public Result getResult(String id) {
    if (results.containsKey(id)) {
      return results.get(id);
    }

    throw new NoSuchElementException();
  }
OperationStatusMetaData is data to return as the status of an operation invoked on a set of resources
while processing a REST API request.
<p>
Zero or more results may be set as part of the data.
ambari-server/src/main/java/org/apache/ambari/server/controller/internal/OperationStatusMetaData.java