mcvsubbu commented on a change in pull request #3604: Add ControllerLeadershipManager as single place to check controller leadership changes URL: https://github.com/apache/incubator-pinot/pull/3604#discussion_r240711320
########## File path: pinot-controller/src/main/java/com/linkedin/pinot/controller/ControllerLeadershipManager.java ########## @@ -0,0 +1,116 @@ +/** + * Copyright (C) 2014-2018 LinkedIn Corp. ([email protected]) + * + * Licensed 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 com.linkedin.pinot.controller; + +import java.util.Map; +import java.util.concurrent.ConcurrentHashMap; +import org.apache.helix.HelixManager; +import org.apache.helix.api.listeners.ControllerChangeListener; +import org.slf4j.Logger; +import org.slf4j.LoggerFactory; + + +/** + * Single place for listening on controller changes + * This should be created at controller startup and everyone who wants to listen to controller changes should subscribe + */ +public class ControllerLeadershipManager { + + private static final Logger LOGGER = LoggerFactory.getLogger(ControllerLeadershipManager.class); + + private static ControllerLeadershipManager INSTANCE = null; + + private HelixManager _helixManager; + private volatile boolean _amILeader = false; + + private Map<String, ControllerChangeSubscriber> _subscribers = new ConcurrentHashMap<>(); + + private ControllerLeadershipManager(HelixManager helixManager) { + _helixManager = helixManager; + _helixManager.addControllerListener((ControllerChangeListener) notificationContext -> onControllerChange()); + } + + /** + * Create an instance of ControllerLeadershipManager + * @param helixManager + */ + public static synchronized void createInstance(HelixManager helixManager) { Review comment: I thought about that as well. I think the option is between create() and init(HelixManager). Perhaps the latter is a bit less confusing. ---------------------------------------------------------------- This is an automated message from the Apache Git Service. To respond to the message, please log on GitHub and use the URL above to go to the specific comment. For queries about this service, please contact Infrastructure at: [email protected] With regards, Apache Git Services --------------------------------------------------------------------- To unsubscribe, e-mail: [email protected] For additional commands, e-mail: [email protected]
