| /** |
| * 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; |
| |
| import java.io.IOException; |
| import java.net.InetSocketAddress; |
| import java.net.Socket; |
| |
| import org.apache.hadoop.classification.InterfaceAudience; |
| import org.apache.hadoop.conf.Configuration; |
| import org.apache.hadoop.hdfs.DFSClient.Conf; |
| import org.apache.hadoop.hdfs.protocol.ExtendedBlock; |
| import org.apache.hadoop.hdfs.security.token.block.BlockTokenIdentifier; |
| import org.apache.hadoop.security.token.Token; |
| |
| |
| /** |
| * Utility class to create BlockReader implementations. |
| */ |
| @InterfaceAudience.Private |
| public class BlockReaderFactory { |
| /** |
| * @see #newBlockReader(Conf, Socket, String, ExtendedBlock, Token, long, long, int, boolean, String) |
| */ |
| public static BlockReader newBlockReader( |
| Configuration conf, |
| Socket sock, String file, |
| ExtendedBlock block, Token<BlockTokenIdentifier> blockToken, |
| long startOffset, long len) throws IOException { |
| int bufferSize = conf.getInt(DFSConfigKeys.IO_FILE_BUFFER_SIZE_KEY, |
| DFSConfigKeys.IO_FILE_BUFFER_SIZE_DEFAULT); |
| return newBlockReader(new Conf(conf), |
| sock, file, block, blockToken, startOffset, |
| len, bufferSize, true, ""); |
| } |
| |
| /** |
| * Create a new BlockReader specifically to satisfy a read. |
| * This method also sends the OP_READ_BLOCK request. |
| * |
| * @param conf the DFSClient configuration |
| * @param sock An established Socket to the DN. The BlockReader will not close it normally |
| * @param file File location |
| * @param block The block object |
| * @param blockToken The block token for security |
| * @param startOffset The read offset, relative to block head |
| * @param len The number of bytes to read |
| * @param bufferSize The IO buffer size (not the client buffer size) |
| * @param verifyChecksum Whether to verify checksum |
| * @param clientName Client name |
| * @return New BlockReader instance, or null on error. |
| */ |
| @SuppressWarnings("deprecation") |
| public static BlockReader newBlockReader( |
| Conf conf, |
| Socket sock, String file, |
| ExtendedBlock block, |
| Token<BlockTokenIdentifier> blockToken, |
| long startOffset, long len, |
| int bufferSize, boolean verifyChecksum, |
| String clientName) |
| throws IOException { |
| if (conf.useLegacyBlockReader) { |
| return RemoteBlockReader.newBlockReader( |
| sock, file, block, blockToken, startOffset, len, bufferSize, verifyChecksum, clientName); |
| } else { |
| return RemoteBlockReader2.newBlockReader( |
| sock, file, block, blockToken, startOffset, len, bufferSize, verifyChecksum, clientName); |
| } |
| } |
| |
| /** |
| * File name to print when accessing a block directly (from servlets) |
| * @param s Address of the block location |
| * @param poolId Block pool ID of the block |
| * @param blockId Block ID of the block |
| * @return string that has a file name for debug purposes |
| */ |
| public static String getFileName(final InetSocketAddress s, |
| final String poolId, final long blockId) { |
| return s.toString() + ":" + poolId + ":" + blockId; |
| } |
| } |