| /** |
| * 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.grouping; |
| |
| import java.io.Serializable; |
| import java.util.List; |
| import org.apache.storm.generated.GlobalStreamId; |
| import org.apache.storm.task.WorkerTopologyContext; |
| |
| public interface CustomStreamGrouping extends Serializable { |
| |
| /** |
| * Tells the stream grouping at runtime the tasks in the target bolt. This information should be used in chooseTasks to determine the |
| * target tasks. |
| * |
| * <p>It also tells the grouping the metadata on the stream this grouping will be used on. |
| */ |
| void prepare(WorkerTopologyContext context, GlobalStreamId stream, List<Integer> targetTasks); |
| |
| /** |
| * This function implements a custom stream grouping. It takes in as input the number of tasks in the target bolt in prepare and returns |
| * the tasks to send the tuples to. |
| * |
| * @param values the values to group on |
| */ |
| List<Integer> chooseTasks(int taskId, List<Object> values); |
| } |