code: public ModelNode getAttribute(boolean runtime, String attributeName, Address address) throws Exception {
          final ModelNode op = createReadAttributeRequest(runtime, attributeName, address);
          final ModelNode results = execute(op);
          if (isSuccess(results)) {
              return getResults(results);
          } else {
              throw new FailureException(results, "Failed to get attribute [" + attributeName + "] from [" + address
                      + "]");
          }
      }
docs: Convienence method that allows you to obtain a single attribute's value from a resource.
  
  @param runtime if <code>true</code>, the attribute to be retrieved is a runtime attribute
  @param attributeName the attribute whose value is to be returned
  @param address identifies the resource
  @return the attribute value
  
  @throws Exception if failed to obtain the attribute value