@Transactional
  public RequestEntity updateStatus(long requestId, HostRoleStatus status, HostRoleStatus displayStatus) {
    RequestEntity requestEntity = findByPK(requestId);
    requestEntity.setStatus(status);
    requestEntity.setDisplayStatus(displayStatus);
    return merge(requestEntity);
  }
Given a collection of request ids, load the corresponding entities
@param requestIds  the collection of request ids
@param refreshHint {@code true} to hint JPA that the list should be refreshed
@return the list entities. An empty list if the requestIds are not provided
ambari-server/src/main/java/org/apache/ambari/server/orm/dao/RequestDAO.java