/*
    * 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.commons.lang3.concurrent;
  
  import static org.junit.jupiter.api.Assertions.assertEquals;
  import static org.junit.jupiter.api.Assertions.assertNull;
  
  import java.util.concurrent.atomic.AtomicBoolean;
  import java.util.concurrent.atomic.AtomicInteger;
  
  import org.apache.commons.lang3.function.FailableConsumer;
  import org.apache.commons.lang3.function.FailableSupplier;
  import org.junit.jupiter.api.BeforeEach;
  import org.junit.jupiter.api.Test;
  
  /**
   * Test class for {@code AtomicSafeInitializer} which also serves as a simple example.
   */
  public class AtomicSafeInitializerSupplierTest extends AbstractConcurrentInitializerCloseAndExceptionsTest {
  
      /** An initCounter used in testing. Reset before each test */
      private AtomicInteger initCounter = new AtomicInteger();
  
      /**
       * Creates the initializer to be tested.
       *
       * @return the {@code AtomicSafeInitializer} under test
       */
      @Override
      protected ConcurrentInitializer<Object> createInitializer() {
          return AtomicSafeInitializer.<Object>builder().setInitializer(this::incAndMakeObject).get();
      }
  
      @Override
      protected ConcurrentInitializer<CloseableObject> createInitializerThatThrowsException(
              final FailableSupplier<CloseableObject, ? extends Exception> supplier,
              final FailableConsumer<CloseableObject, ? extends Exception> closer) {
          return AtomicSafeInitializer.<CloseableObject>builder().setInitializer(supplier).setCloser(closer).get();
      }
  
      /** A supplier method used in testing */
      private Object incAndMakeObject() {
          initCounter.incrementAndGet();
          return new Object();
      }
  
      @BeforeEach
      public void setUp() {
          initCounter = new AtomicInteger();
      }
  
      @Test
      public void testGetThatReturnsNullFirstTime() throws ConcurrentException {
          final AtomicSafeInitializer<Object> initializer = new AtomicSafeInitializer<Object>() {
              final AtomicBoolean firstRun = new AtomicBoolean(true);
  
              @Override
              protected Object initialize() {
                  if (firstRun.getAndSet(false)) {
                      return null;
                  } else {
                      return new Object();
                  }
              }
          };
  
          assertNull(initializer.get());
          assertNull(initializer.get());
      }
  
      /**
       * Tests that initialize() is called only once.
       *
       * @throws org.apache.commons.lang3.concurrent.ConcurrentException because {@link #testGetConcurrent()} may throw it
       * @throws InterruptedException because {@link #testGetConcurrent()} may throw it
       */
      @Test
      public void testNumberOfInitializeInvocations() throws ConcurrentException, InterruptedException {
          testGetConcurrent();
          assertEquals(1, initCounter.get(), "Wrong number of invocations");
      }
  }