question: checks if an user exists in the database concode_field_sep UserDAO dao concode_elem_sep boolean exists concode_elem_sep User user concode_elem_sep String username concode_field_sep User getUser concode_elem_sep void register
target: boolean function ( String arg0 ) { this . username = arg0 ; this . dao = DataAccessDriver . getInstance ( ) . newUserDAO ( ) ; this . user = this . dao . selectByName ( arg0 ) ; this . exists = this . user != null ; return this . exists ; }