@Override
    public TraverserGenerator getTraverserGenerator(final Set<TraverserRequirement> requirements) {
        if (requirements.contains(TraverserRequirement.ONE_BULK)) {
            if (O_OB_S_SE_SL_TraverserGenerator.instance().getProvidedRequirements().containsAll(requirements))
                return O_OB_S_SE_SL_TraverserGenerator.instance();

            if (NL_O_OB_S_SE_SL_TraverserGenerator.instance().getProvidedRequirements().containsAll(requirements))
                return NL_O_OB_S_SE_SL_TraverserGenerator.instance();

            if (LP_O_OB_S_SE_SL_TraverserGenerator.instance().getProvidedRequirements().containsAll(requirements))
                return LP_O_OB_S_SE_SL_TraverserGenerator.instance();

            if (LP_NL_O_OB_S_SE_SL_TraverserGenerator.instance().getProvidedRequirements().containsAll(requirements))
                return LP_NL_O_OB_S_SE_SL_TraverserGenerator.instance();

            if (LP_O_OB_P_S_SE_SL_TraverserGenerator.instance().getProvidedRequirements().containsAll(requirements))
                return LP_O_OB_P_S_SE_SL_TraverserGenerator.instance();

            if (LP_NL_O_OB_P_S_SE_SL_TraverserGenerator.instance().getProvidedRequirements().containsAll(requirements))
                return LP_NL_O_OB_P_S_SE_SL_TraverserGenerator.instance();
        } else {
            if (B_O_TraverserGenerator.instance().getProvidedRequirements().containsAll(requirements))
                return B_O_TraverserGenerator.instance();

            if (B_O_S_SE_SL_TraverserGenerator.instance().getProvidedRequirements().containsAll(requirements))
                return B_O_S_SE_SL_TraverserGenerator.instance();

            if (B_NL_O_S_SE_SL_TraverserGenerator.instance().getProvidedRequirements().containsAll(requirements))
                return B_NL_O_S_SE_SL_TraverserGenerator.instance();

            if (B_LP_O_S_SE_SL_TraverserGenerator.instance().getProvidedRequirements().containsAll(requirements))
                return B_LP_O_S_SE_SL_TraverserGenerator.instance();

            if (B_LP_NL_O_S_SE_SL_TraverserGenerator.instance().getProvidedRequirements().containsAll(requirements))
                return B_LP_NL_O_S_SE_SL_TraverserGenerator.instance();

            if (B_LP_O_P_S_SE_SL_TraverserGenerator.instance().getProvidedRequirements().containsAll(requirements))
                return B_LP_O_P_S_SE_SL_TraverserGenerator.instance();

            if (B_LP_NL_O_P_S_SE_SL_TraverserGenerator.instance().getProvidedRequirements().containsAll(requirements))
                return B_LP_NL_O_P_S_SE_SL_TraverserGenerator.instance();
        }

        throw new IllegalStateException("The provided traverser generator factory does not support the requirements of the traversal: " + this.getClass().getCanonicalName() + requirements);
    }
@author Marko A. Rodriguez (http://markorodriguez.com)
gremlin-core/src/main/java/org/apache/tinkerpop/gremlin/process/traversal/traverser/util/DefaultTraverserGeneratorFactory.java