public class DefaultCaret extends Rectangleimplements Caret , FocusListener , MouseListener , MouseMotionListener
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 getSelectionPainter 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™ has been added to the java.beans package. Please see XMLEncoder.
Caret
Rectangle2D.Double , Rectangle2D.Float | Modifier and Type | Field and Description |
|---|---|
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.
|
OUT_BOTTOM, OUT_LEFT, OUT_RIGHT, OUT_TOP| Constructor and Description |
|---|
DefaultCaret()
Constructs a default caret.
|
| Modifier and Type | Method and Description |
|---|---|
void |
addChangeListener(ChangeListener
Adds a listener to track whenever the caret position has been changed.
|
protected void |
adjustVisibility(Rectangle
Scrolls the associated view (if necessary) to make the caret visible.
|
protected void |
damage(Rectangle
Damages the area surrounding the caret to cause it to be repainted in a new location.
|
void |
deinstall(JTextComponent
Called when the UI is being removed from the interface of a JTextComponent.
|
boolean |
equals(Object
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
Called when the component containing the caret gains focus.
|
void |
focusLost(FocusEvent
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.
|
Position |
getDotBias()
Returns the bias of the caret position.
|
<T extends EventListener |
getListeners(Class
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.
|
Position |
getMarkBias()
Returns the bias of the mark.
|
protected Highlighter |
getSelectionPainter()
Gets the painter for the Highlighter.
|
int |
getUpdatePolicy()
Gets the caret movement policy on document updates.
|
void |
install(JTextComponent
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
Called when the mouse is clicked.
|
void |
mouseDragged(MouseEvent
Moves the caret position according to the mouse pointer's current location.
|
void |
mouseEntered(MouseEvent
Called when the mouse enters a region.
|
void |
mouseExited(MouseEvent
Called when the mouse exits a region.
|
void |
mouseMoved(MouseEvent
Called when the mouse is moved.
|
void |
mousePressed(MouseEvent
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
Called when the mouse is released.
|
protected void |
moveCaret(MouseEvent
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 the specified position, with a forward bias.
|
void |
moveDot(int dot, Position
Moves the caret position to the specified position, with the specified bias.
|
void |
paint(Graphics
Renders the caret as a vertical line.
|
protected void |
positionCaret(MouseEvent
Tries to set the position of the caret from the coordinates of a mouse event, using viewToModel().
|
void |
removeChangeListener(ChangeListener
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 the specified position, with a forward bias.
|
void |
setDot(int dot, Position
Sets the caret position and mark to the specified position, with the specified bias.
|
void |
setMagicCaretPosition(Point
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.
|
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, unionadd, add, add, contains, contains, getPathIterator, getPathIterator, hashCode, intersect, intersects, intersectsLine, intersectsLine, outcode, setFrame, setRect, unionclone, contains, contains, getCenterX, getCenterY, getFrame, getMaxX, getMaxY, getMinX, getMinY, intersects, setFrame, setFrame, setFrameFromCenter, setFrameFromCenter, setFrameFromDiagonal, setFrameFromDiagonalfinalize, getClass, notify, notifyAll, wait, wait, waitcontains, contains, contains, contains, getPathIterator, getPathIterator, intersects, intersectspublic static final int UPDATE_WHEN_ON_EDT
setUpdatePolicy(int),
getUpdatePolicy(),
Constant Field Values
public static final int NEVER_UPDATE
setUpdatePolicy(int),
getUpdatePolicy(),
Constant Field Values
public static final int ALWAYS_UPDATE
setUpdatePolicy(int),
getUpdatePolicy(),
Constant Field Values
protected EventListenerListlistenerList
protected transient ChangeEventchangeEvent
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 passed
getUpdatePolicy(),
adjustVisibility(java.awt.Rectangle),
UPDATE_WHEN_ON_EDT,
NEVER_UPDATE,
ALWAYS_UPDATE
public int getUpdatePolicy()
UPDATE_WHEN_ON_EDT,
NEVER_UPDATE,
ALWAYS_UPDATE
setUpdatePolicy(int),
UPDATE_WHEN_ON_EDT,
NEVER_UPDATE,
ALWAYS_UPDATE
protected final JTextComponentgetComponent()
protected final void repaint()
This method is thread safe, although most Swing methods are not. Please see Concurrency in Swing for more information.
protected void damage(Rectangler)
r - the current location of the caret
paint(java.awt.Graphics)
protected void adjustVisibility(Rectanglenloc)
nloc - the new position to scroll to
protected Highlighter.HighlightPainter getSelectionPainter()
protected void positionCaret(MouseEvente)
e - the mouse event
protected void moveCaret(MouseEvente)
e - the mouse event
public void focusGained(FocusEvente)
focusGained in interface
FocusListener
e - the focus event
FocusListener.focusGained(java.awt.event.FocusEvent)
public void focusLost(FocusEvente)
focusLost in interface
FocusListener
e - the focus event
FocusListener.focusLost(java.awt.event.FocusEvent)
public void mouseClicked(MouseEvente)
mouseClicked in interface
MouseListener
e - the mouse event
MouseListener.mouseClicked(java.awt.event.MouseEvent)
public void mousePressed(MouseEvente)
mousePressed in interface
MouseListener
e - the mouse event
MouseListener.mousePressed(java.awt.event.MouseEvent)
public void mouseReleased(MouseEvente)
mouseReleased in interface
MouseListener
e - the mouse event
MouseListener.mouseReleased(java.awt.event.MouseEvent)
public void mouseEntered(MouseEvente)
mouseEntered in interface
MouseListener
e - the mouse event
MouseListener.mouseEntered(java.awt.event.MouseEvent)
public void mouseExited(MouseEvente)
mouseExited in interface
MouseListener
e - the mouse event
MouseListener.mouseExited(java.awt.event.MouseEvent)
public void mouseDragged(MouseEvente)
mouseDragged in interface
MouseMotionListener
e - the mouse event
MouseMotionListener.mouseDragged(java.awt.event.MouseEvent)
public void mouseMoved(MouseEvente)
mouseMoved in interface
MouseMotionListener
e - the mouse event
MouseMotionListener.mouseMoved(java.awt.event.MouseEvent)
public void paint(Graphicsg)
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
Caret
g - the graphics context
damage(java.awt.Rectangle)
public void install(JTextComponentc)
install in interface
Caret
c - the component
Caret.install(javax.swing.text.JTextComponent)
public void deinstall(JTextComponentc)
deinstall in interface
Caret
c - the component
Caret.deinstall(javax.swing.text.JTextComponent)
public void addChangeListener(ChangeListenerl)
addChangeListener in interface
Caret
l - the listener
Caret.addChangeListener(javax.swing.event.ChangeListener)
public void removeChangeListener(ChangeListenerl)
removeChangeListener in interface
Caret
l - the listener
Caret.removeChangeListener(javax.swing.event.ChangeListener)
public ChangeListener[] getChangeListeners()
ChangeListeners or an empty array if no change listeners are currently registered
addChangeListener(javax.swing.event.ChangeListener),
removeChangeListener(javax.swing.event.ChangeListener)
protected void fireStateChanged()
EventListenerList
public <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.EventListener
getChangeListeners()
public void setSelectionVisible(boolean vis)
setSelectionVisible in interface
Caret
vis - the new visibility
public boolean isSelectionVisible()
isSelectionVisible in interface
Caret
public 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
false
isVisible()
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
Caret
Caret.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
Caret
e - the visibility specifier
isActive(),
Caret.setVisible(boolean)
public void setBlinkRate(int rate)
setBlinkRate in interface
Caret
rate - the rate in milliseconds, 0 to stop blinking
Caret.setBlinkRate(int)
public int getBlinkRate()
getBlinkRate in interface
Caret
Caret.getBlinkRate()
public int getDot()
getDot in interface
Caret
Caret.getDot()
public int getMark()
getMark in interface
Caret
Caret.getMark()
public void setDot(int dot)
setDot in interface
Caret
dot - the position >= 0
setDot(int, Position.Bias),
Caret.setDot(int)
public void moveDot(int dot)
moveDot in interface
Caret
dot - the position >= 0
moveDot(int, javax.swing.text.Position.Bias),
Caret.moveDot(int)
public void moveDot(int dot,
Position.Bias dotBias)
dot - the position >= 0
dotBias - the bias for this position, not
null
IllegalArgumentException - if the bias is
null
Caret.moveDot(int)
public void setDot(int dot,
Position.Bias dotBias)
dot - the position >= 0
dotBias - the bias for this position, not
null
IllegalArgumentException - if the bias is
null
Caret.setDot(int)
public Position.Bias getDotBias()
public Position.Bias getMarkBias()
public void setMagicCaretPosition(Pointp)
setMagicCaretPosition in interface
Caret
p - the position
getMagicCaretPosition()
public PointgetMagicCaretPosition()
getMagicCaretPosition in interface
Caret
Caret.setMagicCaretPosition(java.awt.Point)
public boolean equals(Objectobj)
equals in class
Rectangle
obj - the object to compare this font with
true if the objects are equal;
false otherwise
Object.hashCode() ,
HashMap