| /** |
| * 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.storm.trident.partition; |
| |
| import java.util.ArrayList; |
| import java.util.Arrays; |
| import java.util.Collections; |
| import java.util.HashMap; |
| import java.util.List; |
| import java.util.Map; |
| import org.apache.storm.generated.GlobalStreamId; |
| import org.apache.storm.grouping.CustomStreamGrouping; |
| import org.apache.storm.task.WorkerTopologyContext; |
| |
| |
| public class IdentityGrouping implements CustomStreamGrouping { |
| final Map<Integer, List<Integer>> precomputed = new HashMap<>(); |
| |
| @Override |
| public void prepare(WorkerTopologyContext context, GlobalStreamId stream, List<Integer> tasks) { |
| List<Integer> sourceTasks = new ArrayList<>(context.getComponentTasks(stream.get_componentId())); |
| Collections.sort(sourceTasks); |
| if (sourceTasks.size() != tasks.size()) { |
| throw new RuntimeException("Can only do an identity grouping when source and target have same number of tasks"); |
| } |
| tasks = new ArrayList<>(tasks); |
| Collections.sort(tasks); |
| for (int i = 0; i < sourceTasks.size(); i++) { |
| int s = sourceTasks.get(i); |
| int t = tasks.get(i); |
| precomputed.put(s, Arrays.asList(t)); |
| } |
| } |
| |
| @Override |
| public List<Integer> chooseTasks(int task, List<Object> values) { |
| List<Integer> ret = precomputed.get(task); |
| if (ret == null) { |
| throw new RuntimeException("Tuple emitted by task that's not part of this component. Should be impossible"); |
| } |
| return ret; |
| } |
| |
| } |