text: /**
   *
   * 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.bookkeeper.bookie.storage.ldb;
  
  import static org.junit.Assert.assertEquals;
  import static org.junit.Assert.assertNull;
  
  import io.netty.buffer.ByteBuf;
  import io.netty.buffer.Unpooled;
  import io.netty.buffer.UnpooledByteBufAllocator;
  
  import org.junit.Test;
  
  /**
   * Unit test for {@link ReadCache}.
   */
  public class ReadCacheTest {
  
      @Test
      public void simple() {
          ReadCache cache = new ReadCache(UnpooledByteBufAllocator.DEFAULT, 10 * 1024);
  
          assertEquals(0, cache.count());
          assertEquals(0, cache.size());
  
          ByteBuf entry = Unpooled.wrappedBuffer(new byte[1024]);
          cache.put(1, 0, entry);
  
          assertEquals(1, cache.count());
          assertEquals(1024, cache.size());
  
          assertEquals(entry, cache.get(1, 0));
          assertNull(cache.get(1, 1));
  
          for (int i = 1; i < 10; i++) {
              cache.put(1, i, entry);
          }
  
          assertEquals(10, cache.count());
          assertEquals(10 * 1024, cache.size());
  
          cache.put(1, 10, entry);
  
          // First half of entries will have been evicted
          for (int i = 0; i < 5; i++) {
              assertNull(cache.get(1, i));
          }
  
          for (int i = 5; i < 11; i++) {
              assertEquals(entry, cache.get(1, i));
          }
  
          cache.close();
      }
  
      @Test
      public void emptyCache() {
          ReadCache cache = new ReadCache(UnpooledByteBufAllocator.DEFAULT, 10 * 1024);
  
          assertEquals(0, cache.count());
          assertEquals(0, cache.size());
          assertEquals(null, cache.get(0, 0));
  
          cache.close();
      }
  
      @Test
      public void multipleSegments() {
          // Test with multiple smaller segments
          ReadCache cache = new ReadCache(UnpooledByteBufAllocator.DEFAULT, 10 * 1024, 2 * 1024);
  
          assertEquals(0, cache.count());
          assertEquals(0, cache.size());
  
          for (int i = 0; i < 10; i++) {
              ByteBuf entry = Unpooled.wrappedBuffer(new byte[1024]);
              entry.setInt(0, i);
              cache.put(1, i, entry);
          }
  
          for (int i = 0; i < 10; i++) {
              ByteBuf res = cache.get(1, i);
              assertEquals(1, res.refCnt());
  
              assertEquals(1024, res.readableBytes());
              assertEquals(i, res.getInt(0));
          }
  
          assertEquals(10, cache.count());
          assertEquals(10 * 1024, cache.size());
  
          // Putting one more entry, should trigger the 1st segment rollover
          ByteBuf entry = Unpooled.wrappedBuffer(new byte[1024]);
          cache.put(2, 0, entry);
  
          assertEquals(9, cache.count());
          assertEquals(9 * 1024, cache.size());
  
          cache.close();
      }
  }
  