JAVA BinaryTree

JavaBinaryTree.scala

package t1;

public class JavaBinaryTree{

	static class Empty extends BinaryTreeMap{
		
		protected Empty(){}
		@Override
		public boolean isEmpty(){
			return true;
		}
		@Override
		public String toString(){
			return "Nil";
		}
		
	}
	private static BinaryTreeMap Nil = new Empty();
	
	private static class BinaryTreeMap<K extends Comparable<K>, V> {

		private K key;
		private V value;
		private BinaryTreeMap<K, V> left;
		private BinaryTreeMap<K, V> right;

		private BinaryTreeMap(){}
		
		public boolean isEmpty() {
			return false;
		}

		public BinaryTreeMap(K k, V v, BinaryTreeMap<K, V> l, BinaryTreeMap<K, V> r) {
			key = k;
			value = v;
			left = l;
			right = r;
		}

		public BinaryTreeMap<K, V> insert(K k, V val) {
			if(isEmpty())
				return new BinaryTreeMap<K,V>(k,val,Nil,Nil);
			
			if (k.compareTo(key) == 0)
				return this;
			else if (k.compareTo(key) > 0)
				return new BinaryTreeMap<K, V>(key, value, left, right.insert(k, val));
			else
				return new BinaryTreeMap<K, V>(key, value, left.insert(k, val), right);
		}

		public String toString() {
			return String.format("[ [Tree] (Key : %s), (value : %s), (left : %s), (right : %s) ]", key, value,left,right);
		}

		public V search(K key) {
			return null;
		}

		public V getValue() {
			return value;
		}

	}

	static <K extends Comparable<K>, V> BinaryTreeMap<K, V> makeTree(K key,
			V value) {
		return new BinaryTreeMap<K, V>(key, value, Nil, Nil);
	}

	public static void main(String[] args) {
		BinaryTreeMap<String, String> tree = makeTree("123", "123");

		tree = tree.insert("234", "234");
		tree = tree.insert("345", "234");
		tree = tree.insert("012", "234");

		System.out.println(tree);
	}
}