code: public void setSocketBindingPortExpression(String socketBindingGroupName, String socketBindingName,
          String sysPropName, int port) throws Exception {
  
          String portValue;
          if (sysPropName != null) {
              portValue = "${" + sysPropName + ":" + port + "}";
          } else {
              portValue = String.valueOf(port);
          }
  
          Address addr = Address.root().add(SOCKET_BINDING_GROUP, socketBindingGroupName, SOCKET_BINDING,
              socketBindingName);
          ModelNode request = createWriteAttributeRequest(PORT, portValue, addr);
          ModelNode results = execute(request);
          if (!isSuccess(results)) {
              throw new FailureException(results);
          }
          return; // everything is OK
      }
docs: Sets the port number for the named socket binding found in the named socket binding group.
  If sysPropName is null, this simply sets the port number explicitly to the given port number.
  If sysPropName is not null, this sets the port to the expression "${sysPropName:port}".
  
  @param socketBindingGroupName the name of the socket binding group that has the named socket binding
  @param socketBindingName the name of the socket binding whose port is to be set
  @param sysPropName the name of the system property whose value is to be the port number
  @param port the default port number if the sysPropName is not defined
  @throws Exception any error