+ * Returns whether the given node is a direct child of this node.
+ *
+ * @param childNode
+ * The child node
+ * @return <code>true</code> if the given node is a direct child of this
+ * node, <code>false</code> otherwise
+ */
+ public boolean hasChildNode(Node<E> childNode);
+
+ /**
+ * Returns the index of the given child node.
+ *
+ * @param childNode
+ * The child node
+ * @return The index of the child node, or <code>-1</code> if the child
+ * node is not a child node of this node
+ */
+ public int getIndexOfChild(Node<E> childNode);
+
+ /**
+ * Returns the index of the child node containing the given element.
+ *
+ * @param element
+ * The element
+ * @return The index of the child node, or <code>-1</code> if the child
+ * node is not a child node of this node
+ */
+ public int getIndexOfChild(E element);
+
+ /**