/*
* Copyright 1999-2015 dangdang.com.
* <p>
* 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.
* </p>
*/
package com.dangdang.ddframe.job.lite.internal.election;
import com.dangdang.ddframe.job.lite.internal.listener.AbstractJobListener;
import com.dangdang.ddframe.job.lite.internal.listener.AbstractListenerManager;
import com.dangdang.ddframe.job.lite.internal.schedule.JobRegistry;
import com.dangdang.ddframe.job.lite.internal.server.ServerNode;
import com.dangdang.ddframe.job.lite.internal.server.ServerService;
import com.dangdang.ddframe.job.lite.internal.server.ServerStatus;
import com.dangdang.ddframe.job.reg.base.CoordinatorRegistryCenter;
import org.apache.curator.framework.recipes.cache.TreeCacheEvent.Type;
/**
* 主节点选举监听管理器.
*
* @author zhangliang
*/
public final class ElectionListenerManager extends AbstractListenerManager {
private final String jobName;
private final LeaderNode leaderNode;
private final ServerNode serverNode;
private final LeaderService leaderService;
private final ServerService serverService;
public ElectionListenerManager(final CoordinatorRegistryCenter regCenter, final String jobName) {
super(regCenter, jobName);
this.jobName = jobName;
leaderNode = new LeaderNode(jobName);
serverNode = new ServerNode(jobName);
leaderService = new LeaderService(regCenter, jobName);
serverService = new ServerService(regCenter, jobName);
}
@Override
public void start() {
addDataListener(new LeaderElectionJobListener());
addDataListener(new LeaderAbdicationJobListener());
}
class LeaderElectionJobListener extends AbstractJobListener {
@Override
protected void dataChanged(final String path, final Type eventType, final String data) {
if (!JobRegistry.getInstance().isShutdown(jobName) && (isActiveElection(path, data) || isPassiveElection(path, eventType))) {
leaderService.electLeader();
}
}
private boolean isActiveElection(final String path, final String data) {
return !leaderService.hasLeader() && isLocalServerEnabled(path, data);
}
private boolean isPassiveElection(final String path, final Type eventType) {
return isLeaderCrashed(path, eventType) && serverService.isAvailableServer(JobRegistry.getInstance().getJobInstance(jobName).getIp());
}
private boolean isLeaderCrashed(final String path, final Type eventType) {
return leaderNode.isLeaderInstancePath(path) && Type.NODE_REMOVED == eventType;
}
private boolean isLocalServerEnabled(final String path, final String data) {
return serverNode.isLocalServerPath(path) && !ServerStatus.DISABLED.name().equals(data);
}
}
class LeaderAbdicationJobListener extends AbstractJobListener {
@Override
protected void dataChanged(final String path, final Type eventType, final String data) {
if (leaderService.isLeader() && isLocalServerDisabled(path, data)) {
leaderService.removeLeader();
}
}
private boolean isLocalServerDisabled(final String path, final String data) {
return serverNode.isLocalServerPath(path) && ServerStatus.DISABLED.name().equals(data);
}
}
}