public class

DefaultCaret

extends Rectangle
implements FocusListener MouseListener MouseMotionListener Caret

java.lang.Object
↳	java.awt.geom.RectangularShape
	↳	java.awt.geom.Rectangle2D
		↳	java.awt.Rectangle
			↳	javax.swing.text.DefaultCaret

Known Direct Subclasses

BasicTextUI.BasicCaret, MotifTextUI.MotifCaret

Class Overview

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 JavaBeans^TM has been added to the java.beans package. Please see XMLEncoder.

Summary

Constants
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.
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.
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.

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Inherited Constants

From class java.awt.geom.Rectangle2D

Fields
protected ChangeEvent	changeEvent	The change event for the model.
protected EventListenerList	listenerList	The event listener list.

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Inherited Fields

From class java.awt.Rectangle

Public Constructors
	DefaultCaret() Constructs a default caret.

Public Methods
void	addChangeListener(ChangeListener l) Adds a listener to track whenever the caret position has been changed.
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.
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.
int	getDot() Fetches the current position of the caret.
Position.Bias	getDotBias() Returns the bias of the caret position.
<T extends EventListener> T[]	getListeners(Class<T> listenerType) Returns an array of all the objects currently registered as `FooListener`s upon this caret.
Point	getMagicCaretPosition() Gets the saved caret position.
int	getMark() Fetches the current position of the mark.
Position.Bias	getMarkBias() Returns the bias of the mark.
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.
void	moveDot(int dot) Moves the caret position to the specified position, with a forward bias.
void	moveDot(int dot, Position.Bias dotBias) Moves the caret position to the specified position, with the specified bias.
void	paint(Graphics g) Renders the caret as a vertical line.
void	removeChangeListener(ChangeListener l) Removes a listener that was tracking caret position changes.
void	setBlinkRate(int rate) Sets the caret blink rate.
void	setDot(int dot) Sets the caret position and mark to the specified position, with a forward bias.
void	setDot(int dot, Position.Bias dotBias) Sets the caret position and mark to the specified position, with the specified bias.
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.
void	setVisible(boolean e) Sets the caret visibility, and repaints the caret.
String	toString() Returns a `String` representing this `Rectangle` and its values.

Protected Methods
void	adjustVisibility(Rectangle nloc) Scrolls the associated view (if necessary) to make the caret visible.
synchronized void	damage(Rectangle r) Damages the area surrounding the caret to cause it to be repainted in a new location.
void	fireStateChanged() Notifies all listeners that have registered interest for notification on this event type.
final JTextComponent	getComponent() Gets the text editor component that this caret is is bound to.
Highlighter.HighlightPainter	getSelectionPainter() Gets the painter for the Highlighter.
void	moveCaret(MouseEvent e) Tries to move the position of the caret from the coordinates of a mouse event, using viewToModel().
void	positionCaret(MouseEvent e) Tries to set the position of the caret from the coordinates of a mouse event, using viewToModel().
synchronized final void	repaint() Cause the caret to be painted.

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Inherited Methods

From class java.awt.Rectangle

void	add(int newx, int newy) Adds a point, specified by the integer arguments `newx,newy` to the bounds of this `Rectangle`.
void	add(Point pt) Adds the specified `Point` to the bounds of this `Rectangle`.
void	add(Rectangle r) Adds a `Rectangle` to this `Rectangle`.
boolean	contains(Point p) Checks whether or not this `Rectangle` contains the specified `Point`.
boolean	contains(int x, int y) Checks whether or not this `Rectangle` contains the point at the specified location `(x,y)`.
boolean	contains(Rectangle r) Checks whether or not this `Rectangle` entirely contains the specified `Rectangle`.
boolean	contains(int X, int Y, int W, int H) Checks whether this `Rectangle` entirely contains the `Rectangle` at the specified location `(X,Y)` with the specified dimensions `(W,H)`.
Rectangle2D	createIntersection(Rectangle2D r) Returns a new `Rectangle2D` object representing the intersection of this `Rectangle2D` with the specified `Rectangle2D`.
Rectangle2D	createUnion(Rectangle2D r) Returns a new `Rectangle2D` object representing the union of this `Rectangle2D` with the specified `Rectangle2D`.
boolean	equals(Object obj) Checks whether two rectangles are equal.
Rectangle	getBounds() Gets the bounding `Rectangle` of this `Rectangle`.
Rectangle2D	getBounds2D()
double	getHeight() Returns the height of the bounding `Rectangle` in `double` precision.
Point	getLocation() Returns the location of this `Rectangle`.
Dimension	getSize() Gets the size of this `Rectangle`, represented by the returned `Dimension`.
double	getWidth() Returns the width of the bounding `Rectangle` in `double` precision.
double	getX() Returns the X coordinate of the bounding `Rectangle` in `double` precision.
double	getY() Returns the Y coordinate of the bounding `Rectangle` in `double` precision.
void	grow(int h, int v) Resizes the `Rectangle` both horizontally and vertically.
boolean	inside(int X, int Y) This method is deprecated. As of JDK version 1.1, replaced by `contains(int, int)`.
Rectangle	intersection(Rectangle r) Computes the intersection of this `Rectangle` with the specified `Rectangle`.
boolean	intersects(Rectangle r) Determines whether or not this `Rectangle` and the specified `Rectangle` intersect.
boolean	isEmpty() Determines whether the `RectangularShape` is empty.
void	move(int x, int y) This method is deprecated. As of JDK version 1.1, replaced by `setLocation(int, int)`.
int	outcode(double x, double y) Determines where the specified coordinates lie with respect to this `Rectangle2D`.
void	reshape(int x, int y, int width, int height) This method is deprecated. As of JDK version 1.1, replaced by `setBounds(int, int, int, int)`.
void	resize(int width, int height) This method is deprecated. As of JDK version 1.1, replaced by `setSize(int, int)`.
void	setBounds(Rectangle r) Sets the bounding `Rectangle` of this `Rectangle` to match the specified `Rectangle`.
void	setBounds(int x, int y, int width, int height) Sets the bounding `Rectangle` of this `Rectangle` to the specified `x`, `y`, `width`, and `height`.
void	setLocation(Point p) Moves this `Rectangle` to the specified location.
void	setLocation(int x, int y) Moves this `Rectangle` to the specified location.
void	setRect(double x, double y, double width, double height) Sets the bounds of this `Rectangle` to the integer bounds which encompass the specified `x`, `y`, `width`, and `height`.
void	setSize(Dimension d) Sets the size of this `Rectangle` to match the specified `Dimension`.
void	setSize(int width, int height) Sets the size of this `Rectangle` to the specified width and height.
String	toString() Returns a `String` representing this `Rectangle` and its values.
void	translate(int dx, int dy) Translates this `Rectangle` the indicated distance, to the right along the X coordinate axis, and downward along the Y coordinate axis.
Rectangle	union(Rectangle r) Computes the union of this `Rectangle` with the specified `Rectangle`.

From class java.awt.geom.Rectangle2D

void	add(double newx, double newy) Adds a point, specified by the double precision arguments `newx` and `newy`, to this `Rectangle2D`.
void	add(Point2D pt) Adds the `Point2D` object `pt` to this `Rectangle2D`.
void	add(Rectangle2D r) Adds a `Rectangle2D` object to this `Rectangle2D`.
boolean	contains(double x, double y)
boolean	contains(double x, double y, double w, double h)
abstract Rectangle2D	createIntersection(Rectangle2D r) Returns a new `Rectangle2D` object representing the intersection of this `Rectangle2D` with the specified `Rectangle2D`.
abstract Rectangle2D	createUnion(Rectangle2D r) Returns a new `Rectangle2D` object representing the union of this `Rectangle2D` with the specified `Rectangle2D`.
boolean	equals(Object obj) Determines whether or not the specified `Object` is equal to this `Rectangle2D`.
Rectangle2D	getBounds2D()
PathIterator	getPathIterator(AffineTransform at) Returns an iteration object that defines the boundary of this `Rectangle2D`.
PathIterator	getPathIterator(AffineTransform at, double flatness) Returns an iteration object that defines the boundary of the flattened `Rectangle2D`.
int	hashCode() Returns the hashcode for this `Rectangle2D`.
static void	intersect(Rectangle2D src1, Rectangle2D src2, Rectangle2D dest) Intersects the pair of specified source `Rectangle2D` objects and puts the result into the specified destination `Rectangle2D` object.
boolean	intersects(double x, double y, double w, double h)
boolean	intersectsLine(Line2D l) Tests if the specified line segment intersects the interior of this `Rectangle2D`.
boolean	intersectsLine(double x1, double y1, double x2, double y2) Tests if the specified line segment intersects the interior of this `Rectangle2D`.
int	outcode(Point2D p) Determines where the specified `Point2D` lies with respect to this `Rectangle2D`.
abstract int	outcode(double x, double y) Determines where the specified coordinates lie with respect to this `Rectangle2D`.
void	setFrame(double x, double y, double w, double h) Sets the location and size of the outer bounds of this `Rectangle2D` to the specified rectangular values.
abstract void	setRect(double x, double y, double w, double h) Sets the location and size of this `Rectangle2D` to the specified `double` values.
void	setRect(Rectangle2D r) Sets this `Rectangle2D` to be the same as the specified `Rectangle2D`.
static void	union(Rectangle2D src1, Rectangle2D src2, Rectangle2D dest) Unions the pair of source `Rectangle2D` objects and puts the result into the specified destination `Rectangle2D` object.

From class java.awt.geom.RectangularShape

Object	clone() Creates a new object of the same class and with the same contents as this object.
boolean	contains(Point2D p) Tests if a specified `Point2D` is inside the boundary of the `Shape`.
boolean	contains(Rectangle2D r) Tests if the interior of the `Shape` entirely contains the specified `Rectangle2D`.
Rectangle	getBounds() Returns an integer `Rectangle` that completely encloses the `Shape`.
double	getCenterX() Returns the X coordinate of the center of the framing rectangle of the `Shape` in `double` precision.
double	getCenterY() Returns the Y coordinate of the center of the framing rectangle of the `Shape` in `double` precision.
Rectangle2D	getFrame() Returns the framing `Rectangle2D` that defines the overall shape of this object.
abstract double	getHeight() Returns the height of the framing rectangle in `double` precision.
double	getMaxX() Returns the largest X coordinate of the framing rectangle of the `Shape` in `double` precision.
double	getMaxY() Returns the largest Y coordinate of the framing rectangle of the `Shape` in `double` precision.
double	getMinX() Returns the smallest X coordinate of the framing rectangle of the `Shape` in `double` precision.
double	getMinY() Returns the smallest Y coordinate of the framing rectangle of the `Shape` in `double` precision.
PathIterator	getPathIterator(AffineTransform at, double flatness) Returns an iterator object that iterates along the `Shape` object's boundary and provides access to a flattened view of the outline of the `Shape` object's geometry.
abstract double	getWidth() Returns the width of the framing rectangle in `double` precision.
abstract double	getX() Returns the X coordinate of the upper-left corner of the framing rectangle in `double` precision.
abstract double	getY() Returns the Y coordinate of the upper-left corner of the framing rectangle in `double` precision.
boolean	intersects(Rectangle2D r) Tests if the interior of the `Shape` intersects the interior of a specified `Rectangle2D`.
abstract boolean	isEmpty() Determines whether the `RectangularShape` is empty.
void	setFrame(Point2D loc, Dimension2D size) Sets the location and size of the framing rectangle of this `Shape` to the specified `Point2D` and `Dimension2D`, respectively.
void	setFrame(Rectangle2D r) Sets the framing rectangle of this `Shape` to be the specified `Rectangle2D`.
abstract void	setFrame(double x, double y, double w, double h) Sets the location and size of the framing rectangle of this `Shape` to the specified rectangular values.
void	setFrameFromCenter(double centerX, double centerY, double cornerX, double cornerY) Sets the framing rectangle of this `Shape` based on the specified center point coordinates and corner point coordinates.
void	setFrameFromCenter(Point2D center, Point2D corner) Sets the framing rectangle of this `Shape` based on a specified center `Point2D` and corner `Point2D`.
void	setFrameFromDiagonal(double x1, double y1, double x2, double y2) Sets the diagonal of the framing rectangle of this `Shape` based on the two specified coordinates.
void	setFrameFromDiagonal(Point2D p1, Point2D p2) Sets the diagonal of the framing rectangle of this `Shape` based on two specified `Point2D` objects.

From class java.lang.Object

Object	clone() Creates and returns a copy of this object.
boolean	equals(Object obj) Indicates whether some other object is "equal to" this one.
void	finalize() Called by the garbage collector on an object when garbage collection determines that there are no more references to the object.
final Class<?>	getClass() Returns the runtime class of this `Object`.
int	hashCode() Returns a hash code value for the object.
final void	notify() Wakes up a single thread that is waiting on this object's monitor.
final void	notifyAll() Wakes up all threads that are waiting on this object's monitor.
String	toString() Returns a string representation of the object.
final void	wait() Causes the current thread to wait until another thread invokes the `notify()` method or the `notifyAll()` method for this object.
final void	wait(long timeout, int nanos) Causes the current thread to wait until another thread invokes the `notify()` method or the `notifyAll()` method for this object, or some other thread interrupts the current thread, or a certain amount of real time has elapsed.
final void	wait(long timeout) Causes the current thread to wait until either another thread invokes the `notify()` method or the `notifyAll()` method for this object, or a specified amount of time has elapsed.

From interface java.awt.Shape

abstract boolean	contains(double x, double y) Tests if the specified coordinates are inside the boundary of the `Shape`.
abstract boolean	contains(Point2D p) Tests if a specified `Point2D` is inside the boundary of the `Shape`.
abstract boolean	contains(double x, double y, double w, double h) Tests if the interior of the `Shape` entirely contains the specified rectangular area.
abstract boolean	contains(Rectangle2D r) Tests if the interior of the `Shape` entirely contains the specified `Rectangle2D`.
abstract Rectangle	getBounds() Returns an integer `Rectangle` that completely encloses the `Shape`.
abstract Rectangle2D	getBounds2D() Returns a high precision and more accurate bounding box of the `Shape` than the `getBounds` method.
abstract PathIterator	getPathIterator(AffineTransform at) Returns an iterator object that iterates along the `Shape` boundary and provides access to the geometry of the `Shape` outline.
abstract PathIterator	getPathIterator(AffineTransform at, double flatness) Returns an iterator object that iterates along the `Shape` boundary and provides access to a flattened view of the `Shape` outline geometry.
abstract boolean	intersects(double x, double y, double w, double h) Tests if the interior of the `Shape` intersects the interior of a specified rectangular area.
abstract boolean	intersects(Rectangle2D r) Tests if the interior of the `Shape` intersects the interior of a specified `Rectangle2D`.

From interface java.awt.event.FocusListener

From interface java.awt.event.MouseListener

From interface java.awt.event.MouseMotionListener

From interface javax.swing.text.Caret

abstract void	addChangeListener(ChangeListener l) Adds a listener to track whenever the caret position has been changed.
abstract void	deinstall(JTextComponent c) Called when the UI is being removed from the interface of a JTextComponent.
abstract int	getBlinkRate() Gets the blink rate of the caret.
abstract int	getDot() Fetches the current position of the caret.
abstract Point	getMagicCaretPosition() Gets the current caret visual location.
abstract int	getMark() Fetches the current position of the mark.
abstract void	install(JTextComponent c) Called when the UI is being installed into the interface of a JTextComponent.
abstract boolean	isSelectionVisible() Determines if the selection is currently visible.
abstract boolean	isVisible() Determines if the caret is currently visible.
abstract void	moveDot(int dot) Moves the caret position (dot) to some other position, leaving behind the mark.
abstract void	paint(Graphics g) Renders the caret.
abstract void	removeChangeListener(ChangeListener l) Removes a listener that was tracking caret position changes.
abstract void	setBlinkRate(int rate) Sets the blink rate of the caret.
abstract void	setDot(int dot) Sets the caret position to some position.
abstract void	setMagicCaretPosition(Point p) Set the current caret visual location.
abstract void	setSelectionVisible(boolean v) Sets the visibility of the selection
abstract void	setVisible(boolean v) Sets the visibility of the caret.

Constants

public static final 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.

public static final 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. In that case the caret position is adjusted to the end of the document.

public static final 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

protected ChangeEvent changeEvent

The change event for the model. Only one ChangeEvent is needed per model instance since the event's only (read-only) state is the source property. The source of events generated here is always "this".

protected EventListenerList listenerList

The event listener list.

Public Constructors

public DefaultCaret ()

Constructs a default caret.

Public Methods

public void addChangeListener (ChangeListener l)

Adds a listener to track whenever the caret position has been changed.

Parameters

l	the listener

public void deinstall (JTextComponent c)

Called when the UI is being removed from the interface of a JTextComponent. This is used to unregister any listeners that were attached.

Parameters

c	the component

public boolean equals (Object obj)

Compares this object to the specified object. The superclass behavior of comparing rectangles is not desired, so this is changed to the Object behavior.

Parameters

obj	the object to compare this font with

Returns

true if the objects are equal; false otherwise

public void focusGained (FocusEvent e)

Called when the component containing the caret gains focus. This is implemented to set the caret to visible if the component is editable.

Parameters

e	the focus event

public void focusLost (FocusEvent e)

Called when the component containing the caret loses focus. This is implemented to set the caret to visibility to false.

Parameters

e	the focus event

public int getBlinkRate ()

Gets the caret blink rate.

Returns

the delay in milliseconds. If this is zero the caret will not blink.

public ChangeListener[] getChangeListeners ()

Returns an array of all the change listeners registered on this caret.

Returns

all of this caret's ChangeListeners or an empty array if no change listeners are currently registered

public int getDot ()

Fetches the current position of the caret.

Returns

the position >= 0

public Position.Bias getDotBias ()

Returns the bias of the caret position.

Returns

the bias of the caret position

public T[] getListeners (Class<T> listenerType)

Returns an array of all the objects currently registered as 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.

Parameters

listenerType	the type of listeners requested; this parameter should specify an interface that descends from `java.util.EventListener`

Returns

an array of all objects registered as FooListeners on this component, or an empty array if no such listeners have been added

Throws

ClassCastException	if `listenerType` doesn't specify a class or interface that implements `java.util.EventListener`

public Point getMagicCaretPosition ()

Gets the saved caret position.

Returns

the position see #setMagicCaretPosition

public int getMark ()

Fetches the current position of the mark. If there is a selection, the dot and mark will not be the same.

Returns

the position >= 0

public Position.Bias getMarkBias ()

Returns the bias of the mark.

Returns

the bias of the mark

public int getUpdatePolicy ()

Gets the caret movement policy on document updates.

Returns

one of the following values : UPDATE_WHEN_ON_EDT, NEVER_UPDATE, ALWAYS_UPDATE

public void install (JTextComponent c)

Called when the UI is being installed into the interface of a JTextComponent. This can be used to gain access to the model that is being navigated by the implementation of this interface. Sets the dot and mark to 0, and establishes document, property change, focus, mouse, and mouse motion listeners.

Parameters

c	the component

public boolean isActive ()

Determines if the caret is currently active.

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.

Returns

true if active else false

public boolean isSelectionVisible ()

Checks whether the current selection is visible.

Returns

true if the selection is visible

public boolean isVisible ()

Indicates whether or not the caret is currently visible. As the caret flashes on and off the return value of this will change between true, when the caret is painted, and false, when the caret is not painted. 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.

Returns

true if visible else false

public void mouseClicked (MouseEvent e)

Called when the mouse is clicked. If the click was generated from button1, a double click selects a word, and a triple click the current line.

Parameters

e	the mouse event

public void mouseDragged (MouseEvent e)

Moves the caret position according to the mouse pointer's current location. This effectively extends the selection. By default, this is only done for mouse button 1.

Parameters

e	the mouse event

public void mouseEntered (MouseEvent e)

Called when the mouse enters a region.

Parameters

e	the mouse event

public void mouseExited (MouseEvent e)

Called when the mouse exits a region.

Parameters

e	the mouse event

public void mouseMoved (MouseEvent e)

Called when the mouse is moved.

Parameters

e	the mouse event

public 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. If the shift key is held down, the caret will be moved, potentially resulting in a selection, otherwise the caret position will be set to the new location. If the component is not enabled, there will be no request for focus.

Parameters

e	the mouse event

public void mouseReleased (MouseEvent e)

Called when the mouse is released.

Parameters

e	the mouse event

public void moveDot (int dot)

Moves the caret position to the specified position, with a forward bias.

Parameters

dot	the position >= 0

public void moveDot (int dot, Position.Bias dotBias)

Moves the caret position to the specified position, with the specified bias.

Parameters

dot	the position >= 0
dotBias	the bias for this position, not `null`

Throws

IllegalArgumentException	if the bias is `null`

public void paint (Graphics g)

Renders the caret as a vertical line. If this is reimplemented the damage method should also be reimplemented as it assumes the shape of the caret is a vertical line. Sets the caret color to the value returned by getCaretColor().

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).

Parameters

g	the graphics context

public void removeChangeListener (ChangeListener l)

Removes a listener that was tracking caret position changes.

Parameters

l	the listener

public void setBlinkRate (int rate)

Sets the caret blink rate.

Parameters

rate	the rate in milliseconds, 0 to stop blinking

public void setDot (int dot)

Sets the caret position and mark to the specified position, with a forward bias. This implicitly sets the selection range to zero.

Parameters

dot	the position >= 0

public void setDot (int dot, Position.Bias dotBias)

Sets the caret position and mark to the specified position, with the specified bias. This implicitly sets the selection range to zero.

Parameters

dot	the position >= 0
dotBias	the bias for this position, not `null`

Throws

IllegalArgumentException	if the bias is `null`

public void setMagicCaretPosition (Point p)

Saves the current caret position. This is used when caret up/down actions occur, moving between lines that have uneven end positions.

Parameters

p	the position

public void setSelectionVisible (boolean vis)

Changes the selection visibility.

Parameters

vis	the new visibility

public void setUpdatePolicy (int policy)

Sets the caret movement policy on the document updates. Normally the caret updates its absolute position within the document on insertions occurred before or at the caret position and on removals before the caret position. 'Absolute position' means here the position relative to the start of the document. For example if a character is typed within editable text component it is inserted at the caret position and the caret moves to the next absolute position within the document due to insertion and if 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.

Parameters

policy	one of the following values : `UPDATE_WHEN_ON_EDT`, `NEVER_UPDATE`, `ALWAYS_UPDATE`

Throws

IllegalArgumentException	if invalid value is passed

public void setVisible (boolean e)

Sets the caret visibility, and repaints the caret. It is important to understand the relationship between this method, 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):

isActive(): true
isVisible(): true or false depending on whether or not the caret is blinked on or off

setVisible(false):

isActive(): false
isVisible(): false

Parameters

e	the visibility specifier

public String toString ()

Returns a String representing this Rectangle and its values.

Returns

a String representing this Rectangle object's coordinate and size values.

Protected Methods

protected void adjustVisibility (Rectangle nloc)

Scrolls the associated view (if necessary) to make the caret visible. Since how this should be done is somewhat of a policy, this method can be reimplemented to change the behavior. By default the scrollRectToVisible method is called on the associated component.

Parameters

nloc	the new position to scroll to

protected synchronized void damage (Rectangle r)

Damages the area surrounding the caret to cause it to be repainted in a new location. If paint() is reimplemented, this method should also be reimplemented. This method should update the caret bounds (x, y, width, and height).

Parameters

r	the current location of the caret

protected void fireStateChanged ()

Notifies all listeners that have registered interest for notification on this event type. The event instance is lazily created using the parameters passed into the fire method. The listener list is processed last to first.

protected final JTextComponent getComponent ()

Gets the text editor component that this caret is is bound to.

Returns

the component

protected Highlighter.HighlightPainter getSelectionPainter ()

Gets the painter for the Highlighter.

Returns

the painter

protected void moveCaret (MouseEvent e)

Tries to move the position of the caret from the coordinates of a mouse event, using viewToModel(). This will cause a selection if the dot and mark are different.

Parameters

e	the mouse event

protected void positionCaret (MouseEvent e)

Tries to set the position of the caret from the coordinates of a mouse event, using viewToModel().

Parameters

e	the mouse event

protected final synchronized void repaint ()

Cause the caret to be painted. The repaint area is the bounding box of the caret (i.e. the caret rectangle or this).

This method is thread safe, although most Swing methods are not. Please see How to Use Threads for more information.

Interfaces

Classes

Exceptions

DefaultCaret

Class Overview

See Also

Summary

Constants

public static final int ALWAYS_UPDATE

See Also

public static final int NEVER_UPDATE

See Also

public static final int UPDATE_WHEN_ON_EDT

See Also

Fields

protected ChangeEvent changeEvent

protected EventListenerList listenerList

Public Constructors

public DefaultCaret ()

Public Methods

public void addChangeListener (ChangeListener l)

Parameters

See Also

public void deinstall (JTextComponent c)

Parameters

See Also

public boolean equals (Object obj)

Parameters

Returns

public void focusGained (FocusEvent e)

Parameters

See Also

public void focusLost (FocusEvent e)

Parameters

See Also

public int getBlinkRate ()

Returns

See Also

public ChangeListener[] getChangeListeners ()

Returns

See Also

public int getDot ()

Returns

See Also

public Position.Bias getDotBias ()

Returns

public T[] getListeners (Class<T> listenerType)

Parameters

Returns

Throws

See Also

public Point getMagicCaretPosition ()

Returns

public int getMark ()

Returns

See Also

public Position.Bias getMarkBias ()

Returns

public int getUpdatePolicy ()

Returns

See Also

public void install (JTextComponent c)

Parameters

See Also

public boolean isActive ()

Returns

See Also

public boolean isSelectionVisible ()

Returns

public boolean isVisible ()

Returns

See Also

public void mouseClicked (MouseEvent e)

Parameters

See Also

public void mouseDragged (MouseEvent e)

Parameters

See Also

public void mouseEntered (MouseEvent e)

Parameters