/***********************************************************************************************************************
*
* Copyright (C) 2010-2013 by the Stratosphere project (http://stratosphere.eu)
*
* Licensed 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 eu.stratosphere.api.java.operators.translation;
import java.util.Iterator;
import eu.stratosphere.api.common.functions.GenericCombine;
import eu.stratosphere.api.common.functions.GenericGroupReduce;
import eu.stratosphere.api.common.operators.UnaryOperatorInformation;
import eu.stratosphere.api.common.operators.base.GroupReduceOperatorBase;
import eu.stratosphere.api.java.functions.GroupReduceFunction;
import eu.stratosphere.api.java.functions.GroupReduceFunction.Combinable;
import eu.stratosphere.api.java.operators.Keys;
import eu.stratosphere.api.java.tuple.Tuple2;
import eu.stratosphere.types.TypeInformation;
import eu.stratosphere.util.Collector;
/**
* A reduce operator that takes 2-tuples (key-value pairs), and applies the group reduce operation only
* on the unwrapped values.
*/
public class PlanUnwrappingReduceGroupOperator<IN, OUT, K> extends GroupReduceOperatorBase<Tuple2<K, IN>, OUT, GenericGroupReduce<Tuple2<K, IN>,OUT>> {
public PlanUnwrappingReduceGroupOperator(GroupReduceFunction<IN, OUT> udf, Keys.SelectorFunctionKeys<IN, K> key, String name,
TypeInformation<OUT> outType, TypeInformation<Tuple2<K, IN>> typeInfoWithKey, boolean combinable)
{
super(combinable ? new TupleUnwrappingCombinableGroupReducer<IN, OUT, K>(udf) : new TupleUnwrappingNonCombinableGroupReducer<IN, OUT, K>(udf),
new UnaryOperatorInformation<Tuple2<K, IN>, OUT>(typeInfoWithKey, outType), key.computeLogicalKeyPositions(), name);
super.setCombinable(combinable);
}
// --------------------------------------------------------------------------------------------
@Combinable
public static final class TupleUnwrappingCombinableGroupReducer<IN, OUT, K> extends WrappingFunction<GroupReduceFunction<IN, OUT>>
implements GenericGroupReduce<Tuple2<K, IN>, OUT>, GenericCombine<Tuple2<K, IN>>
{
private static final long serialVersionUID = 1L;
private TupleUnwrappingIterator<IN, K> iter;
private TupleWrappingCollector<IN, K> coll;
private TupleUnwrappingCombinableGroupReducer(GroupReduceFunction<IN, OUT> wrapped) {
super(wrapped);
this.iter = new TupleUnwrappingIterator<IN, K>();
this.coll = new TupleWrappingCollector<IN, K>(this.iter);
}
@Override
public void reduce(Iterator<Tuple2<K, IN>> values, Collector<OUT> out) throws Exception {
iter.set(values);
this.wrappedFunction.reduce(iter, out);
}
@Override
public void combine(Iterator<Tuple2<K, IN>> values, Collector<Tuple2<K, IN>> out) throws Exception {
iter.set(values);
coll.set(out);
this.wrappedFunction.combine(iter, coll);
}
@Override
public String toString() {
return this.wrappedFunction.toString();
}
}
public static final class TupleUnwrappingNonCombinableGroupReducer<IN, OUT, K> extends WrappingFunction<GroupReduceFunction<IN, OUT>>
implements GenericGroupReduce<Tuple2<K, IN>, OUT>
{
private static final long serialVersionUID = 1L;
private final TupleUnwrappingIterator<IN, K> iter;
private TupleUnwrappingNonCombinableGroupReducer(GroupReduceFunction<IN, OUT> wrapped) {
super(wrapped);
this.iter = new TupleUnwrappingIterator<IN, K>();
}
@Override
public void reduce(Iterator<Tuple2<K, IN>> values, Collector<OUT> out) throws Exception {
iter.set(values);
this.wrappedFunction.reduce(iter, out);
}
@Override
public String toString() {
return this.wrappedFunction.toString();
}
}
}