@Override
    public void apply(final Traversal.Admin<?, ?> traversal) {
        if (!TraversalHelper.onGraphComputer(traversal))
            return;

        if (traversal.getParent() instanceof TraversalVertexProgramStep) {
            if (TraversalHelper.getStepsOfAssignableClassRecursively(GraphStep.class, traversal).size() > 1)
                throw new VerificationException("Mid-traversal V()/E() is currently not supported on GraphComputer", traversal);
            if (TraversalHelper.hasStepOfAssignableClassRecursively(ProfileStep.class, traversal) && TraversalHelper.getStepsOfAssignableClass(VertexProgramStep.class, TraversalHelper.getRootTraversal(traversal)).size() > 1)
                throw new VerificationException("Profiling a multi-VertexProgramStep traversal is currently not supported on GraphComputer", traversal);
        }

        // this is a problem because sideEffect.merge() is transient on the OLAP reduction
        if (TraversalHelper.getRootTraversal(traversal).getTraverserRequirements().contains(TraverserRequirement.ONE_BULK))
            throw new VerificationException("One bulk is currently not supported on GraphComputer: " + traversal, traversal);

        // you can not traverse past the local star graph with localChildren (e.g. by()-modulators).
        if (!TraversalHelper.isGlobalChild(traversal) && !TraversalHelper.isLocalStarGraph(traversal))
            throw new VerificationException("Local traversals may not traverse past the local star-graph on GraphComputer: " + traversal, traversal);

        for (final Step<?, ?> step : traversal.getSteps()) {
            if (step instanceof PathProcessor && ((PathProcessor) step).getMaxRequirement() != PathProcessor.ElementRequirement.ID)
                throw new VerificationException("It is not possible to access more than a path element's id on GraphComputer: " + step + " requires " + ((PathProcessor) step).getMaxRequirement(), traversal);

            if (UNSUPPORTED_STEPS.stream().filter(c -> c.isAssignableFrom(step.getClass())).findFirst().isPresent())
                throw new VerificationException("The following step is currently not supported on GraphComputer: " + step, traversal);

            if (step instanceof SideEffectCapable) {
                final BinaryOperator<?> sideEffectOperator = traversal.getSideEffects().getReducer(((SideEffectCapable<?, ?>) step).getSideEffectKey());
                if (UNSUPPORTED_OPERATORS.stream().filter(o -> o == sideEffectOperator).findFirst().isPresent()) {
                    throw new VerificationException("The following step has an SideEffect operator " + sideEffectOperator + " which is currently not supported on GraphComputer: " + step, traversal);
                }
            }
        }

        Step<?, ?> nextParentStep = traversal.getParent().asStep();
        while (!(nextParentStep instanceof EmptyStep)) {
            if (nextParentStep instanceof PathProcessor && ((PathProcessor) nextParentStep).getMaxRequirement() != PathProcessor.ElementRequirement.ID)
                throw new VerificationException("The following path processor step requires more than the element id on GraphComputer: " + nextParentStep + " requires " + ((PathProcessor) nextParentStep).getMaxRequirement(), traversal);
            nextParentStep = nextParentStep.getNextStep();
        }
    }
@author Marko A. Rodriguez (http://markorodriguez.com)
gremlin-core/src/main/java/org/apache/tinkerpop/gremlin/process/traversal/strategy/verification/ComputerVerificationStrategy.java