helper method for subclasses to reduce null checks concode_field_sep PlaceHolder placeHolder concode_field_sep boolean accepts concode_elem_sep Object unpack
Object function ( org . opengis . filter . arg0 . Expression arg0 , Object arg1 , Class arg2 ) { if ( arg0 == null ) return null ; return arg0 . evaluate ( arg1 , arg2 ) ; }