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.IOException; |
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22 | |
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23 | import org.apache.hadoop.fs.FileSystem; |
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24 | import org.apache.hadoop.fs.Path; |
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25 | |
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26 | import org.apache.hadoop.io.SequenceFile; |
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27 | import org.apache.hadoop.io.SequenceFile.CompressionType; |
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28 | import org.apache.hadoop.io.compress.CompressionCodec; |
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29 | import org.apache.hadoop.io.compress.DefaultCodec; |
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30 | import org.apache.hadoop.mapreduce.Job; |
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31 | import org.apache.hadoop.mapreduce.JobContext; |
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32 | import org.apache.hadoop.mapreduce.OutputFormat; |
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33 | import org.apache.hadoop.mapreduce.RecordWriter; |
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34 | import org.apache.hadoop.mapreduce.TaskAttemptContext; |
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35 | import org.apache.hadoop.util.ReflectionUtils; |
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36 | import org.apache.hadoop.conf.Configuration; |
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37 | |
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38 | /** An {@link OutputFormat} that writes {@link SequenceFile}s. */ |
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39 | public class SequenceFileOutputFormat <K,V> extends FileOutputFormat<K, V> { |
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40 | |
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41 | public RecordWriter<K, V> |
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42 | getRecordWriter(TaskAttemptContext context |
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43 | ) throws IOException, InterruptedException { |
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44 | Configuration conf = context.getConfiguration(); |
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45 | |
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46 | CompressionCodec codec = null; |
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47 | CompressionType compressionType = CompressionType.NONE; |
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48 | if (getCompressOutput(context)) { |
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49 | // find the kind of compression to do |
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50 | compressionType = getOutputCompressionType(context); |
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51 | |
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52 | // find the right codec |
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53 | Class<?> codecClass = getOutputCompressorClass(context, |
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54 | DefaultCodec.class); |
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55 | codec = (CompressionCodec) |
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56 | ReflectionUtils.newInstance(codecClass, conf); |
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57 | } |
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58 | // get the path of the temporary output file |
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59 | Path file = getDefaultWorkFile(context, ""); |
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60 | FileSystem fs = file.getFileSystem(conf); |
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61 | final SequenceFile.Writer out = |
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62 | SequenceFile.createWriter(fs, conf, file, |
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63 | context.getOutputKeyClass(), |
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64 | context.getOutputValueClass(), |
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65 | compressionType, |
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66 | codec, |
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67 | context); |
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68 | |
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69 | return new RecordWriter<K, V>() { |
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70 | |
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71 | public void write(K key, V value) |
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72 | throws IOException { |
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73 | |
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74 | out.append(key, value); |
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75 | } |
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76 | |
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77 | public void close(TaskAttemptContext context) throws IOException { |
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78 | out.close(); |
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79 | } |
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80 | }; |
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81 | } |
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82 | |
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83 | /** |
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84 | * Get the {@link CompressionType} for the output {@link SequenceFile}. |
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85 | * @param job the {@link Job} |
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86 | * @return the {@link CompressionType} for the output {@link SequenceFile}, |
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87 | * defaulting to {@link CompressionType#RECORD} |
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88 | */ |
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89 | public static CompressionType getOutputCompressionType(JobContext job) { |
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90 | String val = job.getConfiguration().get("mapred.output.compression.type", |
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91 | CompressionType.RECORD.toString()); |
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92 | return CompressionType.valueOf(val); |
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93 | } |
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94 | |
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95 | /** |
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96 | * Set the {@link CompressionType} for the output {@link SequenceFile}. |
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97 | * @param job the {@link Job} to modify |
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98 | * @param style the {@link CompressionType} for the output |
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99 | * {@link SequenceFile} |
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100 | */ |
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101 | public static void setOutputCompressionType(Job job, |
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102 | CompressionType style) { |
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103 | setCompressOutput(job, true); |
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104 | job.getConfiguration().set("mapred.output.compression.type", |
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105 | style.toString()); |
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106 | } |
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107 | |
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108 | } |
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109 | |
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