javax.swing.text

Class 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

    • 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