@Override
  public Set<SubResourceDefinition> getSubResourceDefinitions() {
    final Set<SubResourceDefinition> subResourceDefintions = new HashSet<>();
    subResourceDefintions.add(new SubResourceDefinition(Resource.Type.RepositoryVersion));
    return subResourceDefintions;
  }
Stack Version Resource Definition for hosts and clusters.
ambari-server/src/main/java/org/apache/ambari/server/api/resources/ComponentStackVersionResourceDefinition.java