public class

NavigationFilter

extends Object
java.lang.Object
   ↳ javax.swing.text.NavigationFilter

Class Overview

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.

See Also

Summary

Nested Classes
class NavigationFilter.FilterBypass Used as a way to circumvent calling back into the caret to position the cursor. 
Public Constructors
NavigationFilter()
Public Methods
int getNextVisualPositionFrom(JTextComponent text, int pos, Position.Bias bias, int direction, 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.
[Expand]
Inherited Methods
From class java.lang.Object

Public Constructors

public NavigationFilter ()

Public Methods

public int getNextVisualPositionFrom (JTextComponent text, int pos, Position.Bias bias, int direction, Bias[] biasRet)

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
BadLocationException

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

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