private static ComponentExclude excludeComponent(String excludedServiceName, String excludedComponentName, String excludedHostName) {
    return (serviceName, componentName, hosts) -> excludedServiceName.equals(serviceName)
      && excludedComponentName.equals(componentName)
      && hostNames(hosts).equals(singletonList(excludedHostName));
  }
Populates the identities with an empty list
ambari-server/src/main/java/org/apache/ambari/server/controller/utilities/RemovableIdentities.java