| /* |
| * 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.giraph.master; |
| |
| import java.io.DataInput; |
| import java.io.DataOutput; |
| import java.io.IOException; |
| |
| import org.apache.giraph.aggregators.Aggregator; |
| import org.apache.giraph.conf.GiraphConfigurationSettable; |
| import org.apache.giraph.conf.ImmutableClassesGiraphConfiguration; |
| import org.apache.giraph.reducers.ReduceSameTypeOperation; |
| import org.apache.giraph.utils.ReflectionUtils; |
| import org.apache.giraph.utils.WritableUtils; |
| import org.apache.hadoop.io.Writable; |
| |
| /** |
| * Translates aggregation operation to reduce operations. |
| * |
| * @param <A> Aggregation object type |
| */ |
| public class AggregatorReduceOperation<A extends Writable> |
| extends ReduceSameTypeOperation<A> implements GiraphConfigurationSettable { |
| /** Aggregator class */ |
| private Class<? extends Aggregator<A>> aggregatorClass; |
| /** Aggregator */ |
| private Aggregator<A> aggregator; |
| /** Configuration */ |
| private ImmutableClassesGiraphConfiguration<?, ?, ?> conf; |
| |
| /** Constructor */ |
| public AggregatorReduceOperation() { |
| } |
| |
| /** |
| * Constructor |
| * @param aggregatorClass Aggregator class |
| * @param conf Configuration |
| */ |
| public AggregatorReduceOperation( |
| Class<? extends Aggregator<A>> aggregatorClass, |
| ImmutableClassesGiraphConfiguration<?, ?, ?> conf) { |
| this.aggregatorClass = aggregatorClass; |
| this.conf = conf; |
| initAggregator(); |
| } |
| |
| /** Initialize aggregator */ |
| private void initAggregator() { |
| aggregator = ReflectionUtils.newInstance(aggregatorClass, conf); |
| aggregator.setAggregatedValue(null); |
| } |
| |
| @Override |
| public A createInitialValue() { |
| A agg = aggregator.createInitialValue(); |
| if (agg == null) { |
| throw new IllegalStateException( |
| "Aggregators initial value must not be null, but is for " + |
| aggregator); |
| } |
| return agg; |
| } |
| |
| /** |
| * Creates copy of this object |
| * @return copy |
| */ |
| public AggregatorReduceOperation<A> createCopy() { |
| return new AggregatorReduceOperation<>(aggregatorClass, conf); |
| } |
| |
| public Class<? extends Aggregator<A>> getAggregatorClass() { |
| return aggregatorClass; |
| } |
| |
| @Override |
| public synchronized A reduce(A curValue, A valueToReduce) { |
| aggregator.setAggregatedValue(curValue); |
| aggregator.aggregate(valueToReduce); |
| A aggregated = aggregator.getAggregatedValue(); |
| aggregator.setAggregatedValue(null); |
| return aggregated; |
| } |
| |
| @Override |
| public void setConf(ImmutableClassesGiraphConfiguration conf) { |
| this.conf = conf; |
| } |
| |
| @Override |
| public void write(DataOutput out) throws IOException { |
| WritableUtils.writeClass(aggregatorClass, out); |
| } |
| |
| @Override |
| public void readFields(DataInput in) throws IOException { |
| aggregatorClass = WritableUtils.readClass(in); |
| initAggregator(); |
| } |
| |
| |
| } |