package com.ontology2.bakemono.bloom;
import org.apache.hadoop.conf.Configuration;
import org.apache.hadoop.io.NullWritable;
import org.apache.hadoop.io.Text;
import org.apache.hadoop.io.Writable;
import org.apache.hadoop.mapreduce.Reducer;
import org.apache.hadoop.util.bloom.BloomFilter;
import org.apache.hadoop.util.bloom.Key;
import org.apache.hadoop.util.hash.Hash;
import java.io.IOException;
import java.util.Arrays;
public class BloomReducer extends Reducer<Text,Writable,NullWritable,BloomFilter> {
BloomFilter f;
static final public String THIS="com.ontology2.bakemono.bloom.BloomReducer";
static final public String VECTOR_SIZE=THIS+".vectorSize";
static final public String NB_HASH=THIS+".nbHash";
static final public String HASH_TYPE=THIS+".hashType";
@Override
protected void setup(Context context) throws IOException, InterruptedException {
super.setup(context);
Configuration c=context.getConfiguration();
int vectorSize=c.getInt(VECTOR_SIZE,0);
int nbHash=c.getInt(NB_HASH,0);
String hashType=c.get(HASH_TYPE, "murmur");
f=new BloomFilter(vectorSize,nbHash, Hash.parseHashType(hashType));
}
@Override
protected void reduce(Text key, Iterable<Writable> values, Context context) throws IOException, InterruptedException {
f.add(toKey(key));
}
@Override
protected void cleanup(Context context) throws IOException, InterruptedException {
context.write(NullWritable.get(),f);
}
public static Key toKey(Text t) {
return new Key(Arrays.copyOfRange(t.getBytes(), 0, t.getLength()));
}
public static Key toKey(String s) {
return toKey(new Text(s));
}
}