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1   /*
2    * Licensed to the Apache Software Foundation (ASF) under one or more
3    * contributor license agreements.  See the NOTICE file distributed with
4    * this work for additional information regarding copyright ownership.
5    * The ASF licenses this file to You under the Apache License, Version 2.0
6    * (the "License"); you may not use this file except in compliance with
7    * the License.  You may obtain a copy of the License at
8    *
9    *      https://www.apache.org/licenses/LICENSE-2.0
10   *
11   * Unless required by applicable law or agreed to in writing, software
12   * distributed under the License is distributed on an "AS IS" BASIS,
13   * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
14   * See the License for the specific language governing permissions and
15   * limitations under the License.
16   */
17  package org.apache.commons.lang3.concurrent;
18  
19  import static org.junit.jupiter.api.Assertions.assertNull;
20  
21  import java.util.concurrent.atomic.AtomicBoolean;
22  
23  import org.junit.jupiter.api.Test;
24  
25  /**
26   * Test class for {@code AtomicInitializer}.
27   */
28  class AtomicInitializerObjectTest extends AbstractConcurrentInitializerTest<Object> {
29  
30      /**
31       * Returns the initializer to be tested.
32       *
33       * @return the {@code AtomicInitializer}
34       */
35      @Override
36      protected ConcurrentInitializer<Object> createInitializer() {
37          return new AtomicInitializer<Object>() {
38              @Override
39              protected Object initialize() {
40                  return new Object();
41              }
42          };
43      }
44  
45      @Test
46      void testGetThatReturnsNullFirstTime() throws ConcurrentException {
47          final AtomicInitializer<Object> initializer = new AtomicInitializer<Object>() {
48              final AtomicBoolean firstRun = new AtomicBoolean(true);
49  
50              @Override
51              protected Object initialize() {
52                  if (firstRun.getAndSet(false)) {
53                      return null;
54                  }
55                  return new Object();
56              }
57          };
58  
59          assertNull(initializer.get());
60          assertNull(initializer.get());
61      }
62  }