Method isLeftChild

src/java/org/apache/poi/util/BinaryTree.java:705–713

is this node its parent's left child? mind you, the node, or its parent, may not exist. no problem. if the node doesn't exist ... it's its non-existent parent's left child. If the node does exist but has no parent ... no, we're not the non-existent parent's left child. Otherwise (both the specified

(Node node, int index)

     * @param index _KEY or _VALUE
     */
    private static boolean isLeftChild(Node node, int index) {
        if (node == null) {
            return true;
        }
        if (node.getParent(index) == null) {
            return false;
        }
        return node == node.getParent(index).getLeft(index);
    }

    /**
     * is this node its parent's right child? mind you, the node, or