/*
    *    Copyright 2009-2023 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
    *
    *       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.ibatis.cache;
  
  import static org.junit.jupiter.api.Assertions.assertEquals;
  import static org.junit.jupiter.api.Assertions.assertNotNull;
  import static org.junit.jupiter.api.Assertions.assertNull;
  
  import java.lang.reflect.Field;
  import java.util.Map;
  
  import org.apache.ibatis.cache.decorators.LruCache;
  import org.apache.ibatis.cache.impl.PerpetualCache;
  import org.junit.jupiter.api.Test;
  
  class LruCacheTest {
  
    @Test
    void shouldRemoveLeastRecentlyUsedItemInBeyondFiveEntries() {
      LruCache cache = new LruCache(new PerpetualCache("default"));
      cache.setSize(5);
      for (int i = 0; i < 5; i++) {
        cache.putObject(i, i);
      }
      assertEquals(0, cache.getObject(0));
      cache.putObject(5, 5);
      assertNull(cache.getObject(1));
      assertEquals(5, cache.getSize());
    }
  
    @Test
    void shouldRemoveItemOnDemand() {
      Cache cache = new LruCache(new PerpetualCache("default"));
      cache.putObject(0, 0);
      assertNotNull(cache.getObject(0));
      cache.removeObject(0);
      assertNull(cache.getObject(0));
    }
  
    @Test
    void shouldFlushAllItemsOnDemand() {
      Cache cache = new LruCache(new PerpetualCache("default"));
      for (int i = 0; i < 5; i++) {
        cache.putObject(i, i);
      }
      assertNotNull(cache.getObject(0));
      assertNotNull(cache.getObject(4));
      cache.clear();
      assertNull(cache.getObject(0));
      assertNull(cache.getObject(4));
    }
  
    @Test
    void shouldCacheSizeEqualsKeyMapSize() throws Exception {
      LruCache cache = new LruCache(new PerpetualCache("default"));
      cache.setSize(5);
      for (int i = 0; i < 5; i++) {
        cache.putObject(i, i);
      }
      cache.removeObject(1);
      Field keyMap = cache.getClass().getDeclaredField("keyMap");
      keyMap.setAccessible(true);
      Map<Object, Object> map = (Map<Object, Object>) keyMap.get(cache);
      assertEquals(map.size(), cache.getSize());
    }
  
  }