anchor.diff:                  pgsql_listen_lib:validate_dbname(DBName),
                   pgsql_listen_lib:validate_user(User),
                   pgsql_listen_lib:validate_password(Password)],
  -  rabbit_log:info("Validation results: ~p~n", [Validation]),
     case Validation of
       [ok, ok, ok, ok, ok]                   -> ok;
       [{error, Error, Args}, _, _, _, _]     -> {error, Error, Args};
  
positive.code: -module(pgsql_listen_parameters).
  
  -behaviour(rabbit_runtime_parameter).
  
negative.code:   rabbit_policy:validate(VHost, <<"policy">>, Name, Term).
  
  validate_policy(KeyList) ->
    Host     = proplists:get_value(<<"pgsql-listen-host">>, KeyList, none),
    Port     = proplists:get_value(<<"pgsql-listen-port">>, KeyList, none),
    DBName   = proplists:get_value(<<"pgsql-listen-dbname">>, KeyList, none),
  