BinaryNode.java

class BinaryNode<T> {
	
	private T data;
	private BinaryNode<T> leftChild; 
	private BinaryNode<T> rightChild; 

	public BinaryNode(T data) {
		this(data, null, null); 
	} 
	
	public BinaryNode(T data, BinaryNode<T> leftChild, BinaryNode<T> rightChild) {
		this.data = data;
		this.leftChild = leftChild;
		this.rightChild = rightChild;
	} 

	public T getData() {
		return data;
	} 

	public void setData(T newData) {
		data = newData;
	} 

	public BinaryNode<T> getLeftChild() {
		return leftChild;
	} 

	public void setLeftChild(BinaryNode<T> leftChild) {
		this.leftChild = leftChild;
	} 

	public boolean hasLeftChild() {
		return leftChild != null;
	} 

	public BinaryNode<T> getRightChild() {
		return rightChild;
	} 

	public void setRightChild(BinaryNode<T> rightChild) {
		this.rightChild = rightChild;
	} 

	public boolean hasRightChild() {
		return rightChild != null;
	} 


	public boolean isLeaf() {
		return !hasLeftChild() && !hasRightChild();
		// or: return (leftChild == null) && (rightChild == null);
	} 

	public int getNumberOfNodes() {
		if(isLeaf()) {
			return 1;
		}
		int leftNumber = 0;
		int rightNumber = 0;
		if (leftChild != null) {
			leftNumber = leftChild.getNumberOfNodes();
		}
		if (rightChild != null) {
			rightNumber = rightChild.getNumberOfNodes();
		}
		return 1 + leftNumber + rightNumber;
	} 


	/* assumes a 1-node tree has a height of 1 */
	public int getHeight() {
		return getHeight(this); 
	} 

	private int getHeight(BinaryNode<T> node) {
		if(node==null) {
			return 0;
		} else if(node.isLeaf()) {
			return 1;
		} else {
			return  1 + Math.max(
								getHeight(node.getLeftChild()), 
								getHeight(node.getRightChild())
								);
		}
	} 



}