ConfigWatcher.java

package com.baidu.disconf.core.common.zookeeper.inner;

import java.io.IOException;

import org.apache.zookeeper.KeeperException;
import org.apache.zookeeper.WatchedEvent;
import org.apache.zookeeper.Watcher;
import org.apache.zookeeper.Watcher.Event.EventType;

/**
 * @author liaoqiqi
 * @version 2014-6-16
 */
public class ConfigWatcher implements Watcher {

    private ResilientActiveKeyValueStore store;

    public ConfigWatcher(String hosts) throws IOException, InterruptedException {
        store = new ResilientActiveKeyValueStore(true);
        store.connect(hosts);
    }

    public void displayConfig() throws InterruptedException, KeeperException {

        String value = store.read(ConfigUpdater.PATH, this, null);
        System.out.printf("Read %s as %s\n", ConfigUpdater.PATH, value);
    }

    @Override
    public void process(WatchedEvent event) {

        if (event.getType() == EventType.NodeDataChanged) {
            try {
                displayConfig();
            } catch (InterruptedException e) {
                System.err.println("Interrupted. Exiting.");
                Thread.currentThread().interrupt();
            } catch (KeeperException e) {
                System.err.printf("KeeperException: %s. Exiting.\n", e);
            }
        }

    }

    public static void main(String[] args) throws Exception {

        ConfigWatcher configWatcher = new ConfigWatcher(args[0]);
        configWatcher.displayConfig();

        // stay alive until process is killed or thread is interrupted
        Thread.sleep(Long.MAX_VALUE);
    }
}