@Override
public void apply(final Traversal<?, ?> traversal, final TraversalEngine engine) {
TraversalHelper.getStepsOfClass(LocalRangeStep.class, traversal)
.forEach(
localRangeStep -> {
Step previousStep = localRangeStep.getPreviousStep();
while (!previousStep.equals(EmptyStep.instance())
&& !(previousStep instanceof PropertiesStep)
&& !(previousStep instanceof VertexStep)) {
previousStep = previousStep.getPreviousStep();
// TODO: check for not filtering/sideEffect steps and throw an exception?
}
if (previousStep instanceof VertexStep) {
VertexStep vertexStep = (VertexStep) previousStep;
if (vertexStep.getReturnClass().equals(Edge.class)) {
localRangeStep.setDirection(vertexStep.getDirection());
} else {
throw new IllegalStateException(
"LocalRangeStep must follow a VertexStep that produces edges, not vertices");
}
} else if (previousStep instanceof PropertiesStep) {
// do nothing, all is good
} else {
throw new IllegalStateException(
"LocalRangeStep must follow a VertexStep or PropertiesStep");
}
});
}
@Override
public default void remove() {
try {
this.applyStrategies(TraversalEngine.STANDARD);
final Step<?, E> endStep = TraversalHelper.getEnd(this);
while (true) {
final Object object = endStep.next().get();
if (object instanceof Element) ((Element) object).remove();
else if (object instanceof Property) ((Property) object).remove();
else {
throw new IllegalStateException(
"The following object does not have a remove() method: " + object);
}
}
} catch (final NoSuchElementException ignored) {
}
}
public <S> Traverser.Admin<S> generate(final S start, final Step<?, S> startStep) {
return new PathTraverser<>(startStep.getLabel(), start, startStep.getTraversal().sideEffects());
}