com.twitter.heron.streamlet.impl.groupings.ReduceByKeyAndWindowCustomGrouping Maven / Gradle / Ivy

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//  Copyright 2017 Twitter. All rights reserved.
//
//  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 com.twitter.heron.streamlet.impl.groupings;

import java.util.ArrayList;
import java.util.List;

import com.twitter.heron.api.grouping.CustomStreamGrouping;
import com.twitter.heron.api.topology.TopologyContext;
import com.twitter.heron.streamlet.SerializableFunction;

/**
 * ReduceByKeyAndWindowCustomGrouping is the class that routes the incoming tuples
 * into the ReduceByKeyAndWindowOperator. It essentially ensures that the values being
 * routed are of type KeyValue uses the key to route the tuple to the destination.
 * The current implementation is identical to JoinCustomGrouping but it might
 * evolve in the future.
 */
public class ReduceByKeyAndWindowCustomGrouping implements CustomStreamGrouping {
  private static final long serialVersionUID = -7630948017550637716L;
  private SerializableFunction keyExtractor;
  private List taskIds;

  public ReduceByKeyAndWindowCustomGrouping(SerializableFunction keyExtractor) {
    this.keyExtractor = keyExtractor;
  }

  @Override
  public void prepare(TopologyContext context, String component,
                      String streamId, List targetTasks) {
    this.taskIds = targetTasks;
  }

  @SuppressWarnings("unchecked")
  @Override
  public List chooseTasks(List