@Override
  public Collection<String> getServices() {
    Collection<String> services = new HashSet<>();
    for (HostGroup group : getHostGroups().values()) {
      services.addAll(group.getServices());
    }
    return services;
  }
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