content: package com.manning.hip.ch12.crunch;
  
  import com.cloudera.crunch.*;
  import com.cloudera.crunch.impl.mr.MRPipeline;
  import org.apache.hadoop.conf.Configuration;
  import org.apache.hadoop.fs.Path;
  
  import java.io.IOException;
  
  public class InvertedIndex {
    public static void main(String[] args) throws IOException {
      Configuration conf = new Configuration();
      Path output = new Path(args[1]);
      output.getFileSystem(conf).delete(output, true);
  
      // Create an object to coordinate pipeline creation and execution.
      Pipeline pipeline = new MRPipeline(InvertedIndex.class, conf);
  
      // Reference a given text file as a collection of Strings.
      PCollection<String> lines = pipeline.readTextFile(args[0]);
  
      // Define a function that splits each line in a PCollection of Strings into a
      // PCollection made up of the individual words in the file.
      PTable<String, String> wordDocs = CrunchUtils.extractWordFileTable(lines);
  
      PTable<String, String> result = CrunchUtils.uniqueValues(wordDocs);
  
      // Instruct the pipeline to write the resulting counts to a text file.
      pipeline.writeTextFile(result, args[1]);
      // Execute the pipeline as a MapReduce.
      pipeline.done();
    }
  }
  