Joscorbe commented on code in PR #295: URL: https://github.com/apache/jackrabbit-oak/pull/295#discussion_r963535775
########## oak-store-document/src/main/java/org/apache/jackrabbit/oak/plugins/document/mongo/MongoClusterListener.java: ########## @@ -0,0 +1,82 @@ +/* + * 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.jackrabbit.oak.plugins.document.mongo; + +import com.mongodb.ServerAddress; +import com.mongodb.connection.ServerConnectionState; +import com.mongodb.connection.ServerDescription; +import com.mongodb.event.ClusterDescriptionChangedEvent; +import com.mongodb.event.ClusterListener; +import org.jetbrains.annotations.Nullable; + +import java.util.concurrent.CountDownLatch; +import java.util.concurrent.TimeUnit; + +public class MongoClusterListener implements ClusterListener { + + // Sometimes we need to wait a few seconds in case the connection was just created, the listener + // didn't have time to receive the description from the cluster. This latch is used to check + // if the connection was properly initialized. + private final CountDownLatch LATCH; + private final int LATCH_AWAIT_TIMEOUT = 15; + private boolean replicaSet = false; + private ServerAddress serverAddress; + private ServerAddress primaryAddress; + + public MongoClusterListener() { + LATCH = new CountDownLatch(1); + } + + @Nullable + public ServerAddress getServerAddress() { + waitForLatch(); Review Comment: The idea behind the Latch mechanism is to wait a few seconds until a new connection is fully established. This only happens when the connection is really fresh. After the first `clusterDescriptionChanged` is called, the variables are filled in and the latch is no longer used. If the latch times out, the ServerAddress returned will be null, which shouldn't be a problem as it has the `Nullable` annotation and when it's used it is checked for null. For example: https://github.com/apache/jackrabbit-oak/blob/c6ddcc55bee3de915459af01e91edad32d538f3d/oak-store-document/src/test/java/org/apache/jackrabbit/oak/plugins/document/mongo/MongoStatusTest.java#L207-L211 -- This is an automated message from the Apache Git Service. To respond to the message, please log on to GitHub and use the URL above to go to the specific comment. To unsubscribe, e-mail: dev-unsubscr...@jackrabbit.apache.org For queries about this service, please contact Infrastructure at: us...@infra.apache.org
