src/main/java/com/workplacesystems/utilsj/collections/TransactionalBidiTreeMap.java
private static <K,V> boolean isRightChild(final Node<K,V> node, final int index) {

        return (node == null)
               ? true
               : ((node.getParent(index) == null)
                  ? false
                  : (node == node.getParent(index).getRight(index)));
    }
private static <K,V> boolean isRightChild(final Node<K,V> node, final int index) {

        return (node == null)
               ? true
               : ((node.getParent(index) == null)
                  ? false
                  : (node == node.getParent(index).getRight(index)));
    }
is this node its parent's right 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 right child. If the
node does exist but has no parent ... no, we're not the
non-existent parent's right child. Otherwise (both the
specified node AND its parent exist), check.

@param node the node (may be null) in question
@param index KEY or VALUE