code: protected String getClusterName(Object object) {
  		StandardEvaluationContext context = new StandardEvaluationContext(object);
  		Object value = this.clusterNameExpression.getValue(context);
  		if (value != null) {
  			return value.toString();
  		}
  		return null;
  	}
docs: Helper that fetches the cluster name. Cluster is a Turbine concept and not a
  commons concept. By default we choose the amazon serviceId as the cluster. A custom
  implementation can be plugged in by overriding this method.
  @param object cluster whose name should be evaluated
  @return String name of the cluster