hadoop ActiveState 源码
haddop ActiveState 代码
文件路径：/hadoop-hdfs-project/hadoop-hdfs/src/main/java/org/apache/hadoop/hdfs/server/namenode/ha/ActiveState.java
/**
* Licensed to the Apache Software Foundation (ASF) under one
* or more contributor license agreements. See the NOTICE file
* distributed with this work for additional information
* regarding copyright ownership. The ASF licenses this file
* to you 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 org.apache.hadoop.hdfs.server.namenode.ha;
import java.io.IOException;
import org.apache.hadoop.classification.InterfaceAudience;
import org.apache.hadoop.ha.HAServiceProtocol.HAServiceState;
import org.apache.hadoop.ha.ServiceFailedException;
import org.apache.hadoop.hdfs.server.namenode.NameNode;
import org.apache.hadoop.hdfs.server.namenode.NameNode.OperationCategory;
/**
* Active state of the namenode. In this state, namenode provides the namenode
* service and handles operations of type {@link OperationCategory#WRITE} and
* {@link OperationCategory#READ}.
*/
@InterfaceAudience.Private
public class ActiveState extends HAState {
public ActiveState() {
super(HAServiceState.ACTIVE);
}
@Override
public void checkOperation(HAContext context, OperationCategory op) {
return; // All operations are allowed in active state
}
@Override
public boolean shouldPopulateReplQueues() {
return true;
}
@Override
public void setState(HAContext context, HAState s) throws ServiceFailedException {
if (s == NameNode.STANDBY_STATE) {
setStateInternal(context, s);
return;
}
super.setState(context, s);
}
@Override
public void enterState(HAContext context) throws ServiceFailedException {
try {
context.startActiveServices();
} catch (IOException e) {
throw new ServiceFailedException("Failed to start active services", e);
}
}
@Override
public void exitState(HAContext context) throws ServiceFailedException {
try {
context.stopActiveServices();
} catch (IOException e) {
throw new ServiceFailedException("Failed to stop active services", e);
}
}
}
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