CustomStreamGroupingHelper.java

// Copyright 2016 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.common.utils.misc;

import java.util.ArrayList;
import java.util.HashMap;
import java.util.List;
import java.util.Map;

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

class CustomStreamGroupingHelper {
  // Mapping from steamid to a List of Targets
  private final Map<String, List<Target>> targets;

  CustomStreamGroupingHelper() {
    targets = new HashMap<>();
  }

  public void add(String streamId,
                  List<Integer> taskIds,
                  CustomStreamGrouping grouping,
                  String sourceComponentName) {
    if (!targets.containsKey(streamId)) {
      targets.put(streamId, new ArrayList<Target>());
    }
    targets.get(streamId).add(new Target(taskIds, grouping, sourceComponentName));
  }

  void prepare(TopologyContext context) {
    for (String streamId : targets.keySet()) {
      for (Target target : targets.get(streamId)) {
        target.prepare(context, streamId);
      }
    }
  }

  List<Integer> chooseTasks(String streamId, List<Object> values) {
    List<Target> targetList = targets.get(streamId);
    if (targetList != null) {
      List<Integer> res = new ArrayList<>();
      for (Target target : targetList) {
        res.addAll(target.chooseTasks(values));
      }

      return res;
    }
    return null;
  }

  boolean isCustomGroupingEmpty() {
    return targets.isEmpty();
  }

  private static class Target {
    private final String componentName;
    private final List<Integer> taskIds;
    private final CustomStreamGrouping grouping;

    Target(List<Integer> taskIds, CustomStreamGrouping grouping, String componentName) {
      this.taskIds = taskIds;
      this.grouping = grouping;
      this.componentName = componentName;
    }

    public String getComponentName() {
      return componentName;
    }

    public List<Integer> getTaskIds() {
      return taskIds;
    }

    public CustomStreamGrouping getGrouping() {
      return grouping;
    }

    public void prepare(TopologyContext context, String streamId) {
      grouping.prepare(context, componentName, streamId, taskIds);
    }

    private List<Integer> chooseTasks(List<Object> values) {
      return grouping.chooseTasks(values);
    }
  }
}