| /** |
| * 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 org.apache.avro.mapred; |
| |
| import java.io.IOException; |
| import java.util.Iterator; |
| |
| import org.apache.hadoop.mapred.JobConf; |
| import org.apache.hadoop.mapred.MapReduceBase; |
| import org.apache.hadoop.mapred.OutputCollector; |
| import org.apache.hadoop.mapred.Reporter; |
| import org.apache.hadoop.mapred.Reducer; |
| |
| abstract class HadoopReducerBase<K,V,OUT,KO,VO> extends MapReduceBase |
| implements Reducer<AvroKey<K>, AvroValue<V>, KO, VO> { |
| |
| private AvroReducer<K,V,OUT> reducer; |
| private AvroCollector<OUT> collector; |
| |
| protected abstract AvroReducer<K,V,OUT> getReducer(JobConf conf); |
| protected abstract AvroCollector<OUT> getCollector(OutputCollector<KO,VO> c); |
| |
| @Override |
| public void configure(JobConf conf) { |
| this.reducer = getReducer(conf); |
| } |
| |
| class ReduceIterable implements Iterable<V>, Iterator<V> { |
| private Iterator<AvroValue<V>> values; |
| public boolean hasNext() { return values.hasNext(); } |
| public V next() { return values.next().datum(); } |
| public void remove() { throw new UnsupportedOperationException(); } |
| public Iterator<V> iterator() { return this; } |
| } |
| private ReduceIterable reduceIterable = new ReduceIterable(); |
| |
| @Override |
| public final void reduce(AvroKey<K> key, Iterator<AvroValue<V>> values, |
| OutputCollector<KO, VO> out, |
| Reporter reporter) throws IOException { |
| if (this.collector == null) |
| this.collector = getCollector(out); |
| reduceIterable.values = values; |
| reducer.reduce(key.datum(), reduceIterable, collector, reporter); |
| } |
| |
| @Override |
| public void close() throws IOException { |
| this.reducer.close(); |
| } |
| } |