/**
* Returns the left or right child of a node depending the specified side
*
* @param node Parent Node
* @param side Specified side
* @return Child node based on size
*/
protected TreeNode<K, V> getChildNode(TreeNode<K, V> node, Side side) {
switch (side) {
case LEFT:
return node.getLeftNode();
case RIGHT:
return node.getRightNode();
}
return null;
}
/**
* Joins two trees
*
* @param childNode Child node
* @param parentNode Parent node
* @param side Side of the parent node to join child node to
*/
protected void joinTrees(TreeNode<K, V> childNode, TreeNode<K, V> parentNode, Side side) {
if (parentNode == null) {
root = childNode;
} else {
switch (side) {
case RIGHT:
parentNode.setRightNode(childNode);
break;
case LEFT:
parentNode.setLeftNode(childNode);
break;
}
}
}
@Override
public V put(K key, V value) {
Path<TreeNode<K, V>> path = new Path<TreeNode<K, V>>();
TreeNode<K, V> node = this.findNode(key, path);
if (node == null) {
TreeNode<K, V> newLeaf = new TreeNode<K, V>(key, value);
this.joinTrees(newLeaf, path.getLastParent(), path.getLastSide());
super.size++;
return null;
} else {
V result = node.getValue();
node.setValue(value);
return result;
}
}
/**
* Returns the node with a given key and fills the path variable with the corresponding
* information
*
* @param key Key to search for
* @param path Path variable to fill
* @return The node with a given key
*/
protected TreeNode<K, V> findNode(K key, Path<TreeNode<K, V>> path) {
path.addRightStep(null);
TreeNode<K, V> node = this.root;
while (node != null) {
int comparisonResult = node.getKey().compareTo(key);
if (comparisonResult < 0) {
if (path != null) path.addRightStep(node);
node = node.getRightNode();
} else if (comparisonResult > 0) {
if (path != null) path.addLeftStep(node);
node = node.getLeftNode();
} else {
return node;
}
}
return null;
}
/**
* Deletes a node with the specified key, if one is found, and stores the path traveled path in
* path
*
* @param key Key to remove
* @param path Traveled path
* @return The deleted node's value, if no node was found returns null
*/
protected V delete(K key, Path<TreeNode<K, V>> path) {
TreeNode<K, V> node = this.findNode(key, path);
if (node == null) {
return null;
}
V result = node.getValue();
if (node.getLeftNode() == null) {
this.joinTrees(node.getRightNode(), path.getLastParent(), path.getLastSide());
} else if (node.getRightNode() == null) {
this.joinTrees(node.getLeftNode(), path.getLastParent(), path.getLastSide());
} else {
path.addRightStep(node);
TreeNode<K, V> minNode = this.getLeafBySide(node.getRightNode(), Side.LEFT, path);
node.setKey(minNode.getKey());
node.setValue(minNode.getValue());
this.joinTrees(minNode.getRightNode(), path.getLastParent(), path.getLastSide());
}
super.size--;
return result;
}
@Override
public V get(K key) {
TreeNode<K, V> node = this.findNode(key);
return node != null ? node.getValue() : null;
}