/**
* 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.protocol;
/**
*
* The Client transfers data to/from datanode using a streaming protocol.
*
*/
public interface DataTransferProtocol {
/** Version for data transfers between clients and datanodes
* This should change when serialization of DatanodeInfo, not just
* when protocol changes. It is not very obvious.
*/
/*
* Version 14:
* OP_REPLACE_BLOCK is sent from the Balancer server to the destination,
* including the block id, source, and proxy.
* OP_COPY_BLOCK is sent from the destination to the proxy, which contains
* only the block id.
* A reply to OP_COPY_BLOCK sends the block content.
* A reply to OP_REPLACE_BLOCK includes an operation status.
*/
public static final int DATA_TRANSFER_VERSION = 14;
// Processed at datanode stream-handler
public static final byte OP_WRITE_BLOCK = (byte) 80;
public static final byte OP_READ_BLOCK = (byte) 81;
public static final byte OP_READ_METADATA = (byte) 82;
public static final byte OP_REPLACE_BLOCK = (byte) 83;
public static final byte OP_COPY_BLOCK = (byte) 84;
public static final byte OP_BLOCK_CHECKSUM = (byte) 85;
public static final int OP_STATUS_SUCCESS = 0;
public static final int OP_STATUS_ERROR = 1;
public static final int OP_STATUS_ERROR_CHECKSUM = 2;
public static final int OP_STATUS_ERROR_INVALID = 3;
public static final int OP_STATUS_ERROR_EXISTS = 4;
public static final int OP_STATUS_CHECKSUM_OK = 5;
}