content: /*
   * Copyright (C) 2020 ActiveJ 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.activej.dataflow.dataset.impl;
  
  import io.activej.common.annotation.ExposedInternals;
  import io.activej.dataflow.dataset.Dataset;
  import io.activej.dataflow.dataset.LocallySortedDataset;
  import io.activej.dataflow.graph.DataflowContext;
  import io.activej.dataflow.graph.DataflowGraph;
  import io.activej.dataflow.graph.StreamId;
  import io.activej.dataflow.graph.StreamSchema;
  import io.activej.dataflow.node.impl.ReduceSimple;
  import io.activej.datastream.processor.reducer.Reducer;
  
  import java.util.ArrayList;
  import java.util.Collection;
  import java.util.List;
  import java.util.function.Function;
  
  @ExposedInternals
  public final class LocalSortReduce<K, I, O> extends LocallySortedDataset<K, O> {
  	public final LocallySortedDataset<K, I> input;
  	public final Reducer<K, I, O, ?> reducer;
  
  	public LocalSortReduce(
  		LocallySortedDataset<K, I> input, Reducer<K, I, O, ?> reducer, StreamSchema<O> resultStreamSchema,
  		Function<O, K> resultKeyFunction
  	) {
  		super(resultStreamSchema, input.keyComparator(), input.keyType(), resultKeyFunction);
  		this.input = input;
  		this.reducer = reducer;
  	}
  
  	@SuppressWarnings("unchecked")
  	@Override
  	public List<StreamId> channels(DataflowContext context) {
  		DataflowGraph graph = context.getGraph();
  		List<StreamId> outputStreamIds = new ArrayList<>();
  		int index = context.generateNodeIndex();
  		for (StreamId streamId : input.channels(context)) {
  			ReduceSimple<K, I, O, Object>.Builder nodeBuilder = ReduceSimple.builder(index, input.keyFunction(),
  				input.keyComparator(), (Reducer<K, I, O, Object>) reducer);
  			nodeBuilder.withInput(streamId);
  			ReduceSimple<K, I, O, Object> node = nodeBuilder.build();
  			graph.addNode(graph.getPartition(streamId), node);
  			outputStreamIds.add(node.output);
  		}
  		return outputStreamIds;
  	}
  
  	@Override
  	public Collection<Dataset<?>> getBases() {
  		return List.of(input);
  	}
  }
  