TemporalAggregator.java

package org.chombo.mr;

import java.io.IOException;

import org.apache.hadoop.conf.Configuration;
import org.apache.hadoop.conf.Configured;
import org.apache.hadoop.fs.Path;
import org.apache.hadoop.io.LongWritable;
import org.apache.hadoop.io.NullWritable;
import org.apache.hadoop.io.Text;
import org.apache.hadoop.mapreduce.Job;
import org.apache.hadoop.mapreduce.Mapper;
import org.apache.hadoop.mapreduce.Reducer;
import org.apache.hadoop.mapreduce.lib.input.FileInputFormat;
import org.apache.hadoop.mapreduce.lib.output.FileOutputFormat;
import org.apache.hadoop.util.Tool;
import org.apache.hadoop.util.ToolRunner;
import org.chombo.util.Tuple;
import org.chombo.util.Utility;

public class TemporalAggregator  extends Configured implements Tool {
	private static String configDelim = ",";
    private static final String AGGR_COUNT = "count";
    private static final String AGGR_SUM = "sum";

	@Override
	public int run(String[] args) throws Exception {
        Job job = new Job(getConf());
        String jobName = "Seasonal aggregator  for numerical attributes";
        job.setJobName(jobName);
        
        job.setJarByClass(TemporalAggregator.class);

        FileInputFormat.addInputPath(job, new Path(args[0]));
        FileOutputFormat.setOutputPath(job, new Path(args[1]));

        Utility.setConfiguration(job.getConfiguration(), "chombo");
        job.setMapperClass(TemporalAggregator.AggregatorMapper.class);
        job.setReducerClass(TemporalAggregator.AggregateReducer.class);
        job.setCombinerClass(TemporalAggregator.AggregateCombiner.class);
        
        job.setMapOutputKeyClass(Tuple.class);
        job.setMapOutputValueClass(Tuple.class);

        job.setOutputKeyClass(NullWritable.class);
        job.setOutputValueClass(Text.class);

        int numReducer = job.getConfiguration().getInt("tag.num.reducer", -1);
        numReducer = -1 == numReducer ? job.getConfiguration().getInt("num.reducer", 1) : numReducer;
        job.setNumReduceTasks(numReducer);

        int status =  job.waitForCompletion(true) ? 0 : 1;
        return status;
	}

	/**
	 * @author pranab
	 *
	 */
	public static class AggregatorMapper extends Mapper<LongWritable, Text, Tuple, Tuple> {
		private Tuple outKey = new Tuple();
		private Tuple outVal = new Tuple();
		private int[]  attributes;
        private String fieldDelimRegex;
        private String[] items;
        private int[] idOrdinals;
        private int timeStampFieldOrdinal;
        private static long secInHour = 60L * 60;
        private long cycleIndex;
        private long timeStamp;
        private String aggregatorType;
        private long timeZoneShift;
        private long cycleLengthSec;
        
        protected void setup(Context context) throws IOException, InterruptedException {
        	Configuration config = context.getConfiguration();
        	fieldDelimRegex = config.get("field.delim.regex", ",");
        	attributes = Utility.intArrayFromString(config.get("tag.quant.attr.list"),fieldDelimRegex );
        	idOrdinals = Utility.intArrayFromString(config.get("tag.id.field.ordinals"), configDelim);
        	timeStampFieldOrdinal = config.getInt("tag.time.stamp.field.ordinal", -1);
        	cycleLengthSec = (long)(Double.parseDouble(config.get("tag.seasonal.cycle.length.hour")) *  secInHour);
        	aggregatorType = config.get("tag.aggregator.type");
        	int  timeZoneHours = config.getInt("tag.time.zone.hours",  0);
        	timeZoneShift = timeZoneHours * secInHour;
       }
		
        @Override
        protected void map(LongWritable key, Text value, Context context)
            throws IOException, InterruptedException {
            items  =  value.toString().split(fieldDelimRegex, -1);
            timeStamp = Long.parseLong(items[timeStampFieldOrdinal]);
            cycleIndex = (timeStamp  + timeZoneShift) / cycleLengthSec;
            
        	for (int attr : attributes) {
            	outKey.initialize();
            	outVal.initialize();
            	if (null != idOrdinals) {
            		outKey.addFromArray(items, idOrdinals);
            	}
            	outKey.add( cycleIndex, attr);
            	
            	if (aggregatorType.equals(AGGR_COUNT)) {
            		outVal.add(1);
            	} else if (aggregatorType.equals(AGGR_SUM)) {
            		outVal.add(Double.parseDouble(items[attr]));
            	} else {
        			throw new IllegalArgumentException("invalid aggregation function");
        		}
            	context.write(outKey, outVal);
        	}
        }
	}
	
	/**
	 * @author pranab
	 *
	 */
	public static class AggregateCombiner extends Reducer<Tuple, Tuple, Tuple, Tuple> {
		private Tuple outVal = new Tuple();
		private int totalCount;
		private double sum;
		private String aggregatorType;

        /* (non-Javadoc)
         * @see org.apache.hadoop.mapreduce.Reducer#setup(org.apache.hadoop.mapreduce.Reducer.Context)
         */
        protected void setup(Context context) throws IOException, InterruptedException {
        	Configuration config = context.getConfiguration();
        	aggregatorType = config.get("tag.aggregator.type");
        }
        
        /* (non-Javadoc)
         * @see org.apache.hadoop.mapreduce.Reducer#reduce(KEYIN, java.lang.Iterable, org.apache.hadoop.mapreduce.Reducer.Context)
         */
        protected void reduce(Tuple  key, Iterable<Tuple> values, Context context)
        		throws IOException, InterruptedException {
    		sum = 0;
    		totalCount = 0;
    		for (Tuple val : values) {
            	if (aggregatorType.equals(AGGR_COUNT)) {
            		totalCount += val.getInt(0);
            	} else {
            		sum  += val.getDouble(0);
            	}
    		}
        
    		outVal.initialize();
    		if (aggregatorType.equals(AGGR_COUNT)) {
    			outVal.add(totalCount);
    		} else if (aggregatorType.equals(AGGR_SUM)) {
    			outVal.add(sum);
    		} 
        	context.write(key, outVal);       	
        }
	}
	
	   /**
	    * @author pranab
	    *
	    */
	public static class  AggregateReducer extends Reducer<Tuple, Tuple, NullWritable, Text> {
		protected Text outVal = new Text();
		protected String fieldDelim;
		protected double sum;
		protected int totalCount;
		private String aggregatorType;
		
		protected void setup(Context context) throws IOException, InterruptedException {
			Configuration config = context.getConfiguration();
			fieldDelim = config.get("field.delim.out", ",");
        	aggregatorType = config.get("tag.aggregator.type");
		}

		protected void reduce(Tuple  key, Iterable<Tuple> values, Context context)
     		throws IOException, InterruptedException {
 			sum = 0;
 			totalCount = 0;
 			for (Tuple val : values) {
         		if (aggregatorType.equals(AGGR_COUNT)) {
         			totalCount += val.getInt(0);
         		}	else if (aggregatorType.equals(AGGR_SUM)) {
         			sum  += val.getDouble(0);
         		}
 			}
 		
     		if (aggregatorType.equals(AGGR_COUNT)) {
     			outVal.set(key.toString() + fieldDelim   + totalCount);
     		} else if (aggregatorType.equals(AGGR_SUM)) {
     			outVal.set(key.toString() +fieldDelim +  sum);
     		} 
     	
     		context.write(NullWritable.get(), outVal);
     	}		
	}

	/**
	 * @param args
	 */
	public static void main(String[] args) throws Exception {
		int exitCode = ToolRunner.run(new SeasonalDetector(), args);
		System.exit(exitCode);
	}
	
}