/**
    *    Copyright 2009-2019 the original author or authors.
    *
    *    Licensed 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.ibatis.submitted.heavy_initial_load;
  
  import java.io.Reader;
  import java.util.ArrayList;
  import java.util.Collections;
  import java.util.List;
  
  import org.apache.ibatis.io.Resources;
  import org.apache.ibatis.session.SqlSession;
  import org.apache.ibatis.session.SqlSessionFactory;
  import org.apache.ibatis.session.SqlSessionFactoryBuilder;
  import org.junit.jupiter.api.Assertions;
  import org.junit.jupiter.api.BeforeAll;
  import org.junit.jupiter.api.Test;
  
  class HeavyInitialLoadTest {
  
    private static SqlSessionFactory sqlSessionFactory;
  
    @BeforeAll
    static void initSqlSessionFactory() throws Exception {
      try (Reader reader = Resources.getResourceAsReader("org/apache/ibatis/submitted/heavy_initial_load/ibatisConfig.xml")) {
        sqlSessionFactory = new SqlSessionFactoryBuilder().build(reader);
      }
  
      sqlSessionFactory.getConfiguration().getEnvironment().getDataSource().getConnection().close();
    }
  
    private static final int THREAD_COUNT = 5;
  
    /**
     * Test to demonstrate the effect of the
     * https://issues.apache.org/jira/browse/OGNL-121 issue in ognl on mybatis.
     *
     * Use the thing mapper for the first time in multiple threads. The mapper contains
     * a lot of ognl references to static final class members like:
     *
     * <code>@org.apache.ibatis.submitted.heavy_initial_load.Code@_1.equals(code)</code>
     *
     * Handling of these references is optimized in ognl (because they never change), but
     * version 2.6.9 has a bug in caching the result . As a result the reference is
     * translated to a 'null' value, which is used to invoke the 'equals' method on
     * (hence the 'target is null for method equals' exception).
     */
    @Test
    void selectThingsConcurrently_mybatis_issue_224() throws Exception {
      final List<Throwable> throwables = Collections.synchronizedList(new ArrayList<>());
  
      Thread[] threads = new Thread[THREAD_COUNT];
      for (int i = 0; i < THREAD_COUNT; i++) {
        threads[i] = new Thread(() -> {
          try {
            selectThing();
          } catch(Exception exception) {
            throwables.add(exception);
          }
        });
  
        threads[i].start();
      }
  
      for (int i = 0; i < THREAD_COUNT; i++) {
        threads[i].join();
      }
  
      Assertions.assertTrue(throwables.isEmpty(), "There were exceptions: " + throwables);
    }
  
    void selectThing() {
      try (SqlSession sqlSession = sqlSessionFactory.openSession()) {
        ThingMapper mapper = sqlSession.getMapper(ThingMapper.class);
        Thing selected = mapper.selectByCode(Code._1);
        Assertions.assertEquals(1, selected.getId().longValue());
      }
    }
  }