[jira] [Created] (TINKERPOP-1471) IncidentToAdjacentStrategy use hidden marker to avoid repeated recursion.

["Marko A. Rodriguez (JIRA)" <ji...@apache.org>]

Marko A. Rodriguez created TINKERPOP-1471:
---------------------------------------------

             Summary: IncidentToAdjacentStrategy use hidden marker to avoid repeated recursion.
                 Key: TINKERPOP-1471
                 URL: https://issues.apache.org/jira/browse/TINKERPOP-1471
             Project: TinkerPop
          Issue Type: Improvement
          Components: process
    Affects Versions: 3.2.2
            Reporter: Marko A. Rodriguez
            Assignee: Daniel Kuppitz


TINKERPOP-1456 introduces the notion that "hidden labels" on steps will be removed from the traversal prior to evaluation. This use of "hidden labels" was necessary for {{SubgraphStrategy}} and it is not always possible to remove the add "hidden labels" in {{SubgraphStrategy}} completely. Thus, prior to evaluation, in hidden labels are removed.

This concept of "hidden labels" is useful for marking steps in a traversal so that  a strategy applied at a child gets information from the strategy applied at a parent.

This can be used to make {{IncidentToAdjacentStrategy}} faster. In particular, the following recursion is called repeatedly for each child.

{code}
  if (TraversalHelper.hasStepOfAssignableClassRecursively(INVALIDATING_STEP_CLASSES, TraversalHelper.getRootTraversal(traversal)))
            return;
{code}

Instead, it would be smart to do this and then, you don't need to recurse from the root traversal over and over again.

{code}
    private final void addMarkerToChildren(final Traversal.Admin<?, ?> traversal) {
        traversal.getStartStep().addLabel(MARKER);
        for (final Step<?, ?> step : traversal.getSteps()) {
            if (step instanceof TraversalParent) {
                ((TraversalParent) step).getLocalChildren().forEach(this::addMarkerToChildren);
                ((TraversalParent) step).getGlobalChildren().forEach(this::addMarkerToChildren);
            }
        }
    }

public void apply(Traversal traversal) {
  if(traversal.getParent() instanceof EmptyStep) {
    boolean mark = TraversalHelper.hasStepOfAssignableClassRecursively(INVALIDATING_STEP_CLASSES, traversal)
    if(mark)  this.addMarkerToChildren(traversal)
  }
  // if the marker exists, don't optimize
  if(traversal.getStartStep().getLabels().contains(MARKER)) {
    traversal.getStartStep().removeLabel(MARKER);
    return;
  }
// else do the rest of the code.
}
{code}



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