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

        Node<K,V> rightChild = node.getRight(index);

        node.setRight(rightChild.getLeft(index), index);

        if (rightChild.getLeft(index) != null) {
            rightChild.getLeft(index).setParent(node, index);
        }

        rightChild.setParent(node.getParent(index), index);

        if (node.getParent(index) == null) {

            // node was the root ... now its right child is the root
            rootNode[index] = rightChild;
        } else if (node.getParent(index).getLeft(index) == node) {
            node.getParent(index).setLeft(rightChild, index);
        } else {
            node.getParent(index).setRight(rightChild, index);
        }

        rightChild.setLeft(node, index);
        node.setParent(rightChild, index);
    }
private void rotateLeft(final Node<K,V> node, final int index) {

        Node<K,V> rightChild = node.getRight(index);

        node.setRight(rightChild.getLeft(index), index);

        if (rightChild.getLeft(index) != null) {
            rightChild.getLeft(index).setParent(node, index);
        }

        rightChild.setParent(node.getParent(index), index);

        if (node.getParent(index) == null) {

            // node was the root ... now its right child is the root
            rootNode[index] = rightChild;
        } else if (node.getParent(index).getLeft(index) == node) {
            node.getParent(index).setLeft(rightChild, index);
        } else {
            node.getParent(index).setRight(rightChild, index);
        }

        rightChild.setLeft(node, index);
        node.setParent(rightChild, index);
    }
do a rotate left. standard fare in the world of balanced trees

@param node the node to be rotated
@param index KEY or VALUE