private void discoverNodeRelationships(LinkedList<Node> queue) {
        Set<Node> visiting = new HashSet<>();
        while (!queue.isEmpty()) {
            Node node = queue.getFirst();
            node.prepareForScheduling();
            if (node.getDependenciesProcessed() || node.isCannotRunInAnyPlan()) {
                // Have already visited this node or have already executed it - skip it
                queue.removeFirst();

        dependentNodes.visitAllNodes(visitor);
    }

    /**
     * Called prior to attempting to schedule a node.
     */
    public void prepareForScheduling() {
        ExecutionState initialState = getInitialState();
        if (initialState != null) {
            state = initialState;
        }
    }

    @Nullable