@Override
  public Collection<String> getComponents(String service) {
    Collection<String> components = new HashSet<>();
    for (HostGroup group : getHostGroupsForService(service)) {
      components.addAll(group.getComponents(service));
    }

    return components;
  }
Get all services represented in blueprint.

@return collections of all services provided by topology
ambari-server/src/main/java/org/apache/ambari/server/topology/BlueprintImpl.java