public void setServiceName(String serviceName) {
    this.serviceName = serviceName;
  }
Set the service name. This is only applicable when {@link #isDefault()} is
{@code true}.

@param serviceName
         the service that this is the default group for, or {@code null} if
         this is not a default group.
ambari-server/src/main/java/org/apache/ambari/server/orm/entities/AlertGroupEntity.java