/*
* 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.flink.api.java.operators.translation;
import org.apache.flink.annotation.Internal;
import org.apache.flink.api.common.functions.GroupCombineFunction;
import org.apache.flink.api.common.functions.GroupReduceFunction;
import org.apache.flink.api.common.operators.UnaryOperatorInformation;
import org.apache.flink.api.common.operators.base.GroupReduceOperatorBase;
import org.apache.flink.api.common.typeinfo.TypeInformation;
import org.apache.flink.api.common.operators.Keys;
import org.apache.flink.api.java.tuple.Tuple2;
import org.apache.flink.util.Collector;
/**
* A reduce operator that takes 2-tuples (key-value pairs), and applies the group reduce operation only
* on the unwrapped values.
*/
@Internal
public class PlanUnwrappingReduceGroupOperator<IN, OUT, K> extends GroupReduceOperatorBase<Tuple2<K, IN>, OUT, GroupReduceFunction<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 TupleUnwrappingGroupCombinableGroupReducer<IN, OUT, K>(udf) :
new TupleUnwrappingNonCombinableGroupReducer<IN, OUT, K>(udf),
new UnaryOperatorInformation<>(typeInfoWithKey, outType), key.computeLogicalKeyPositions(), name);
super.setCombinable(combinable);
}
// --------------------------------------------------------------------------------------------
public static final class TupleUnwrappingGroupCombinableGroupReducer<IN, OUT, K> extends WrappingFunction<GroupReduceFunction<IN, OUT>>
implements GroupReduceFunction<Tuple2<K, IN>, OUT>, GroupCombineFunction<Tuple2<K, IN>, Tuple2<K, IN>>
{
private static final long serialVersionUID = 1L;
private TupleUnwrappingIterator<IN, K> iter;
private TupleWrappingCollector<IN, K> coll;
private TupleUnwrappingGroupCombinableGroupReducer(GroupReduceFunction<IN, OUT> wrapped) {
super(wrapped);
if(!GroupCombineFunction.class.isAssignableFrom(wrappedFunction.getClass())) {
throw new IllegalArgumentException("Wrapped reduce function does not implement the GroupCombineFunction interface.");
}
this.iter = new TupleUnwrappingIterator<>();
this.coll = new TupleWrappingCollector<>(this.iter);
}
@Override
public void reduce(Iterable<Tuple2<K, IN>> values, Collector<OUT> out) throws Exception {
iter.set(values.iterator());
this.wrappedFunction.reduce(iter, out);
}
@SuppressWarnings("unchecked")
@Override
public void combine(Iterable<Tuple2<K, IN>> values, Collector<Tuple2<K, IN>> out) throws Exception {
iter.set(values.iterator());
coll.set(out);
((GroupCombineFunction<IN, IN>)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 GroupReduceFunction<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<>();
}
@Override
public void reduce(Iterable<Tuple2<K, IN>> values, Collector<OUT> out) throws Exception {
iter.set(values.iterator());
this.wrappedFunction.reduce(iter, out);
}
@Override
public String toString() {
return this.wrappedFunction.toString();
}
}
}