Module java.desktop
Package javax.swing.text

Class NavigationFilter

java.lang.Object
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:

  • Constructor Details

    • NavigationFilter

      public NavigationFilter()
      Constructs a NavigationFilter.

  • Method Details

    • 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 - for a bad location within a document model
      IllegalArgumentException - if direction doesn't have one of the legal values above