private boolean belongsTo(ServiceComponentHost component) {
    return component.getServiceName().equals(serviceName) && component.getServiceComponentName().equals(componentName);
  }
Collect the host names from the cluster where the given alert is allowed to run.
A host is able to run an alert if the service component of the alert is installed on that particular host.
In case of AMBARI server alerts or AGGREGATE alerts, an empty host set is returned.
@return matching host names
ambari-server/src/main/java/org/apache/ambari/server/state/alert/AlertDefinition.java