[120] | 1 | /** |
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| 2 | * Licensed to the Apache Software Foundation (ASF) under one |
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| 3 | * or more contributor license agreements. See the NOTICE file |
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| 4 | * distributed with this work for additional information |
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| 5 | * regarding copyright ownership. The ASF licenses this file |
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| 6 | * to you under the Apache License, Version 2.0 (the |
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| 7 | * "License"); you may not use this file except in compliance |
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| 8 | * with the License. You may obtain a copy of the License at |
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| 9 | * |
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| 10 | * http://www.apache.org/licenses/LICENSE-2.0 |
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| 11 | * |
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| 12 | * Unless required by applicable law or agreed to in writing, software |
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| 13 | * distributed under the License is distributed on an "AS IS" BASIS, |
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| 14 | * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. |
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| 15 | * See the License for the specific language governing permissions and |
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| 16 | * limitations under the License. |
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| 17 | */ |
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| 18 | |
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| 19 | package org.apache.hadoop.fs.s3; |
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| 20 | |
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| 21 | import java.io.DataInputStream; |
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| 22 | import java.io.File; |
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| 23 | import java.io.FileInputStream; |
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| 24 | import java.io.IOException; |
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| 25 | |
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| 26 | import org.apache.hadoop.conf.Configuration; |
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| 27 | import org.apache.hadoop.fs.FSInputStream; |
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| 28 | import org.apache.hadoop.fs.FileSystem; |
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| 29 | |
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| 30 | class S3InputStream extends FSInputStream { |
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| 31 | |
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| 32 | private FileSystemStore store; |
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| 33 | |
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| 34 | private Block[] blocks; |
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| 35 | |
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| 36 | private boolean closed; |
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| 37 | |
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| 38 | private long fileLength; |
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| 39 | |
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| 40 | private long pos = 0; |
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| 41 | |
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| 42 | private File blockFile; |
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| 43 | |
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| 44 | private DataInputStream blockStream; |
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| 45 | |
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| 46 | private long blockEnd = -1; |
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| 47 | |
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| 48 | private FileSystem.Statistics stats; |
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| 49 | |
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| 50 | @Deprecated |
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| 51 | public S3InputStream(Configuration conf, FileSystemStore store, |
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| 52 | INode inode) { |
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| 53 | this(conf, store, inode, null); |
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| 54 | } |
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| 55 | |
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| 56 | public S3InputStream(Configuration conf, FileSystemStore store, |
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| 57 | INode inode, FileSystem.Statistics stats) { |
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| 58 | |
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| 59 | this.store = store; |
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| 60 | this.stats = stats; |
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| 61 | this.blocks = inode.getBlocks(); |
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| 62 | for (Block block : blocks) { |
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| 63 | this.fileLength += block.getLength(); |
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| 64 | } |
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| 65 | } |
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| 66 | |
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| 67 | @Override |
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| 68 | public synchronized long getPos() throws IOException { |
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| 69 | return pos; |
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| 70 | } |
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| 71 | |
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| 72 | @Override |
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| 73 | public synchronized int available() throws IOException { |
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| 74 | return (int) (fileLength - pos); |
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| 75 | } |
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| 76 | |
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| 77 | @Override |
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| 78 | public synchronized void seek(long targetPos) throws IOException { |
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| 79 | if (targetPos > fileLength) { |
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| 80 | throw new IOException("Cannot seek after EOF"); |
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| 81 | } |
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| 82 | pos = targetPos; |
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| 83 | blockEnd = -1; |
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| 84 | } |
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| 85 | |
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| 86 | @Override |
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| 87 | public synchronized boolean seekToNewSource(long targetPos) throws IOException { |
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| 88 | return false; |
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| 89 | } |
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| 90 | |
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| 91 | @Override |
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| 92 | public synchronized int read() throws IOException { |
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| 93 | if (closed) { |
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| 94 | throw new IOException("Stream closed"); |
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| 95 | } |
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| 96 | int result = -1; |
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| 97 | if (pos < fileLength) { |
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| 98 | if (pos > blockEnd) { |
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| 99 | blockSeekTo(pos); |
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| 100 | } |
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| 101 | result = blockStream.read(); |
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| 102 | if (result >= 0) { |
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| 103 | pos++; |
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| 104 | } |
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| 105 | } |
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| 106 | if (stats != null & result >= 0) { |
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| 107 | stats.incrementBytesRead(1); |
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| 108 | } |
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| 109 | return result; |
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| 110 | } |
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| 111 | |
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| 112 | @Override |
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| 113 | public synchronized int read(byte buf[], int off, int len) throws IOException { |
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| 114 | if (closed) { |
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| 115 | throw new IOException("Stream closed"); |
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| 116 | } |
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| 117 | if (pos < fileLength) { |
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| 118 | if (pos > blockEnd) { |
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| 119 | blockSeekTo(pos); |
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| 120 | } |
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| 121 | int realLen = Math.min(len, (int) (blockEnd - pos + 1)); |
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| 122 | int result = blockStream.read(buf, off, realLen); |
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| 123 | if (result >= 0) { |
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| 124 | pos += result; |
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| 125 | } |
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| 126 | if (stats != null && result > 0) { |
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| 127 | stats.incrementBytesRead(result); |
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| 128 | } |
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| 129 | return result; |
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| 130 | } |
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| 131 | return -1; |
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| 132 | } |
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| 133 | |
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| 134 | private synchronized void blockSeekTo(long target) throws IOException { |
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| 135 | // |
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| 136 | // Compute desired block |
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| 137 | // |
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| 138 | int targetBlock = -1; |
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| 139 | long targetBlockStart = 0; |
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| 140 | long targetBlockEnd = 0; |
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| 141 | for (int i = 0; i < blocks.length; i++) { |
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| 142 | long blockLength = blocks[i].getLength(); |
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| 143 | targetBlockEnd = targetBlockStart + blockLength - 1; |
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| 144 | |
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| 145 | if (target >= targetBlockStart && target <= targetBlockEnd) { |
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| 146 | targetBlock = i; |
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| 147 | break; |
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| 148 | } else { |
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| 149 | targetBlockStart = targetBlockEnd + 1; |
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| 150 | } |
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| 151 | } |
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| 152 | if (targetBlock < 0) { |
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| 153 | throw new IOException( |
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| 154 | "Impossible situation: could not find target position " + target); |
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| 155 | } |
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| 156 | long offsetIntoBlock = target - targetBlockStart; |
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| 157 | |
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| 158 | // read block blocks[targetBlock] from position offsetIntoBlock |
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| 159 | |
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| 160 | this.blockFile = store.retrieveBlock(blocks[targetBlock], offsetIntoBlock); |
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| 161 | |
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| 162 | this.pos = target; |
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| 163 | this.blockEnd = targetBlockEnd; |
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| 164 | this.blockStream = new DataInputStream(new FileInputStream(blockFile)); |
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| 165 | |
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| 166 | } |
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| 167 | |
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| 168 | @Override |
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| 169 | public void close() throws IOException { |
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| 170 | if (closed) { |
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| 171 | return; |
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| 172 | } |
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| 173 | if (blockStream != null) { |
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| 174 | blockStream.close(); |
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| 175 | blockStream = null; |
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| 176 | } |
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| 177 | if (blockFile != null) { |
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| 178 | blockFile.delete(); |
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| 179 | } |
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| 180 | super.close(); |
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| 181 | closed = true; |
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| 182 | } |
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| 183 | |
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| 184 | /** |
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| 185 | * We don't support marks. |
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| 186 | */ |
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| 187 | @Override |
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| 188 | public boolean markSupported() { |
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| 189 | return false; |
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| 190 | } |
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| 191 | |
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| 192 | @Override |
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| 193 | public void mark(int readLimit) { |
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| 194 | // Do nothing |
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| 195 | } |
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| 196 | |
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| 197 | @Override |
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| 198 | public void reset() throws IOException { |
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| 199 | throw new IOException("Mark not supported"); |
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| 200 | } |
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| 201 | |
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| 202 | } |
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