org.apache.hadoop.hdfs.server.protocol.InterDatanodeProtocol.java Source code

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Here is the source code for org.apache.hadoop.hdfs.server.protocol.InterDatanodeProtocol.java

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/**
 * 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.protocol;

import java.io.IOException;
import org.apache.hadoop.classification.InterfaceAudience;
import org.apache.hadoop.hdfs.DFSConfigKeys;
import org.apache.hadoop.hdfs.protocol.ExtendedBlock;
import org.apache.hadoop.hdfs.server.protocol.BlockRecoveryCommand.RecoveringBlock;
import org.apache.hadoop.security.KerberosInfo;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

/** An inter-datanode protocol for updating generation stamp
 */
@KerberosInfo(serverPrincipal = DFSConfigKeys.DFS_DATANODE_KERBEROS_PRINCIPAL_KEY, clientPrincipal = DFSConfigKeys.DFS_DATANODE_KERBEROS_PRINCIPAL_KEY)
@InterfaceAudience.Private
public interface InterDatanodeProtocol {
    Logger LOG = LoggerFactory.getLogger(InterDatanodeProtocol.class.getName());

    /**
     * Until version 9, this class InterDatanodeProtocol served as both
     * the interface to the DN AND the RPC protocol used to communicate with the 
     * DN.
     * 
     * This class is used by both the DN to insulate from the protocol 
     * serialization.
     * 
     * If you are adding/changing DN's interface then you need to 
     * change both this class and ALSO related protocol buffer
     * wire protocol definition in InterDatanodeProtocol.proto.
     * 
     * For more details on protocol buffer wire protocol, please see 
     * .../org/apache/hadoop/hdfs/protocolPB/overview.html
     */
    public static final long versionID = 6L;

    /**
     * Initialize a replica recovery.
     * 
     * @return actual state of the replica on this data-node or 
     * null if data-node does not have the replica.
     */
    ReplicaRecoveryInfo initReplicaRecovery(RecoveringBlock rBlock) throws IOException;

    /**
     * Update replica with the new generation stamp and length.  
     */
    String updateReplicaUnderRecovery(ExtendedBlock oldBlock, long recoveryId, long newBlockId, long newLength)
            throws IOException;
}