@Override
        protected boolean filter(final Traverser.Admin<Object> traverser) {
            return null == this.matchKey || traverser.get().equals(this.matchValue);
        }
@author Marko A. Rodriguez (http://markorodriguez.com)
gremlin-core/src/main/java/org/apache/tinkerpop/gremlin/process/traversal/step/filter/WhereTraversalStep.java