com.toddbodnar.simpleHive.subQueries.colStats.java Source code

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Here is the source code for com.toddbodnar.simpleHive.subQueries.colStats.java

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package com.toddbodnar.simpleHive.subQueries;

import java.util.LinkedList;
import com.toddbodnar.simpleHive.IO.ramFile;
import com.toddbodnar.simpleHadoop.simpleContext;
import com.toddbodnar.simpleHive.helpers.controlCharacterConverter;
import com.toddbodnar.simpleHive.metastore.table;
import java.io.IOException;
import org.apache.hadoop.conf.Configuration;
import org.apache.hadoop.io.DoubleWritable;
import org.apache.hadoop.io.IntWritable;
import org.apache.hadoop.io.NullWritable;
import org.apache.hadoop.io.Text;
import org.apache.hadoop.mapreduce.Mapper;
import org.apache.hadoop.mapreduce.Reducer;

/**
 *
 * @author toddbodnar
 */
public class colStats extends query<DoubleWritable, Text> {

    public colStats(int statsCol) {
        this(statsCol, -1);
    }

    /**
     * Constructs a stats job for column statsCol, optimally grouped by groupBy
     *
     * @param statsCol
     * @param groupBy
     */
    public colStats(int statsCol, int groupBy) {
        groupByCol = groupBy;
        this.statsCol = statsCol;

    }

    private int groupByCol, statsCol;
    private static String stats[] = new String[] { "group", "max", "min", "avg", "sum", "count" };

    @Override
    public table getOutput() {
        if (super.getOutput() != null) {
            return super.getOutput();
        }
        table result = new table(new ramFile(), stats);
        result.setSeperator("\001");
        super.setOutput(result);
        return result;
    }

    @Override
    public Mapper getMapper() {
        return new ColStatsMapper();
    }

    private static class ColStatsMapper extends Mapper<Object, Text, Text, DoubleWritable> {
        private String separator;

        public void setup(Context cont) {
            separator = controlCharacterConverter
                    .convertFromReadable(cont.getConfiguration().get("SIMPLE_HIVE.COLSTATS.INPUT_SEPERATOR"));
        }

        public void map(Object key, Text line, Mapper.Context cont) throws IOException, InterruptedException {

            String row[] = line.toString().split(separator);
            String groupKey = "*";
            if (cont.getConfiguration().getInt("SIMPLE_HIVE.COLSTATS.GROUPBY", -1) != -1) {
                groupKey = row[cont.getConfiguration().getInt("SIMPLE_HIVE.COLSTATS.GROUPBY", -1)].toString();
            }

            cont.write(new Text(groupKey), new DoubleWritable(
                    Double.parseDouble(row[cont.getConfiguration().getInt("SIMPLE_HIVE.COLSTATS.COLUMN", -1)])));
        }
    }

    @Override
    public Reducer getReducer() {

        return new ColStatsReducer();

    }

    private static class ColStatsReducer extends Reducer<Text, DoubleWritable, Text, NullWritable> {

        public void reduce(Text key, Iterable<DoubleWritable> values, Context cont)
                throws IOException, InterruptedException {
            double min = Double.MAX_VALUE;
            double max = Double.MIN_VALUE;
            double sum = 0;
            int ct = 0;

            for (DoubleWritable value : values) {
                double number = value.get();
                if (min > number) {
                    min = number;
                }
                if (max < number) {
                    max = number;
                }
                sum += number;
                ct++;
            }

            double avg = sum / ct * 1.0;

            String result = key + "\001" + max + "\001" + min + "\001" + avg + "\001" + sum + "\001" + ct;
            cont.write(new Text(result), NullWritable.get());
        }
    }

    public String toString() {
        if (getInput() == null)
            return "Column Statistics on " + statsCol + " grouped by " + groupByCol;
        else
            return "Column Statistics on " + getInput().getColName(statsCol) + " grouped by "
                    + (groupByCol == -1 ? "Nothing" : getInput().getColName(groupByCol));
    }

    @Override
    public Class getKeyType() {
        return Text.class;
    }

    @Override
    public Class getValueType() {
        return DoubleWritable.class;
    }

    @Override
    public void writeConfig(Configuration conf) {
        conf.setInt("SIMPLE_HIVE.COLSTATS.COLUMN", statsCol);
        conf.setInt("SIMPLE_HIVE.COLSTATS.GROUPBY", groupByCol);
        conf.set("SIMPLE_HIVE.COLSTATS.INPUT_SEPERATOR",
                controlCharacterConverter.convertToReadable(getInput().getSeperator()));
    }
}