/*
* 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;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import org.springframework.util.Assert;
import com.alibaba.otter.shared.arbitrate.impl.ArbitrateEvent;
import com.alibaba.otter.shared.arbitrate.impl.setl.monitor.MainstemMonitor;
import com.alibaba.otter.shared.arbitrate.impl.setl.monitor.PermitMonitor;
import com.alibaba.otter.shared.arbitrate.model.MainStemEventData;
import com.alibaba.otter.shared.common.model.config.channel.ChannelStatus;
/**
* 主导线程信号控制
*
* @author jianghang 2011-8-9 下午05:16:16
*/
public class MainStemArbitrateEvent implements ArbitrateEvent {
private static final Logger logger = LoggerFactory.getLogger(MainStemArbitrateEvent.class);
/**
* <pre>
* 算法:
* 1. 检查当前的Permit，阻塞等待其授权(解决Channel的pause状态处理)
* 2. 尝试创建对应的mainStem节点(非持久化节点)
* a. 如果创建成功，则直接构造结果返回
* b. 如果创建失败，则关注该节点的exist信号. 继续执行步骤2
* </pre>
*/
public void await(Long pipelineId) throws InterruptedException {
Assert.notNull(pipelineId);
PermitMonitor permitMonitor = ArbitrateFactory.getInstance(pipelineId, PermitMonitor.class);
ChannelStatus status = permitMonitor.getChannelPermit(true);
boolean isRuning = check(pipelineId);
if (!status.isStart() && isRuning) {
// 当前状态不为启动，强制设置为taking，下次授权启动后重新追数据
MainStemEventData data = new MainStemEventData();
data.setPipelineId(pipelineId);
data.setStatus(MainStemEventData.Status.TAKEING);
single(data);
permitMonitor.waitForChannelPermit(); // 阻塞等待挂起
return;
} else if (status.isStart() && isRuning) {// 正常状态
return;
} else if (isRuning == false) {
if (!status.isStart()) {
permitMonitor.waitForChannelPermit(); // 阻塞等待挂起
}
MainstemMonitor mainstemMonitor = ArbitrateFactory.getInstance(pipelineId, MainstemMonitor.class);
mainstemMonitor.waitForActive();// 等待自己成为active
status = permitMonitor.getChannelPermit(false);
if (status.isStart()) {
return;
} else {
logger.info("pipelineId[{}] mainstem ignore by status[{}]", new Object[] { pipelineId, status });
await(pipelineId);// 重新进行check一次
}
}
}
/**
* 检查下当前的mainstem是否可以运行(在await获取成功后，每次执行业务之前进行check)
*/
public boolean check(Long pipelineId) {
MainstemMonitor mainstemMonitor = ArbitrateFactory.getInstance(pipelineId, MainstemMonitor.class);
return mainstemMonitor.check();
}
/**
* 更新mainStem的同步状态数据
*/
public void single(MainStemEventData data) {
MainstemMonitor mainstemMonitor = ArbitrateFactory.getInstance(data.getPipelineId(), MainstemMonitor.class);
mainstemMonitor.single(data);
}
/**
* 释放mainStem的节点，重新选择工作节点
*/
public void release(Long pipelineId) {
MainstemMonitor mainstemMonitor = ArbitrateFactory.getInstance(pipelineId, MainstemMonitor.class);
mainstemMonitor.releaseMainstem();
}
}