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IWorkerHook.java
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IWorkerHook.java
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/**
* 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.hooks;
import java.io.Serializable;
import java.util.Map;
import org.apache.storm.task.WorkerTopologyContext;
import org.apache.storm.task.WorkerUserContext;
/**
* An IWorkerHook represents a topology component that can be executed when a worker starts, and when a worker shuts down. It can be useful
* when you want to execute operations before topology processing starts, or cleanup operations before your workers shut down.
*/
public interface IWorkerHook extends Serializable {
/**
* This method is called when a worker is started.
*
* @param topoConf The Storm configuration for this worker
* @param context This object can be used to get information about this worker's place within the topology
*
* @deprecated see {@link IWorkerHook#start(Map, WorkerUserContext)}
*/
default void start(Map<String, Object> topoConf, WorkerTopologyContext context) {
// NOOP
}
/**
* This method is called when a worker is started and can be used to do necessary prep-processing and allow initialization of shared
* application state.
*
* @param topoConf The Storm configuration for this worker
* @param context This object can be used to get information about this worker's place within the topology and exposes
* {@link WorkerUserContext#setResource(String, Object)} to set the shared application state.
*/
default void start(Map<String, Object> topoConf, WorkerUserContext context) {
start(topoConf, context);
}
/**
* This method is called right before a worker shuts down.
*/
void shutdown();
}