class EmrClusterDefinitionDaoHelper {

    public List<EmrClusterDefinitionKey> getEmrClusterDefinitionKeys(String namespace)
    {
        // Try to retrieve the relative namespace entity.
        NamespaceEntity namespaceEntity = namespaceDao.getNamespaceByCd(namespace);

        // If namespace entity exists, retrieve EMR cluster definition keys by namespace entity.
        if (namespaceEntity != null)
        {
            return emrClusterDefinitionDao.getEmrClusterDefinitionKeysByNamespace(namespaceEntity);
        }
        else
        {
            return Lists.newArrayList();
        }
    }

}