/*
* 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.rpc.monitor;
import java.util.List;
import java.util.concurrent.locks.ReentrantLock;
import org.apache.commons.lang.ClassUtils;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import org.springframework.util.CollectionUtils;
import com.alibaba.otter.shared.arbitrate.impl.config.ArbitrateConfigUtils;
import com.alibaba.otter.shared.arbitrate.impl.setl.ArbitrateFactory;
import com.alibaba.otter.shared.arbitrate.impl.setl.ArbitrateLifeCycle;
import com.alibaba.otter.shared.arbitrate.impl.setl.helper.ReplyProcessQueue;
import com.alibaba.otter.shared.arbitrate.impl.zookeeper.ZooKeeperClient;
import com.alibaba.otter.shared.common.utils.zookeeper.ZkClientx;
/**
* 抽取stage处理中一些共性的内容
*
* @author jianghang 2011-9-21 下午02:16:17
* @version 4.0.0
*/
public abstract class AbstractProcessListener extends ArbitrateLifeCycle implements ProcessListener {
protected static final Logger logger = LoggerFactory.getLogger(AbstractProcessListener.class);
protected ZkClientx zookeeper = ZooKeeperClient.getInstance();
protected ReplyProcessQueue replyProcessIds; // 有响应的processId列表
protected ReentrantLock lock = new ReentrantLock();
protected ProcessMonitor processMonitor;
public AbstractProcessListener(Long pipelineId){
super(pipelineId);
// 设置容量，必须大于并行度，这里设置为并行度的10倍，避免因并行度的运行时变化引起问题
int size = ArbitrateConfigUtils.getParallelism(pipelineId) * 10;
if (size < 100) {
size = 100;
}
replyProcessIds = new ReplyProcessQueue(size);
processMonitor = ArbitrateFactory.getInstance(pipelineId, ProcessMonitor.class);
processMonitor.addListener(this);
processMonitor.reload(); // 触发一下processChanged
}
public void processChanged(List<Long> processIds) {
// 在运行过程中会出现Termin(rollback/restart/shutdown)等信号，仲裁器会删除当前运行的所有process
// 因此需要删除之前已满足条件的队列记录，在具体的event处理时还会再对processId再做一次判断，是否已被废弃
compareReply(processIds);
}
/**
* 阻塞方法，获取对应可以被处理的processId，支持中断处理
*/
public Long waitForProcess() throws InterruptedException {
// take和history.put操作非原子，addReply操作时会出现并发问题，同一个processId插入两次
Long processId = (Long) replyProcessIds.take();
logger.debug("## {} get reply id [{}]", ClassUtils.getShortClassName(this.getClass()), processId);
return processId;
}
protected synchronized void addReply(Long processId) {
boolean isSuccessed = replyProcessIds.offer(processId);
if (isSuccessed) {
logger.debug("## {} add reply id [{}]", ClassUtils.getShortClassName(this.getClass()), processId);
} else {
logger.warn("## {} dup reply id [{}]", ClassUtils.getShortClassName(this.getClass()), processId);
}
}
/**
* 将当前的符合条件的processIds和当前的reply queue进行校对，剔除不在processIds里的内容
*/
protected synchronized void compareReply(List<Long> processIds) {
Object[] replyIds = replyProcessIds.toArray();
for (Object replyId : replyIds) {
if (processIds.contains((Long) replyId) == false) { // 判断reply id是否在当前processId列表中
// 因为存在并发问题，如在执行Listener事件的同时，可能触发了process的创建，这时新建的processId会进入到reply队列中
// 此时接受到的processIds变量为上一个版本的内容，所以会删除新建的process，导致整个通道被挂住
if (CollectionUtils.isEmpty(processIds) == false) {
Long processId = processIds.get(0);
if (processId > (Long) replyId) { // 如果当前最小的processId都大于replyId, processId都是递增创建的
logger.info("## {} remove reply id [{}]", ClassUtils.getShortClassName(this.getClass()),
(Long) replyId);
replyProcessIds.remove((Long) replyId);
}
}
}
}
}
public void destory() {
super.destory();
logger.info("## destory pipeline[{}] , Listener[{}]", getPipelineId(),
ClassUtils.getShortClassName(this.getClass()));
processMonitor.removeListener(this);
replyProcessIds.clear();
}
}