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.input; |
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20 | |
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21 | import java.io.IOException; |
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22 | import java.util.ArrayList; |
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23 | import java.util.List; |
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24 | |
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25 | import org.apache.commons.logging.Log; |
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26 | import org.apache.commons.logging.LogFactory; |
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27 | import org.apache.hadoop.conf.Configuration; |
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28 | import org.apache.hadoop.fs.FileStatus; |
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29 | import org.apache.hadoop.fs.FileSystem; |
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30 | import org.apache.hadoop.fs.Path; |
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31 | import org.apache.hadoop.fs.PathFilter; |
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32 | import org.apache.hadoop.fs.BlockLocation; |
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33 | import org.apache.hadoop.mapreduce.InputFormat; |
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34 | import org.apache.hadoop.mapreduce.InputSplit; |
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35 | import org.apache.hadoop.mapreduce.Job; |
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36 | import org.apache.hadoop.mapreduce.JobContext; |
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37 | import org.apache.hadoop.mapreduce.Mapper; |
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38 | import org.apache.hadoop.util.ReflectionUtils; |
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39 | import org.apache.hadoop.util.StringUtils; |
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40 | |
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41 | /** |
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42 | * A base class for file-based {@link InputFormat}s. |
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43 | * |
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44 | * <p><code>FileInputFormat</code> is the base class for all file-based |
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45 | * <code>InputFormat</code>s. This provides a generic implementation of |
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46 | * {@link #getSplits(JobContext)}. |
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47 | * Subclasses of <code>FileInputFormat</code> can also override the |
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48 | * {@link #isSplitable(JobContext, Path)} method to ensure input-files are |
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49 | * not split-up and are processed as a whole by {@link Mapper}s. |
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50 | */ |
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51 | public abstract class FileInputFormat<K, V> extends InputFormat<K, V> { |
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52 | |
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53 | private static final Log LOG = LogFactory.getLog(FileInputFormat.class); |
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54 | |
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55 | private static final double SPLIT_SLOP = 1.1; // 10% slop |
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56 | |
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57 | private static final PathFilter hiddenFileFilter = new PathFilter(){ |
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58 | public boolean accept(Path p){ |
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59 | String name = p.getName(); |
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60 | return !name.startsWith("_") && !name.startsWith("."); |
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61 | } |
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62 | }; |
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63 | |
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64 | /** |
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65 | * Proxy PathFilter that accepts a path only if all filters given in the |
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66 | * constructor do. Used by the listPaths() to apply the built-in |
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67 | * hiddenFileFilter together with a user provided one (if any). |
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68 | */ |
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69 | private static class MultiPathFilter implements PathFilter { |
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70 | private List<PathFilter> filters; |
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71 | |
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72 | public MultiPathFilter(List<PathFilter> filters) { |
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73 | this.filters = filters; |
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74 | } |
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75 | |
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76 | public boolean accept(Path path) { |
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77 | for (PathFilter filter : filters) { |
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78 | if (!filter.accept(path)) { |
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79 | return false; |
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80 | } |
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81 | } |
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82 | return true; |
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83 | } |
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84 | } |
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85 | |
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86 | /** |
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87 | * Get the lower bound on split size imposed by the format. |
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88 | * @return the number of bytes of the minimal split for this format |
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89 | */ |
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90 | protected long getFormatMinSplitSize() { |
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91 | return 1; |
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92 | } |
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93 | |
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94 | /** |
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95 | * Is the given filename splitable? Usually, true, but if the file is |
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96 | * stream compressed, it will not be. |
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97 | * |
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98 | * <code>FileInputFormat</code> implementations can override this and return |
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99 | * <code>false</code> to ensure that individual input files are never split-up |
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100 | * so that {@link Mapper}s process entire files. |
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101 | * |
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102 | * @param context the job context |
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103 | * @param filename the file name to check |
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104 | * @return is this file splitable? |
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105 | */ |
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106 | protected boolean isSplitable(JobContext context, Path filename) { |
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107 | return true; |
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108 | } |
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109 | |
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110 | /** |
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111 | * Set a PathFilter to be applied to the input paths for the map-reduce job. |
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112 | * @param job the job to modify |
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113 | * @param filter the PathFilter class use for filtering the input paths. |
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114 | */ |
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115 | public static void setInputPathFilter(Job job, |
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116 | Class<? extends PathFilter> filter) { |
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117 | job.getConfiguration().setClass("mapred.input.pathFilter.class", filter, |
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118 | PathFilter.class); |
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119 | } |
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120 | |
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121 | /** |
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122 | * Set the minimum input split size |
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123 | * @param job the job to modify |
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124 | * @param size the minimum size |
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125 | */ |
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126 | public static void setMinInputSplitSize(Job job, |
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127 | long size) { |
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128 | job.getConfiguration().setLong("mapred.min.split.size", size); |
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129 | } |
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130 | |
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131 | /** |
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132 | * Get the minimum split size |
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133 | * @param job the job |
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134 | * @return the minimum number of bytes that can be in a split |
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135 | */ |
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136 | public static long getMinSplitSize(JobContext job) { |
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137 | return job.getConfiguration().getLong("mapred.min.split.size", 1L); |
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138 | } |
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139 | |
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140 | /** |
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141 | * Set the maximum split size |
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142 | * @param job the job to modify |
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143 | * @param size the maximum split size |
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144 | */ |
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145 | public static void setMaxInputSplitSize(Job job, |
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146 | long size) { |
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147 | job.getConfiguration().setLong("mapred.max.split.size", size); |
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148 | } |
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149 | |
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150 | /** |
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151 | * Get the maximum split size. |
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152 | * @param context the job to look at. |
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153 | * @return the maximum number of bytes a split can include |
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154 | */ |
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155 | public static long getMaxSplitSize(JobContext context) { |
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156 | return context.getConfiguration().getLong("mapred.max.split.size", |
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157 | Long.MAX_VALUE); |
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158 | } |
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159 | |
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160 | /** |
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161 | * Get a PathFilter instance of the filter set for the input paths. |
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162 | * |
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163 | * @return the PathFilter instance set for the job, NULL if none has been set. |
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164 | */ |
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165 | public static PathFilter getInputPathFilter(JobContext context) { |
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166 | Configuration conf = context.getConfiguration(); |
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167 | Class<?> filterClass = conf.getClass("mapred.input.pathFilter.class", null, |
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168 | PathFilter.class); |
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169 | return (filterClass != null) ? |
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170 | (PathFilter) ReflectionUtils.newInstance(filterClass, conf) : null; |
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171 | } |
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172 | |
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173 | /** List input directories. |
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174 | * Subclasses may override to, e.g., select only files matching a regular |
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175 | * expression. |
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176 | * |
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177 | * @param job the job to list input paths for |
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178 | * @return array of FileStatus objects |
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179 | * @throws IOException if zero items. |
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180 | */ |
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181 | protected List<FileStatus> listStatus(JobContext job |
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182 | ) throws IOException { |
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183 | List<FileStatus> result = new ArrayList<FileStatus>(); |
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184 | Path[] dirs = getInputPaths(job); |
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185 | if (dirs.length == 0) { |
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186 | throw new IOException("No input paths specified in job"); |
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187 | } |
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188 | |
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189 | List<IOException> errors = new ArrayList<IOException>(); |
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190 | |
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191 | // creates a MultiPathFilter with the hiddenFileFilter and the |
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192 | // user provided one (if any). |
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193 | List<PathFilter> filters = new ArrayList<PathFilter>(); |
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194 | filters.add(hiddenFileFilter); |
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195 | PathFilter jobFilter = getInputPathFilter(job); |
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196 | if (jobFilter != null) { |
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197 | filters.add(jobFilter); |
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198 | } |
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199 | PathFilter inputFilter = new MultiPathFilter(filters); |
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200 | |
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201 | for (int i=0; i < dirs.length; ++i) { |
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202 | Path p = dirs[i]; |
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203 | FileSystem fs = p.getFileSystem(job.getConfiguration()); |
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204 | FileStatus[] matches = fs.globStatus(p, inputFilter); |
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205 | if (matches == null) { |
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206 | errors.add(new IOException("Input path does not exist: " + p)); |
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207 | } else if (matches.length == 0) { |
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208 | errors.add(new IOException("Input Pattern " + p + " matches 0 files")); |
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209 | } else { |
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210 | for (FileStatus globStat: matches) { |
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211 | if (globStat.isDir()) { |
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212 | for(FileStatus stat: fs.listStatus(globStat.getPath(), |
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213 | inputFilter)) { |
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214 | result.add(stat); |
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215 | } |
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216 | } else { |
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217 | result.add(globStat); |
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218 | } |
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219 | } |
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220 | } |
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221 | } |
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222 | |
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223 | if (!errors.isEmpty()) { |
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224 | throw new InvalidInputException(errors); |
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225 | } |
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226 | LOG.info("Total input paths to process : " + result.size()); |
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227 | return result; |
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228 | } |
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229 | |
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230 | |
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231 | /** |
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232 | * Generate the list of files and make them into FileSplits. |
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233 | */ |
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234 | public List<InputSplit> getSplits(JobContext job |
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235 | ) throws IOException { |
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236 | long minSize = Math.max(getFormatMinSplitSize(), getMinSplitSize(job)); |
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237 | long maxSize = getMaxSplitSize(job); |
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238 | |
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239 | // generate splits |
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240 | List<InputSplit> splits = new ArrayList<InputSplit>(); |
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241 | for (FileStatus file: listStatus(job)) { |
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242 | Path path = file.getPath(); |
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243 | FileSystem fs = path.getFileSystem(job.getConfiguration()); |
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244 | long length = file.getLen(); |
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245 | BlockLocation[] blkLocations = fs.getFileBlockLocations(file, 0, length); |
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246 | if ((length != 0) && isSplitable(job, path)) { |
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247 | long blockSize = file.getBlockSize(); |
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248 | long splitSize = computeSplitSize(blockSize, minSize, maxSize); |
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249 | |
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250 | long bytesRemaining = length; |
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251 | while (((double) bytesRemaining)/splitSize > SPLIT_SLOP) { |
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252 | int blkIndex = getBlockIndex(blkLocations, length-bytesRemaining); |
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253 | splits.add(new FileSplit(path, length-bytesRemaining, splitSize, |
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254 | blkLocations[blkIndex].getHosts())); |
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255 | bytesRemaining -= splitSize; |
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256 | } |
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257 | |
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258 | if (bytesRemaining != 0) { |
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259 | splits.add(new FileSplit(path, length-bytesRemaining, bytesRemaining, |
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260 | blkLocations[blkLocations.length-1].getHosts())); |
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261 | } |
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262 | } else if (length != 0) { |
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263 | splits.add(new FileSplit(path, 0, length, blkLocations[0].getHosts())); |
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264 | } else { |
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265 | //Create empty hosts array for zero length files |
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266 | splits.add(new FileSplit(path, 0, length, new String[0])); |
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267 | } |
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268 | } |
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269 | LOG.debug("Total # of splits: " + splits.size()); |
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270 | return splits; |
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271 | } |
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272 | |
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273 | protected long computeSplitSize(long blockSize, long minSize, |
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274 | long maxSize) { |
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275 | return Math.max(minSize, Math.min(maxSize, blockSize)); |
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276 | } |
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277 | |
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278 | protected int getBlockIndex(BlockLocation[] blkLocations, |
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279 | long offset) { |
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280 | for (int i = 0 ; i < blkLocations.length; i++) { |
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281 | // is the offset inside this block? |
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282 | if ((blkLocations[i].getOffset() <= offset) && |
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283 | (offset < blkLocations[i].getOffset() + blkLocations[i].getLength())){ |
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284 | return i; |
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285 | } |
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286 | } |
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287 | BlockLocation last = blkLocations[blkLocations.length -1]; |
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288 | long fileLength = last.getOffset() + last.getLength() -1; |
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289 | throw new IllegalArgumentException("Offset " + offset + |
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290 | " is outside of file (0.." + |
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291 | fileLength + ")"); |
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292 | } |
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293 | |
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294 | /** |
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295 | * Sets the given comma separated paths as the list of inputs |
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296 | * for the map-reduce job. |
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297 | * |
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298 | * @param job the job |
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299 | * @param commaSeparatedPaths Comma separated paths to be set as |
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300 | * the list of inputs for the map-reduce job. |
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301 | */ |
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302 | public static void setInputPaths(Job job, |
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303 | String commaSeparatedPaths |
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304 | ) throws IOException { |
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305 | setInputPaths(job, StringUtils.stringToPath( |
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306 | getPathStrings(commaSeparatedPaths))); |
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307 | } |
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308 | |
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309 | /** |
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310 | * Add the given comma separated paths to the list of inputs for |
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311 | * the map-reduce job. |
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312 | * |
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313 | * @param job The job to modify |
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314 | * @param commaSeparatedPaths Comma separated paths to be added to |
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315 | * the list of inputs for the map-reduce job. |
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316 | */ |
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317 | public static void addInputPaths(Job job, |
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318 | String commaSeparatedPaths |
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319 | ) throws IOException { |
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320 | for (String str : getPathStrings(commaSeparatedPaths)) { |
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321 | addInputPath(job, new Path(str)); |
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322 | } |
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323 | } |
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324 | |
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325 | /** |
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326 | * Set the array of {@link Path}s as the list of inputs |
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327 | * for the map-reduce job. |
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328 | * |
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329 | * @param job The job to modify |
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330 | * @param inputPaths the {@link Path}s of the input directories/files |
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331 | * for the map-reduce job. |
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332 | */ |
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333 | public static void setInputPaths(Job job, |
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334 | Path... inputPaths) throws IOException { |
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335 | Configuration conf = job.getConfiguration(); |
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336 | FileSystem fs = FileSystem.get(conf); |
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337 | Path path = inputPaths[0].makeQualified(fs); |
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338 | StringBuffer str = new StringBuffer(StringUtils.escapeString(path.toString())); |
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339 | for(int i = 1; i < inputPaths.length;i++) { |
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340 | str.append(StringUtils.COMMA_STR); |
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341 | path = inputPaths[i].makeQualified(fs); |
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342 | str.append(StringUtils.escapeString(path.toString())); |
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343 | } |
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344 | conf.set("mapred.input.dir", str.toString()); |
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345 | } |
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346 | |
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347 | /** |
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348 | * Add a {@link Path} to the list of inputs for the map-reduce job. |
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349 | * |
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350 | * @param job The {@link Job} to modify |
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351 | * @param path {@link Path} to be added to the list of inputs for |
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352 | * the map-reduce job. |
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353 | */ |
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354 | public static void addInputPath(Job job, |
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355 | Path path) throws IOException { |
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356 | Configuration conf = job.getConfiguration(); |
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357 | FileSystem fs = FileSystem.get(conf); |
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358 | path = path.makeQualified(fs); |
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359 | String dirStr = StringUtils.escapeString(path.toString()); |
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360 | String dirs = conf.get("mapred.input.dir"); |
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361 | conf.set("mapred.input.dir", dirs == null ? dirStr : dirs + "," + dirStr); |
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362 | } |
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363 | |
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364 | // This method escapes commas in the glob pattern of the given paths. |
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365 | private static String[] getPathStrings(String commaSeparatedPaths) { |
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366 | int length = commaSeparatedPaths.length(); |
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367 | int curlyOpen = 0; |
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368 | int pathStart = 0; |
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369 | boolean globPattern = false; |
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370 | List<String> pathStrings = new ArrayList<String>(); |
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371 | |
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372 | for (int i=0; i<length; i++) { |
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373 | char ch = commaSeparatedPaths.charAt(i); |
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374 | switch(ch) { |
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375 | case '{' : { |
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376 | curlyOpen++; |
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377 | if (!globPattern) { |
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378 | globPattern = true; |
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379 | } |
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380 | break; |
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381 | } |
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382 | case '}' : { |
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383 | curlyOpen--; |
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384 | if (curlyOpen == 0 && globPattern) { |
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385 | globPattern = false; |
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386 | } |
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387 | break; |
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388 | } |
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389 | case ',' : { |
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390 | if (!globPattern) { |
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391 | pathStrings.add(commaSeparatedPaths.substring(pathStart, i)); |
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392 | pathStart = i + 1 ; |
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393 | } |
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394 | break; |
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395 | } |
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396 | } |
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397 | } |
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398 | pathStrings.add(commaSeparatedPaths.substring(pathStart, length)); |
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399 | |
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400 | return pathStrings.toArray(new String[0]); |
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401 | } |
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402 | |
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403 | /** |
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404 | * Get the list of input {@link Path}s for the map-reduce job. |
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405 | * |
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406 | * @param context The job |
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407 | * @return the list of input {@link Path}s for the map-reduce job. |
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408 | */ |
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409 | public static Path[] getInputPaths(JobContext context) { |
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410 | String dirs = context.getConfiguration().get("mapred.input.dir", ""); |
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411 | String [] list = StringUtils.split(dirs); |
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412 | Path[] result = new Path[list.length]; |
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413 | for (int i = 0; i < list.length; i++) { |
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414 | result[i] = new Path(StringUtils.unEscapeString(list[i])); |
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415 | } |
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416 | return result; |
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417 | } |
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418 | |
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419 | } |
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