| /* |
| * 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.flink.runtime.leaderretrieval; |
| |
| import javax.annotation.Nullable; |
| |
| import java.util.UUID; |
| |
| /** |
| * Classes which want to be notified about a changing leader by the {@link LeaderRetrievalService} |
| * have to implement this interface. |
| */ |
| public interface LeaderRetrievalListener { |
| |
| /** |
| * This method is called by the {@link LeaderRetrievalService} when a new leader is elected. |
| * |
| * <p>If both arguments are null then it signals that leadership was revoked without a new |
| * leader having been elected. |
| * |
| * @param leaderAddress The address of the new leader |
| * @param leaderSessionID The new leader session ID |
| */ |
| void notifyLeaderAddress(@Nullable String leaderAddress, @Nullable UUID leaderSessionID); |
| |
| /** |
| * This method is called by the {@link LeaderRetrievalService} in case of an exception. This |
| * assures that the {@link LeaderRetrievalListener} is aware of any problems occurring in the |
| * {@link LeaderRetrievalService} thread. |
| * |
| * @param exception |
| */ |
| void handleError(Exception exception); |
| } |