| /** |
| * 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.topology; |
| |
| import org.apache.storm.state.State; |
| |
| /** |
| * <p> |
| * Common methods for stateful components in the topology. |
| * </p> |
| * A stateful component is one that has state (e.g. the result of some computation in a bolt) and wants the framework to manage its state. |
| */ |
| public interface IStatefulComponent<T extends State> extends IComponent { |
| /** |
| * This method is invoked by the framework with the previously saved state of the component. This is invoked after prepare but before |
| * the component starts processing tuples. |
| * |
| * @param state the previously saved state of the component. |
| */ |
| void initState(T state); |
| |
| /** |
| * This is a hook for the component to perform some actions just before the framework commits its state. |
| */ |
| void preCommit(long txid); |
| |
| /** |
| * This is a hook for the component to perform some actions just before the framework prepares its state. |
| */ |
| void prePrepare(long txid); |
| |
| /** |
| * This is a hook for the component to perform some actions just before the framework rolls back the prepared state. |
| */ |
| void preRollback(); |
| } |