cn.lhfei.zookeeper.ConfigWatcher.java Source code

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Here is the source code for cn.lhfei.zookeeper.ConfigWatcher.java

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/*
 * Copyright 2010-2011 the original author or authors.
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */
package cn.lhfei.zookeeper;

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;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

/**
 * @version 0.1
 *
 * @author Hefei Li
 *
 * @since May 3, 2015
 */
public class ConfigWatcher implements Watcher {
    private static final Logger log = LoggerFactory.getLogger(ConfigWatcher.class);

    private ActiveKeyValueStore store;

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

    public void displayConfig() throws InterruptedException, KeeperException {
        String value = store.read(ConfigUpdater.PATH, this);
        log.info("Read {} as {}\n", ConfigUpdater.PATH, value);
    }

    @Override
    public void process(WatchedEvent event) {
        if (event.getType() == EventType.NodeDataChanged) {
            try {
                displayConfig();
            } catch (InterruptedException e) {
                log.error("Interrupted. Exiting.");
                Thread.currentThread().interrupt();
            } catch (KeeperException e) {
                log.error("KeeperException: {}. Exiting.\n", e.getMessage(), 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);
    }
}