/*
* Licensed to the Apache Software Foundation (ASF) under one
* or more contributor license agreements. See the NOTICE file
* distributed with this work for additional information
* regarding copyright ownership. The ASF licenses this file
* to you under the Apache License, Version 2.0 (the
* "License"); you may not use this file except in compliance
* with the License. You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing,
* software distributed under the License is distributed on an
* "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
* KIND, either express or implied. See the License for the
* specific language governing permissions and limitations
* under the License.
*/
package fm.last.darling.mapred;
import java.io.IOException;
import java.util.Iterator;
import org.apache.hadoop.hbase.io.BatchUpdate;
import org.apache.hadoop.hbase.io.ImmutableBytesWritable;
import org.apache.hadoop.io.IntWritable;
import org.apache.hadoop.mapred.MapReduceBase;
import org.apache.hadoop.mapred.OutputCollector;
import org.apache.hadoop.mapred.Reducer;
import org.apache.hadoop.mapred.Reporter;
import fm.last.darling.hbase.HBaseUtils;
import fm.last.darling.io.records.NSpacePoint;
import fm.last.darling.nspace.Projection;
public class ZohmgReducer extends MapReduceBase implements
Reducer<NSpacePoint, IntWritable, ImmutableBytesWritable, BatchUpdate> {
public void reduce(NSpacePoint point, Iterator<IntWritable> values,
OutputCollector<ImmutableBytesWritable, BatchUpdate> output, Reporter reporter) throws IOException {
// sum the values.
int sum = 0;
while (values.hasNext())
sum += values.next().get();
byte[] n = Integer.valueOf(sum).toString().getBytes();
// or, if you'd rather like to store byte-y ints:
// byte[] n = Util.intToByteArray(sum);
// HBase stuff.
byte[] rowkey = HBaseUtils.formatRowkey(point.getUnit(), point.getTimestamp());
ImmutableBytesWritable rk = new ImmutableBytesWritable(rowkey);
BatchUpdate update = new BatchUpdate(rowkey);
Projection p = new Projection(point);
update.put(p.toHBaseCFQ(), n);
// dispatch to HBase.
output.collect(rk, update);
}
}