package test.invertedIndex

import java.io.IOException;
import java.util.Iterator;
import org.apache.hadoop.io.Text;
import org.apache.hadoop.mapred.OutputCollector;
import org.apache.hadoop.mapred.MapReduceBase;
import org.apache.hadoop.mapred.Reducer;
import org.apache.hadoop.mapred.Reporter;

import scala.collection.JavaConversions._

class invertedReducer() extends MapReduceBase
        with Reducer[Text, Text, Text, Text] {

    val valuesList = new StringBuffer();

    val finalValue = new Text();

    def reduce(key : Text,
        values: Iterator[Text],
        output: OutputCollector[Text, Text] ,
        reporter: Reporter) {

    // clear the value list
        valuesList.delete(0, valuesList.length());

        values.foreach ( v => valuesList.append(v.toString + ",") )

        finalValue.set(valuesList.substring(0, valuesList.length()-1).toString());
        output.collect(key, finalValue);

    }
}