| /** |
| * 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.operation; |
| |
| import java.io.Serializable; |
| import java.util.Map; |
| |
| /** |
| * Parent interface for Trident `Filter`s and `Function`s. |
| * |
| * `Operation` defines two lifecycle methods for Trident components. The `prepare()` method is called once when the `Operation` is first |
| * initialized. The `cleanup()` method is called in local mode when the local cluster is being shut down. In distributed mode, the |
| * `cleanup()` method is not guaranteed to be called in every situation, but Storm will make a best effort call `cleanup()` whenever |
| * possible. |
| */ |
| public interface Operation extends Serializable { |
| /** |
| * Called when the `Operation` is first initialized. |
| * |
| * @param conf the Storm configuration map |
| * @param context the operation context which provides information such as the number of partitions in the stream, and the current |
| * partition index. It also provides methods for registering operation-specific metrics. |
| * @see org.apache.storm.trident.operation.TridentOperationContext |
| */ |
| void prepare(Map<String, Object> conf, TridentOperationContext context); |
| |
| /** |
| * When running in local mode, called when the local cluster is being shut down. |
| */ |
| void cleanup(); |
| } |