public class NavigationFilter extends Object
NavigationFiltercan 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
JTextComponenthas a non-null
NavigationFilterset. In this manner the
NavigationFiltercan effectively restrict where the cursor can be positioned. Similarly
DefaultCaretwill call into the
NavigationFilterwhen 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
Nested Class SummaryModifier and TypeClassDescription
static classUsed as a way to circumvent calling back into the caret to position the cursor.
Method SummaryModifier and TypeMethodDescription
intReturns the next visual position to place the caret at from an existing position.
voidInvoked prior to the Caret moving the dot.
voidInvoked prior to the Caret setting the dot.
NavigationFilterpublic NavigationFilter()Constructs a
getNextVisualPositionFrompublic int getNextVisualPositionFrom(JTextComponent text, int pos, Position.Bias bias, int direction, Position.Bias biasRet) throws BadLocationExceptionReturns 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.
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:
biasRet- Used to return resulting Bias of next position
- the location within the model that best represents the next location visual position
BadLocationException- for a bad location within a document model
directiondoesn't have one of the legal values above