@Override
    public List<String> ls(final String pattern) {
        final List<String> rdds = new ArrayList<>();

        forEachMatching( pattern, rdd -> rdds.add(rdd.name() + " [" + rdd.getStorageLevel().description() + "]"));

        return rdds;
    }
@author Marko A. Rodriguez (http://markorodriguez.com)
spark-gremlin/src/main/java/org/apache/tinkerpop/gremlin/spark/structure/io/SparkContextStorage.java