public Collection<ConfigProperty> getRequiredConfigurationProperties(String service) {
    Collection<ConfigProperty> requiredConfigProperties = new HashSet<>();
    Map<String, Map<String, ConfigProperty>> serviceProperties = requiredServiceConfigurations.get(service);
    if (serviceProperties != null) {
      for (Map.Entry<String, Map<String, ConfigProperty>> typePropertiesEntry : serviceProperties.entrySet()) {
        requiredConfigProperties.addAll(typePropertiesEntry.getValue().values());
      }
    }
    return requiredConfigProperties;
  }
Get all required config properties for the specified service.

@param service  service name

@return collection of all required properties for the given service
ambari-server/src/main/java/org/apache/ambari/server/controller/internal/Stack.java