question: public FormatResult applyMask ( String mask , String value , String oldValue , Integer cursorIndex ) { if ( mask == null || value == null ) { return null ; } if ( oldValue . length ( ) > value . length ( ) ) { return new FormatResult ( value , null ) ; } value = ( String ) getMaskOrGetCursorIndex ( mask , value , cursorIndex , true ) ; cursorIndex = ( Integer ) getMaskOrGetCursorIndex ( mask , value , cursorIndex , false ) ; return new FormatResult ( value , cursorIndex ) ; }
target:  Will apply a mask a returns formatresult