private final String emitString() {
        return null == this.emitTraversal ? "emit(false)" : "emit(" + this.emitTraversal + ')';
    }
@author Marko A. Rodriguez (http://markorodriguez.com)
gremlin-core/src/main/java/org/apache/tinkerpop/gremlin/process/traversal/step/branch/RepeatStep.java