System.util.collections.OrderedTree.this C# (CSharp) Method

        public object this[IComparable key]
        {
            get {
                return GetData(key);
            }
            set {
                if(key == null)
                    throw new ArgumentNullException("Key is null");

                // traverse tree - find where node belongs
                int result = 0;
                // create new node
                OrderedTreeNode node = new OrderedTreeNode();
                OrderedTreeNode temp = rbTree; // grab the rbTree node of the tree

                while(temp != sentinelNode) {
                    // find Parent
                    node.Parent = temp;
                    result = key.CompareTo(temp.Key);
                    if(result == 0) {
                        lastNodeFound = temp;
                        temp.Data = value;
                        return;
                    }
                    if(result > 0)
                        temp = temp.Right;
                    else
                        temp = temp.Left;
                }

                // setup node
                node.Key = key;
                node.Data = value;
                node.Left = sentinelNode;
                node.Right = sentinelNode;

                // insert node into tree starting at parent's location
                if(node.Parent != null) {
                    result = node.Key.CompareTo(node.Parent.Key);
                    if(result > 0)
                        node.Parent.Right = node;
                    else
                        node.Parent.Left = node;
                }
                else
                    rbTree = node; // first node added

                RestoreAfterInsert(node); // restore red-black properities

                lastNodeFound = node;

                intCount = intCount + 1;
            }
        }