package bintree;

public class BinTreeFullSync implements BinTree {

	private static class Node {
		final int value;
		int occ;
		Node left, right;

		private Node(int value, int initOcc) {
			this.value = value;
			occ = initOcc;
		}
	}

	private final Node root = new Node(0, 0);

	public synchronized void insert(int value) {
		Node n = root;
		while (true) {
			int nval = n.value;
			if (value == nval) {
				n.occ++;
				return;
			} 
			else if (value < nval) {
				if (n.left == null) {
					n.left = new Node(value, 1);
					return;
				}
				n = n.left;
			} 
			else { // value > nval
				if (n.right == null) {
					n.right = new Node(value, 1);
					return;
				}
				n = n.right;
			} 
		}
	}

	public synchronized int occurs(int value) {
		Node n = root;
		do {
			int nval = n.value;
			if (value == nval) {
				return n.occ++;
			}
			n = (value < nval) ? n.left : n.right;
		} while (n != null);
		// value not found
		return 0;
	}
}