/**
* 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;
import java.io.IOException;
import org.apache.hadoop.hdfs.protocol.FSConstants;
import org.apache.hadoop.hdfs.server.common.HdfsConstants;
import org.apache.hadoop.hdfs.server.common.UpgradeObject;
import org.apache.hadoop.hdfs.server.protocol.UpgradeCommand;
/**
* Base class for name-node upgrade objects.
* Data-node upgrades are run in separate threads.
*/
public abstract class UpgradeObjectNamenode extends UpgradeObject {
/**
* Process an upgrade command.
* RPC has only one very generic command for all upgrade related inter
* component communications.
* The actual command recognition and execution should be handled here.
* The reply is sent back also as an UpgradeCommand.
*
* @param command
* @return the reply command which is analyzed on the client side.
*/
public abstract UpgradeCommand processUpgradeCommand(UpgradeCommand command
) throws IOException;
public HdfsConstants.NodeType getType() {
return HdfsConstants.NodeType.NAME_NODE;
}
/**
*/
public UpgradeCommand startUpgrade() throws IOException {
// broadcast that data-nodes must start the upgrade
return new UpgradeCommand(UpgradeCommand.UC_ACTION_START_UPGRADE,
getVersion(), (short)0);
}
protected FSNamesystem getFSNamesystem() {
return FSNamesystem.getFSNamesystem();
}
public void forceProceed() throws IOException {
// do nothing by default
NameNode.LOG.info("forceProceed() is not defined for the upgrade. "
+ getDescription());
}
}