/*
    *    Copyright 2009-2022 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.assertNotNull;
  import static org.junit.jupiter.api.Assertions.assertNull;
  import static org.junit.jupiter.api.Assertions.assertTrue;
  
  import org.apache.ibatis.cache.decorators.SerializedCache;
  import org.apache.ibatis.cache.decorators.WeakCache;
  import org.apache.ibatis.cache.impl.PerpetualCache;
  import org.junit.jupiter.api.Test;
  
  class WeakCacheTest {
  
    @Test
    void shouldDemonstrateObjectsBeingCollectedAsNeeded() {
      final int N = 3000000;
      WeakCache cache = new WeakCache(new PerpetualCache("default"));
      for (int i = 0; i < N; i++) {
        cache.putObject(i, i);
        if (cache.getSize() < i + 1) {
          // System.out.println("Cache exceeded with " + (i + 1) + " entries.");
          break;
        }
        if ((i + 1) % 100000 == 0) {
          // Try performing GC.
          System.gc();
        }
      }
      assertTrue(cache.getSize() < N);
    }
  
    @Test
    void shouldDemonstrateCopiesAreEqual() {
      Cache cache = new WeakCache(new PerpetualCache("default"));
      cache = new SerializedCache(cache);
      for (int i = 0; i < 1000; i++) {
        cache.putObject(i, i);
        Object value = cache.getObject(i);
        assertTrue(value == null || value.equals(i));
      }
    }
  
    @Test
    void shouldRemoveItemOnDemand() {
      WeakCache cache = new WeakCache(new PerpetualCache("default"));
      cache.putObject(0, 0);
      assertNotNull(cache.getObject(0));
      cache.removeObject(0);
      assertNull(cache.getObject(0));
    }
  
    @Test
    void shouldFlushAllItemsOnDemand() {
      WeakCache cache = new WeakCache(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));
    }
  
  }