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ASF GitHub Bot commented on FLINK-3544: --------------------------------------- Github user tillrohrmann commented on a diff in the pull request: https://github.com/apache/flink/pull/1741#discussion_r56376080 --- Diff: flink-runtime/src/main/java/org/apache/flink/runtime/clusterframework/messages/StopClusterSuccessful.java --- @@ -0,0 +1,48 @@ +/* + * 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.clusterframework.messages; + +import org.apache.flink.runtime.messages.RequiresLeaderSessionID; + +/** + * Generic message to signal the cluster listener that the cluster has been shut down. + */ +public class StopClusterSuccessful implements RequiresLeaderSessionID, java.io.Serializable { + + private static final long serialVersionUID = 42L; + + private static StopClusterSuccessful INSTANCE; + + /** + * Private constructor. Initial singleton in get() method. + */ + private StopClusterSuccessful() {} + + public static StopClusterSuccessful get() { + if (INSTANCE == null) { + INSTANCE = new StopClusterSuccessful(); --- End diff -- Concurrency issue here: Multiple threads might create more than one singleton here. > ResourceManager runtime components > ---------------------------------- > > Key: FLINK-3544 > URL: https://issues.apache.org/jira/browse/FLINK-3544 > Project: Flink > Issue Type: Sub-task > Components: ResourceManager > Affects Versions: 1.1.0 > Reporter: Maximilian Michels > Assignee: Maximilian Michels > Fix For: 1.1.0 > > -- This message was sent by Atlassian JIRA (v6.3.4#6332)