mouse button will be used to set focus and caret position. Dragging the mouse pointer with the first mouse button will sweep out a selection that is contiguous in the model. If the associated text component is editable, the caret will become visible when focus is gained, and invisible when focus is lost.
The Highlighter bound to the associated text component is used to
render the selection by default.
Selection appearance can be customized by supplying a
painter to use for the highlights. By default a painter is used that
will render a solid color as specified in the associated text component
in the SelectionColor property. This can easily be changed
by reimplementing the
getSelectionHighlighter
method.
A customized caret appearance can be achieved by reimplementing the paint method. If the paint method is changed, the damage method should also be reimplemented to cause a repaint for the area needed to render the caret. The caret extends the Rectangle class which is used to hold the bounding box for where the caret was last rendered. This enables the caret to repaint in a thread-safe manner when the caret moves without making a call to modelToView which is unstable between model updates and view repair (i.e. the order of delivery to DocumentListeners is not guaranteed).
The magic caret position is set to null when the caret position changes. A timer is used to determine the new location (after the caret change). When the timer fires, if the magic caret position is still null it is reset to the current caret position. Any actions that change the caret position and want the magic caret position to remain the same, must remember the magic caret position, change the cursor, and then set the magic caret position to its original value. This has the benefit that only actions that want the magic caret position to persist (such as open/down) need to know about it.
Warning:
Serialized objects of this class will not be compatible with
future Swing releases. The current serialization support is
appropriate for short term storage or RMI between applications running
the same version of Swing. As of 1.4, support for long term storage
of all JavaBeansTM
has been added to the java.beans package.
Please see XMLEncoder.
Caret| Nested Class Summary |
|---|
| Nested classes/interfaces inherited from class java.awt.geom.Rectangle2D |
|---|
Rectangle2D.Double, Rectangle2D.Float |
| Field Summary | |
|---|---|
static int |
ALWAYS_UPDATE
Indicates that the caret position is to be always updated accordingly to the document changes regardless whether the document updates are performed on the Event Dispatching Thread or not. |
protected ChangeEvent |
changeEvent
The change event for the model. |
protected EventListenerList |
listenerList
The event listener list. |
static int |
NEVER_UPDATE
Indicates that the caret should remain at the same absolute position in the document regardless of any document updates, except when the document length becomes less than the current caret position due to removal. |
static int |
UPDATE_WHEN_ON_EDT
Indicates that the caret position is to be updated only when document changes are performed on the Event Dispatching Thread. |
| Fields inherited from class java.awt.Rectangle |
|---|
height, width, x, y |
| Fields inherited from class java.awt.geom.Rectangle2D |
|---|
OUT_BOTTOM, OUT_LEFT, OUT_RIGHT, OUT_TOP |
| Constructor Summary | |
|---|---|
DefaultCaret()
Constructs a default caret. |
|
| Method Summary | ||
|---|---|---|
void |
addChangeListener(ChangeListener l)
Adds a listener to track whenever the caret position has been changed. |
|
protected void |
adjustVisibility(Rectangle nloc)
Scrolls the associated view (if necessary) to make the caret visible. |
|
protected void |
damage(Rectangle r)
Damages the area surrounding the caret to cause it to be repainted in a new location. |
|
void |
deinstall(JTextComponent c)
Called when the UI is being removed from the interface of a JTextComponent. |
|
boolean |
equals(Object obj)
Compares this object to the specified object. |
|
protected void |
fireStateChanged()
Notifies all listeners that have registered interest for notification on this event type. |
|
void |
focusGained(FocusEvent e)
Called when the component containing the caret gains focus. |
|
void |
focusLost(FocusEvent e)
Called when the component containing the caret loses focus. |
|
int |
getBlinkRate()
Gets the caret blink rate. |
|
ChangeListener[] |
getChangeListeners()
Returns an array of all the change listeners registered on this caret. |
|
protected JTextComponent |
getComponent()
Gets the text editor component that this caret is is bound to. |
|
int |
getDot()
Fetches the current position of the caret. |
|
|
getListeners(Class<T> listenerType)
Returns an array of all the objects currently registered as FooListeners
upon this caret. |
|
Point |
getMagicCaretPosition()
Gets the saved caret position. |
|
int |
getMark()
Fetches the current position of the mark. |
|
protected Highlighter.HighlightPainter |
getSelectionPainter()
Gets the painter for the Highlighter. |
|
int |
getUpdatePolicy()
Gets the caret movement policy on document updates. |
|
void |
install(JTextComponent c)
Called when the UI is being installed into the interface of a JTextComponent. |
|
boolean |
isActive()
Determines if the caret is currently active. |
|
boolean |
isSelectionVisible()
Checks whether the current selection is visible. |
|
boolean |
isVisible()
Indicates whether or not the caret is currently visible. |
|
void |
mouseClicked(MouseEvent e)
Called when the mouse is clicked. |
|
void |
mouseDragged(MouseEvent e)
Moves the caret position according to the mouse pointer's current location. |
|
void |
mouseEntered(MouseEvent e)
Called when the mouse enters a region. |
|
void |
mouseExited(MouseEvent e)
Called when the mouse exits a region. |
|
void |
mouseMoved(MouseEvent e)
Called when the mouse is moved. |
|
void |
mousePressed(MouseEvent e)
If button 1 is pressed, this is implemented to request focus on the associated text component, and to set the caret position. |
|
void |
mouseReleased(MouseEvent e)
Called when the mouse is released. |
|
protected void |
moveCaret(MouseEvent e)
Tries to move the position of the caret from the coordinates of a mouse event, using viewToModel(). |
|
void |
moveDot(int dot)
Moves the caret position to some other position. |
|
void |
paint(Graphics g)
Renders the caret as a vertical line. |
|
protected void |
positionCaret(MouseEvent e)
Tries to set the position of the caret from the coordinates of a mouse event, using viewToModel(). |
|
void |
removeChangeListener(ChangeListener l)
Removes a listener that was tracking caret position changes. |
|
protected void |
repaint()
Cause the caret to be painted. |
|
void |
setBlinkRate(int rate)
Sets the caret blink rate. |
|
void |
setDot(int dot)
Sets the caret position and mark to some position. |
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void |
setMagicCaretPosition(Point p)
Saves the current caret position. |
|
void |
setSelectionVisible(boolean vis)
Changes the selection visibility. |
|
void |
setUpdatePolicy(int policy)
Sets the caret movement policy on the document updates. |
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void |
setVisible(boolean e)
Sets the caret visibility, and repaints the caret. |
|
String |
toString()
Returns a String representing this
Rectangle and its values. |
|
| Methods inherited from class java.awt.Rectangle |
|---|
add, add, add, contains, contains, contains, contains, createIntersection, createUnion, getBounds, getBounds2D, getHeight, getLocation, getSize, getWidth, getX, getY, grow, inside, intersection, intersects, isEmpty, move, outcode, reshape, resize, setBounds, setBounds, setLocation, setLocation, setRect, setSize, setSize, translate, union |
| Methods inherited from class java.awt.geom.Rectangle2D |
|---|
add, add, add, contains, contains, getPathIterator, getPathIterator, hashCode, intersect, intersects, intersectsLine, intersectsLine, outcode, setFrame, setRect, union |
| Methods inherited from class java.awt.geom.RectangularShape |
|---|
clone, contains, contains, getCenterX, getCenterY, getFrame, getMaxX, getMaxY, getMinX, getMinY, intersects, setFrame, setFrame, setFrameFromCenter, setFrameFromCenter, setFrameFromDiagonal, setFrameFromDiagonal |
| Methods inherited from class java.lang.Object |
|---|
finalize, getClass, notify, notifyAll, wait, wait, wait |
| Methods inherited from interface java.awt.Shape |
|---|
contains, contains, contains, contains, getPathIterator, getPathIterator, intersects, intersects |
| Field Detail |
|---|
public static final int UPDATE_WHEN_ON_EDT
setUpdatePolicy(int),
getUpdatePolicy(),
Constant Field Valuespublic static final int NEVER_UPDATE
setUpdatePolicy(int),
getUpdatePolicy(),
Constant Field Valuespublic static final int ALWAYS_UPDATE
setUpdatePolicy(int),
getUpdatePolicy(),
Constant Field Valuesprotected EventListenerList listenerList
protected transient ChangeEvent changeEvent
| Constructor Detail |
|---|
public DefaultCaret()
| Method Detail |
|---|
public void setUpdatePolicy(int policy)
BACKSPACE is typed then caret decreases its absolute
position due to removal of a character before it. Sometimes
it may be useful to turn off the caret position updates so that
the caret stays at the same absolute position within the
document position regardless of any document updates.
The following update policies are allowed:
NEVER_UPDATE: the caret stays at the same
absolute position in the document regardless of any document
updates, except when document length becomes less than
the current caret position due to removal. In that case caret
position is adjusted to the end of the document.
The caret doesn't try to keep itself visible by scrolling
the associated view when using this policy. ALWAYS_UPDATE: the caret always tracks document
changes. For regular changes it increases its position
if an insertion occurs before or at its current position,
and decreases position if a removal occurs before
its current position. For undo/redo updates it is always
moved to the position where update occurred. The caret
also tries to keep itself visible by calling
adjustVisibility method.UPDATE_WHEN_ON_EDT: acts like ALWAYS_UPDATE
if the document updates are performed on the Event Dispatching Thread
and like NEVER_UPDATE if updates are performed on
other thread.
The default property value is UPDATE_WHEN_ON_EDT.
policy - one of the following values : UPDATE_WHEN_ON_EDT,
NEVER_UPDATE, ALWAYS_UPDATE
IllegalArgumentException - if invalid value is passedgetUpdatePolicy(),
adjustVisibility(java.awt.Rectangle),
UPDATE_WHEN_ON_EDT,
NEVER_UPDATE,
ALWAYS_UPDATEpublic int getUpdatePolicy()
UPDATE_WHEN_ON_EDT,
NEVER_UPDATE, ALWAYS_UPDATEsetUpdatePolicy(int),
UPDATE_WHEN_ON_EDT,
NEVER_UPDATE,
ALWAYS_UPDATEprotected final JTextComponent getComponent()
protected final void repaint()
This method is thread safe, although most Swing methods are not. Please see Threads and Swing for more information.
protected void damage(Rectangle r)
r - the current location of the caretpaint(java.awt.Graphics)protected void adjustVisibility(Rectangle nloc)
nloc - the new position to scroll toprotected Highlighter.HighlightPainter getSelectionPainter()
protected void positionCaret(MouseEvent e)
e - the mouse eventprotected void moveCaret(MouseEvent e)
e - the mouse eventpublic void focusGained(FocusEvent e)
focusGained in interface FocusListenere - the focus eventFocusListener.focusGained(java.awt.event.FocusEvent)public void focusLost(FocusEvent e)
focusLost in interface FocusListenere - the focus eventFocusListener.focusLost(java.awt.event.FocusEvent)public void mouseClicked(MouseEvent e)
mouseClicked in interface MouseListenere - the mouse eventMouseListener.mouseClicked(java.awt.event.MouseEvent)public void mousePressed(MouseEvent e)
mousePressed in interface MouseListenere - the mouse eventMouseListener.mousePressed(java.awt.event.MouseEvent)public void mouseReleased(MouseEvent e)
mouseReleased in interface MouseListenere - the mouse eventMouseListener.mouseReleased(java.awt.event.MouseEvent)public void mouseEntered(MouseEvent e)
mouseEntered in interface MouseListenere - the mouse eventMouseListener.mouseEntered(java.awt.event.MouseEvent)public void mouseExited(MouseEvent e)
mouseExited in interface MouseListenere - the mouse eventMouseListener.mouseExited(java.awt.event.MouseEvent)public void mouseDragged(MouseEvent e)
mouseDragged in interface MouseMotionListenere - the mouse eventMouseMotionListener.mouseDragged(java.awt.event.MouseEvent)public void mouseMoved(MouseEvent e)
mouseMoved in interface MouseMotionListenere - the mouse eventMouseMotionListener.mouseMoved(java.awt.event.MouseEvent)public void paint(Graphics g)
If there are multiple text directions present in the associated document, a flag indicating the caret bias will be rendered. This will occur only if the associated document is a subclass of AbstractDocument and there are multiple bidi levels present in the bidi element structure (i.e. the text has multiple directions associated with it).
paint in interface Caretg - the graphics contextdamage(java.awt.Rectangle)public void install(JTextComponent c)
install in interface Caretc - the componentCaret.install(javax.swing.text.JTextComponent)public void deinstall(JTextComponent c)
deinstall in interface Caretc - the componentCaret.deinstall(javax.swing.text.JTextComponent)public void addChangeListener(ChangeListener l)
addChangeListener in interface Caretl - the listenerCaret.addChangeListener(javax.swing.event.ChangeListener)public void removeChangeListener(ChangeListener l)
removeChangeListener in interface Caretl - the listenerCaret.removeChangeListener(javax.swing.event.ChangeListener)public ChangeListener[] getChangeListeners()
ChangeListeners
or an empty
array if no change listeners are currently registeredaddChangeListener(javax.swing.event.ChangeListener),
removeChangeListener(javax.swing.event.ChangeListener)protected void fireStateChanged()
EventListenerListpublic <T extends EventListener> T[] getListeners(Class<T> listenerType)
FooListeners
upon this caret.
FooListeners are registered using the
addFooListener method.
You can specify the listenerType argument
with a class literal,
such as
FooListener.class.
For example, you can query a
DefaultCaret c
for its change listeners with the following code:
ChangeListener[] cls = (ChangeListener[])(c.getListeners(ChangeListener.class));If no such listeners exist, this method returns an empty array.
listenerType - the type of listeners requested; this parameter
should specify an interface that descends from
java.util.EventListener
FooListeners on this component,
or an empty array if no such
listeners have been added
ClassCastException - if listenerType
doesn't specify a class or interface that implements
java.util.EventListenergetChangeListeners()public void setSelectionVisible(boolean vis)
setSelectionVisible in interface Caretvis - the new visibilitypublic boolean isSelectionVisible()
isSelectionVisible in interface Caretpublic boolean isActive()
This method returns whether or not the Caret
is currently in a blinking state. It does not provide
information as to whether it is currently blinked on or off.
To determine if the caret is currently painted use the
isVisible method.
true if active else falseisVisible()public boolean isVisible()
isActive indicates whether
or not the caret is in a blinking state, such that it can
be visible, and isVisible indicates whether or not
the caret is actually visible.
Subclasses that wish to render a different flashing caret should override paint and only paint the caret if this method returns true.
isVisible in interface CaretCaret.isVisible(),
isActive()public void setVisible(boolean e)
isVisible and isActive.
Calling this method with a value of true activates the
caret blinking. Setting it to false turns it completely off.
To determine whether the blinking is active, you should call
isActive. In effect, isActive is an
appropriate corresponding "getter" method for this one.
isVisible can be used to fetch the current
visibility status of the caret, meaning whether or not it is currently
painted. This status will change as the caret blinks on and off.
Here's a list showing the potential return values of both
isActive and isVisible
after calling this method:
setVisible(true):
setVisible(false):
setVisible in interface Carete - the visibility specifierisActive(),
Caret.setVisible(boolean)public void setBlinkRate(int rate)
setBlinkRate in interface Caretrate - the rate in milliseconds, 0 to stop blinkingCaret.setBlinkRate(int)public int getBlinkRate()
getBlinkRate in interface CaretCaret.getBlinkRate()public int getDot()
getDot in interface CaretCaret.getDot()public int getMark()
getMark in interface CaretCaret.getMark()public void setDot(int dot)
setDot in interface Caretdot - the position >= 0Caret.setDot(int)public void moveDot(int dot)
moveDot in interface Caretdot - the position >= 0Caret.moveDot(int)public void setMagicCaretPosition(Point p)
setMagicCaretPosition in interface Caretp - the positiongetMagicCaretPosition()public Point getMagicCaretPosition()
getMagicCaretPosition in interface CaretCaret.setMagicCaretPosition(java.awt.Point)public boolean equals(Object obj)
equals in class Rectangleobj - the object to compare this font with
true if the objects are equal;
false otherwiseObject.hashCode(),
Hashtablepublic String toString()
RectangleString representing this
Rectangle and its values.
toString in class RectangleString representing this
Rectangle object's coordinate and size values.
|
JavaTM 2 Platform Standard Ed. 5.0 |
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Copyright 2004 Sun Microsystems, Inc. All rights reserved. Use is subject to license terms. Also see the documentation redistribution policy.