public boolean legalVertex(final Vertex vertex) {
        return !this.graphFilter.hasVertexFilter() || this.legalVertices.contains(vertex.id());
    }
@author Marko A. Rodriguez (http://markorodriguez.com)
tinkergraph-gremlin/src/main/java/org/apache/tinkerpop/gremlin/tinkergraph/process/computer/TinkerGraphComputerView.java