public AddInstanceFleetRequest withClusterId(String clusterId) {
        setClusterId(clusterId);
        return this;
    }
<p>
The unique identifier of the cluster.
</p>

@param clusterId
       The unique identifier of the cluster.
@return Returns a reference to this object so that method calls can be chained together.
aws-java-sdk-emr/src/main/java/com/amazonaws/services/elasticmapreduce/model/AddInstanceFleetRequest.java