@Override
      public boolean apply(StageEntityPK stageEntityPK) {
        return stageEntityPK.getRequestId().equals(requestID);
      }
Filters list of {@link Stage} to list of {@link StageEntityPK}
@param requestID requestId
@return  list of StageEntityPK
ambari-server/src/main/java/org/apache/ambari/server/events/listeners/tasks/TaskStatusListener.java