ruanhang1993 commented on a change in pull request #17556: URL: https://github.com/apache/flink/pull/17556#discussion_r747224765
########## File path: flink-test-utils-parent/flink-test-utils-junit/src/main/java/org/apache/flink/testutils/junit/SharedObjectsExtension.java ########## @@ -0,0 +1,178 @@ +/* + * 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.testutils.junit; + +import org.junit.jupiter.api.extension.AfterEachCallback; +import org.junit.jupiter.api.extension.BeforeEachCallback; +import org.junit.jupiter.api.extension.ExtensionContext; + +import java.util.Map; +import java.util.Objects; +import java.util.concurrent.ConcurrentHashMap; +import java.util.concurrent.atomic.AtomicInteger; + +/** + * This rule allows objects to be used both in the main test case as well as in UDFs by using + * serializable {@link SharedReference}s. Usage: + * + * <pre><code> + * {@literal @RegisterExtension} + * public final SharedObjectsExtension sharedObjects = SharedObjectsExtension.create(); + * + * {@literal @Test} + * public void test() throws Exception { + * StreamExecutionEnvironment env = StreamExecutionEnvironment.getExecutionEnvironment(); + * {@literal SharedReference<Queue<Long>> listRef = sharedObjects.add(new ConcurrentLinkedQueue<>());} + * int n = 10000; + * env.setParallelism(100); + * env.fromSequence(0, n).map(i -> listRef.get().add(i)); + * env.execute(); + * assertEquals(n + 1, listRef.get().size()); + * assertEquals( + * LongStream.rangeClosed(0, n).boxed().collect(Collectors.toList()), + * listRef.get().stream().sorted().collect(Collectors.toList())); + * } + * </code></pre> + * + * <p>The main idea is that shared objects are bound to the scope of a test case instead of a class. + * That allows us to: + * + * <ul> + * <li>Avoid all kinds of static fields in test classes that only exist since all fields in UDFs + * need to be serializable. + * <li>Hopefully make it easier to reason about the test setup + * <li>Facilitate to share more test building blocks across test classes. + * <li>Fully allow tests to be rerun/run in parallel without worrying about static fields + * </ul> + * + * <p>Note that since the shared objects are accessed through multiple threads, they need to be + * thread-safe or accessed in a thread-safe manner. + */ +public class SharedObjectsExtension implements BeforeEachCallback, AfterEachCallback { Review comment: OK, I will add the annotation. -- 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: issues-unsubscr...@flink.apache.org For queries about this service, please contact Infrastructure at: us...@infra.apache.org
