Java™ Platform
Standard Ed. 6

javax.swing.text
Class NavigationFilter

java.lang.Object
  extended by javax.swing.text.NavigationFilter

public class NavigationFilter
extends Object

NavigationFilter can be used to restrict where the cursor can be positioned. When the default cursor positioning actions attempt to reposition the cursor they will call into the NavigationFilter, assuming the JTextComponent has a non-null NavigationFilter set. In this manner the NavigationFilter can effectively restrict where the cursor can be positioned. Similarly DefaultCaret will call into the NavigationFilter when the user is changing the selection to further restrict where the cursor can be positioned.

Subclasses can conditionally call into supers implementation to restrict where the cursor can be placed, or call directly into the FilterBypass.

Since:
1.4
See Also:
Caret, DefaultCaret, View

Nested Class Summary
static class NavigationFilter.FilterBypass
          Used as a way to circumvent calling back into the caret to position the cursor.
 
Constructor Summary
NavigationFilter()
           
 
Method Summary
 int getNextVisualPositionFrom(JTextComponent text, int pos, Position.Bias bias, int direction, Position.Bias[] biasRet)
          Returns the next visual position to place the caret at from an existing position.
 void moveDot(NavigationFilter.FilterBypass fb, int dot, Position.Bias bias)
          Invoked prior to the Caret moving the dot.
 void setDot(NavigationFilter.FilterBypass fb, int dot, Position.Bias bias)
          Invoked prior to the Caret setting the dot.
 
Methods inherited from class java.lang.Object
clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait
 

Constructor Detail

NavigationFilter

public NavigationFilter()
Method Detail

setDot

public void setDot(NavigationFilter.FilterBypass fb,
                   int dot,
                   Position.Bias bias)
Invoked prior to the Caret setting the dot. The default implementation calls directly into the FilterBypass with the passed in arguments. Subclasses may wish to conditionally call super with a different location, or invoke the necessary method on the FilterBypass

Parameters:
fb - FilterBypass that can be used to mutate caret position
dot - the position >= 0
bias - Bias to place the dot at

moveDot

public void moveDot(NavigationFilter.FilterBypass fb,
                    int dot,
                    Position.Bias bias)
Invoked prior to the Caret moving the dot. The default implementation calls directly into the FilterBypass with the passed in arguments. Subclasses may wish to conditionally call super with a different location, or invoke the necessary methods on the FilterBypass.

Parameters:
fb - FilterBypass that can be used to mutate caret position
dot - the position >= 0
bias - Bias for new location

getNextVisualPositionFrom

public int getNextVisualPositionFrom(JTextComponent text,
                                     int pos,
                                     Position.Bias bias,
                                     int direction,
                                     Position.Bias[] biasRet)
                              throws BadLocationException
Returns the next visual position to place the caret at from an existing position. The default implementation simply forwards the method to the root View. Subclasses may wish to further restrict the location based on additional criteria.

Parameters:
text - JTextComponent containing text
pos - Position used in determining next position
bias - Bias used in determining next position
direction - the direction from the current position that can be thought of as the arrow keys typically found on a keyboard. This will be one of the following values:
  • SwingConstants.WEST
  • SwingConstants.EAST
  • SwingConstants.NORTH
  • SwingConstants.SOUTH
biasRet - Used to return resulting Bias of next position
Returns:
the location within the model that best represents the next location visual position
Throws:
BadLocationException
IllegalArgumentException - if direction doesn't have one of the legal values above

Java™ Platform
Standard Ed. 6

Submit a bug or feature
For further API reference and developer documentation, see Java SE Developer Documentation. That documentation contains more detailed, developer-targeted descriptions, with conceptual overviews, definitions of terms, workarounds, and working code examples.

Copyright 2008 Sun Microsystems, Inc. All rights reserved. Use is subject to license terms. Also see the documentation redistribution policy.


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