public Collection<StageEntity> getStages() {
    ensureInitialized();
    Collection<StageEntity> stages = new ArrayList<>();
    for (LogicalRequest logicalRequest : allRequests.values()) {
      stages.addAll(logicalRequest.getStageEntities());
    }
    return stages;
  }
Currently we are just returning all stages for all requests
and relying on the StageResourceProvider to convert each to a resource and do a predicate eval on each.
ambari-server/src/main/java/org/apache/ambari/server/topology/TopologyManager.java