Zookeeper Watcher Problem

I want information about watcher,
I must develope a MapReduce Yarn application.
I open the zookeeper connection in the main method in WordCount.java class. After I have a Map.java class with the map method. In map method i open a new zookeeper connection in this way:

final CountDownLatch connectedSignal = new CountDownLatch(1);
ZooKeeper zk = new ZooKeeper("localhost:2181", 30000, new Watcher() {
@Override
public void process(WatchedEvent event) {
if (event.getState() == Watcher.Event.KeeperState.SyncConnected) {
connectedSignal.countDown();

});

Map class implements Watcher and i add at the end of Map class the process method. If i change data on the znode my process method isn’t called!
I wrong sure to set the Watcher :(