/*
* Copyright (C) 2015 SoftIndex LLC.
*
* 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 io.datakernel.datagraph.node;
import com.google.common.base.Function;
import io.datakernel.datagraph.graph.StreamId;
import io.datakernel.datagraph.graph.TaskContext;
import io.datakernel.stream.processor.StreamReducerSimple;
import io.datakernel.stream.processor.StreamReducers;
import java.util.*;
import static java.util.Collections.singletonList;
/**
* Represents a simple reducer node, with a single key function and reducer for all internalConsumers.
*
* @param <K> keys type
* @param <I> input data type
* @param <O> output data type
* @param <A> accumulator type
*/
public final class NodeReduceSimple<K, I, O, A> implements Node {
private final Function<I, K> keyFunction;
private final Comparator<K> keyComparator;
private final StreamReducers.Reducer<K, I, O, A> reducer;
private final List<StreamId> inputs = new ArrayList<>();
private final StreamId output = new StreamId();
public NodeReduceSimple(Function<I, K> keyFunction, Comparator<K> keyComparator,
StreamReducers.Reducer<K, I, O, A> reducer) {
this.keyFunction = keyFunction;
this.keyComparator = keyComparator;
this.reducer = reducer;
}
public void addInput(StreamId input) {
inputs.add(input);
}
public StreamId getOutput() {
return output;
}
@Override
public Collection<StreamId> getOutputs() {
return singletonList(output);
}
@Override
public void createAndBind(TaskContext taskContext) {
StreamReducerSimple<K, I, O, A> streamReducerSimple =
StreamReducerSimple.create(taskContext.getEventloop(), keyFunction, keyComparator, reducer);
for (StreamId input : inputs) {
taskContext.bindChannel(input, streamReducerSimple.newInput());
}
taskContext.export(output, streamReducerSimple.getOutput());
}
}