/*
* Copyright (C) 2010-2101 Alibaba Group Holding Limited.
*
* 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 com.alibaba.otter.shared.arbitrate.impl.setl.monitor;
import java.util.ArrayList;
import java.util.Collections;
import java.util.List;
import java.util.concurrent.ExecutorService;
import org.I0Itec.zkclient.IZkChildListener;
import org.I0Itec.zkclient.exception.ZkNodeExistsException;
import org.apache.commons.lang.ClassUtils;
import org.apache.commons.lang.StringUtils;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import com.alibaba.otter.shared.arbitrate.impl.ArbitrateConstants;
import com.alibaba.otter.shared.arbitrate.impl.setl.monitor.listener.NodeListener;
import com.alibaba.otter.shared.arbitrate.impl.zookeeper.ZooKeeperClient;
import com.alibaba.otter.shared.common.utils.zookeeper.ZkClientx;
/**
* otter所有node节点监控
*
* @author jianghang 2012-8-29 下午01:00:43
* @version 4.1.0
*/
public class NodeMonitor implements Monitor {
private static final Logger logger = LoggerFactory.getLogger(NodeMonitor.class);
private ExecutorService arbitrateExecutor;
private ZkClientx zookeeper = ZooKeeperClient.getInstance();
private List<NodeListener> listeners = Collections.synchronizedList(new ArrayList<NodeListener>());
private volatile List<Long> aliveNodes = new ArrayList<Long>(); // se模块存活的节点
private IZkChildListener childListener;
public NodeMonitor(){
childListener = new IZkChildListener() {
public void handleChildChange(String parentPath, List<String> currentChilds) throws Exception {
if (currentChilds != null) {
initNodes(currentChilds);
}
}
};
List<String> childs = zookeeper.subscribeChildChanges(ArbitrateConstants.NODE_NID_ROOT, childListener);
if (childs == null) {//如果为null，代表系统节点为初始化
try {
zookeeper.createPersistent(ArbitrateConstants.NODE_NID_ROOT, true);
} catch (ZkNodeExistsException e) {
//ignore
}
childs = zookeeper.getChildren(ArbitrateConstants.NODE_NID_ROOT);
}
initNodes(childs);
// syncNodes();// 开始监视node节点的变化
MonitorScheduler.register(this);
}
public void reload() {
try {
initNodes();// 更新数据
} catch (Exception e) {
}
}
public void destory() {
listeners.clear();
zookeeper.unsubscribeChildChanges(ArbitrateConstants.NODE_NID_ROOT, childListener);
MonitorScheduler.unRegister(this);
}
/**
* 返回当前存活的node列表
*/
public List<Long> getAliveNodes(boolean reload) {
if (reload) {
initNodes();
}
return new ArrayList<Long>(aliveNodes);
}
/**
* 返回当前存活的node列表
*/
public List<Long> getAliveNodes() {
return getAliveNodes(false);
}
private void initNodes() {
// 获取一下当前存活的所有node节点，再根据对应pipeline关联的node，检查是否在对应的存活列表里
List<String> nodes = zookeeper.getChildren(ArbitrateConstants.NODE_NID_ROOT);
initNodes(nodes);
}
private synchronized void initNodes(List<String> nodes) {
List<Long> nids = new ArrayList<Long>();
for (String node : nodes) {
if (StringUtils.isNumeric(node)) {
nids.add(Long.valueOf(node));
}
}
Collections.sort(nids);
if (!aliveNodes.equals(nids)) {// 不相同，说明有变化
if (logger.isDebugEnabled()) {
logger.debug("old aliveNodes{} ,current aliveNodes{}", new Object[] { aliveNodes, nids });
}
aliveNodes = nids; // 切换引用，需设置为volatile保证线程安全&可见性
processChanged(nids);// 通知变化
}
}
// private void syncNodes() {
// try {
// List<String> nodes = zookeeper.getChildren(ArbitrateConstants.NODE_NID_ROOT, new AsyncWatcher() {
//
// public void asyncProcess(WatchedEvent event) {
// // 出现session expired/connection losscase下，会触发所有的watcher响应，同时老的watcher会继续保留，所以会导致出现多次watcher响应
// boolean dataChanged = event.getType() == EventType.NodeDataChanged
// || event.getType() == EventType.NodeDeleted
// || event.getType() == EventType.NodeCreated
// || event.getType() == EventType.NodeChildrenChanged;
// if (dataChanged) {
// syncNodes();// 继续关注node节点变化
// }
// }
// });
//
// initNodes(nodes);
// } catch (KeeperException e) {
// syncNodes();
// logger.error("", e);
// } catch (InterruptedException e) {
// // ignore
// }
// }
// ======================== listener处理 ======================
public void addListener(NodeListener listener) {
if (logger.isDebugEnabled()) {
logger.debug("## pipeline[{}] add listener [{}]", ClassUtils.getShortClassName(listener.getClass()));
}
this.listeners.add(listener);
}
public void removeListener(NodeListener listener) {
if (logger.isDebugEnabled()) {
logger.debug("## remove listener [{}]", ClassUtils.getShortClassName(listener.getClass()));
}
this.listeners.remove(listener);
}
private void processChanged(final List<Long> nodes) {
for (final NodeListener listener : listeners) {
// 异步处理
arbitrateExecutor.submit(new Runnable() {
public void run() {
listener.processChanged(nodes);
}
});
}
}
// ========= setter ========
public void setArbitrateExecutor(ExecutorService arbitrateExecutor) {
this.arbitrateExecutor = arbitrateExecutor;
}
}