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.mapreduce.lib.output; |
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20 | |
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21 | import java.io.DataOutputStream; |
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22 | import java.io.IOException; |
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23 | import java.io.UnsupportedEncodingException; |
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24 | |
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25 | import org.apache.hadoop.conf.Configuration; |
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26 | import org.apache.hadoop.fs.FileSystem; |
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27 | import org.apache.hadoop.fs.Path; |
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28 | import org.apache.hadoop.fs.FSDataOutputStream; |
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29 | |
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30 | import org.apache.hadoop.io.NullWritable; |
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31 | import org.apache.hadoop.io.Text; |
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32 | import org.apache.hadoop.io.compress.CompressionCodec; |
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33 | import org.apache.hadoop.io.compress.GzipCodec; |
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34 | import org.apache.hadoop.mapreduce.OutputFormat; |
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35 | import org.apache.hadoop.mapreduce.RecordWriter; |
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36 | import org.apache.hadoop.mapreduce.TaskAttemptContext; |
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37 | import org.apache.hadoop.util.*; |
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38 | |
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39 | /** An {@link OutputFormat} that writes plain text files. */ |
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40 | public class TextOutputFormat<K, V> extends FileOutputFormat<K, V> { |
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41 | protected static class LineRecordWriter<K, V> |
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42 | extends RecordWriter<K, V> { |
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43 | private static final String utf8 = "UTF-8"; |
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44 | private static final byte[] newline; |
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45 | static { |
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46 | try { |
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47 | newline = "\n".getBytes(utf8); |
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48 | } catch (UnsupportedEncodingException uee) { |
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49 | throw new IllegalArgumentException("can't find " + utf8 + " encoding"); |
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50 | } |
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51 | } |
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52 | |
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53 | protected DataOutputStream out; |
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54 | private final byte[] keyValueSeparator; |
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55 | |
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56 | public LineRecordWriter(DataOutputStream out, String keyValueSeparator) { |
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57 | this.out = out; |
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58 | try { |
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59 | this.keyValueSeparator = keyValueSeparator.getBytes(utf8); |
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60 | } catch (UnsupportedEncodingException uee) { |
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61 | throw new IllegalArgumentException("can't find " + utf8 + " encoding"); |
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62 | } |
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63 | } |
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64 | |
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65 | public LineRecordWriter(DataOutputStream out) { |
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66 | this(out, "\t"); |
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67 | } |
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68 | |
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69 | /** |
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70 | * Write the object to the byte stream, handling Text as a special |
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71 | * case. |
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72 | * @param o the object to print |
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73 | * @throws IOException if the write throws, we pass it on |
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74 | */ |
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75 | private void writeObject(Object o) throws IOException { |
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76 | if (o instanceof Text) { |
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77 | Text to = (Text) o; |
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78 | out.write(to.getBytes(), 0, to.getLength()); |
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79 | } else { |
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80 | out.write(o.toString().getBytes(utf8)); |
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81 | } |
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82 | } |
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83 | |
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84 | public synchronized void write(K key, V value) |
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85 | throws IOException { |
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86 | |
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87 | boolean nullKey = key == null || key instanceof NullWritable; |
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88 | boolean nullValue = value == null || value instanceof NullWritable; |
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89 | if (nullKey && nullValue) { |
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90 | return; |
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91 | } |
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92 | if (!nullKey) { |
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93 | writeObject(key); |
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94 | } |
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95 | if (!(nullKey || nullValue)) { |
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96 | out.write(keyValueSeparator); |
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97 | } |
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98 | if (!nullValue) { |
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99 | writeObject(value); |
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100 | } |
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101 | out.write(newline); |
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102 | } |
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103 | |
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104 | public synchronized |
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105 | void close(TaskAttemptContext context) throws IOException { |
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106 | out.close(); |
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107 | } |
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108 | } |
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109 | |
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110 | public RecordWriter<K, V> |
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111 | getRecordWriter(TaskAttemptContext job |
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112 | ) throws IOException, InterruptedException { |
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113 | Configuration conf = job.getConfiguration(); |
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114 | boolean isCompressed = getCompressOutput(job); |
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115 | String keyValueSeparator= conf.get("mapred.textoutputformat.separator", |
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116 | "\t"); |
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117 | CompressionCodec codec = null; |
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118 | String extension = ""; |
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119 | if (isCompressed) { |
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120 | Class<? extends CompressionCodec> codecClass = |
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121 | getOutputCompressorClass(job, GzipCodec.class); |
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122 | codec = (CompressionCodec) ReflectionUtils.newInstance(codecClass, conf); |
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123 | extension = codec.getDefaultExtension(); |
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124 | } |
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125 | Path file = getDefaultWorkFile(job, extension); |
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126 | FileSystem fs = file.getFileSystem(conf); |
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127 | if (!isCompressed) { |
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128 | FSDataOutputStream fileOut = fs.create(file, false); |
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129 | return new LineRecordWriter<K, V>(fileOut, keyValueSeparator); |
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130 | } else { |
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131 | FSDataOutputStream fileOut = fs.create(file, false); |
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132 | return new LineRecordWriter<K, V>(new DataOutputStream |
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133 | (codec.createOutputStream(fileOut)), |
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134 | keyValueSeparator); |
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135 | } |
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136 | } |
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137 | } |
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138 | |
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