/*
    * 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
    *
    *      https://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.builder;
  
  import java.util.LinkedList;
  import java.util.Random;
  
  import org.apache.commons.lang3.AbstractLangTest;
  import org.junit.jupiter.api.Disabled;
  import org.junit.jupiter.api.Test;
  
  /**
   * Tests concurrent access for {@link ReflectionToStringBuilder}.
   * <p>
   * The {@link ToStringStyle} class includes a registry to avoid infinite loops for objects with circular references. We
   * want to make sure that we do not get concurrency exceptions accessing this registry.
   * </p>
   *
   * @see <a href="https://issues.apache.org/jira/browse/LANG-762">[LANG-762] Handle or document ReflectionToStringBuilder
   *      and ToStringBuilder for collections that are not thread safe</a>
   */
  class ReflectionToStringBuilderMutateInspectConcurrencyTest extends AbstractLangTest {
  
      final class InspectingClient implements Runnable {
          private final TestFixture testFixture;
  
          InspectingClient(final TestFixture testFixture) {
              this.testFixture = testFixture;
          }
  
          @Override
          public void run() {
              ReflectionToStringBuilder.toString(testFixture);
          }
      }
  
      final class MutatingClient implements Runnable {
          private final TestFixture testFixture;
          private final Random random = new Random();
  
          MutatingClient(final TestFixture testFixture) {
              this.testFixture = testFixture;
          }
  
          @Override
          public void run() {
              if (random.nextBoolean()) {
                  testFixture.add();
              } else {
                  testFixture.delete();
              }
          }
      }
  
      final class TestFixture {
          private final LinkedList<Integer> listField = new LinkedList<>();
          private final Random random = new Random();
          private final int N = 100;
  
          TestFixture() {
              synchronized (this) {
                  for (int i = 0; i < N; i++) {
                      listField.add(Integer.valueOf(i));
                  }
              }
          }
  
          public synchronized void add() {
              listField.add(Integer.valueOf(random.nextInt(N)));
          }
  
          public synchronized void delete() {
              listField.remove(Integer.valueOf(random.nextInt(N)));
          }
      }
  
      @Test
      @Disabled
      void testConcurrency() {
          final TestFixture testFixture = new TestFixture();
          final int numMutators = 10;
          final int numIterations = 10;
          for (int i = 0; i < numIterations; i++) {
              for (int j = 0; j < numMutators; j++) {
                 final Thread t = new Thread(new MutatingClient(testFixture));
                 t.start();
                 final Thread s = new Thread(new InspectingClient(testFixture));
                 s.start();
             }
         }
     }
 }