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POhadoop inverted-index without recurrence of file names
 

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    <p>what i have in output is:</p> <p>word , file ----- ------ wordx Doc2, Doc1, Doc1, Doc1, Doc1, Doc1, Doc1, Doc1</p> <p>what i want is:</p> <p>word , file ----- ------ wordx Doc2, Doc1</p> <pre><code>public static class LineIndexMapper extends MapReduceBase implements Mapper&lt;LongWritable, Text, Text, Text&gt; { private final static Text word = new Text(); private final static Text location = new Text(); public void map(LongWritable key, Text val, OutputCollector&lt;Text, Text&gt; output, Reporter reporter) throws IOException { FileSplit fileSplit = (FileSplit) reporter.getInputSplit(); String fileName = fileSplit.getPath().getName(); location.set(fileName); String line = val.toString(); StringTokenizer itr = new StringTokenizer(line.toLowerCase()); while (itr.hasMoreTokens()) { word.set(itr.nextToken()); output.collect(word, location); } } } public static class LineIndexReducer extends MapReduceBase implements Reducer&lt;Text, Text, Text, Text&gt; { public void reduce(Text key, Iterator&lt;Text&gt; values, OutputCollector&lt;Text, Text&gt; output, Reporter reporter) throws IOException { boolean first = true; StringBuilder toReturn = new StringBuilder(); while (values.hasNext()) { if (!first) { toReturn.append(", "); } first = false; toReturn.append(values.next().toString()); } output.collect(key, new Text(toReturn.toString())); } } </code></pre> <p>for the best performance - where should i skip the recurring file name? map,reduce or both? ps: i am a beginner in writing MR tasks and also trying to figure out programming logic with my question.</p>
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