content: /*
   *
   * 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.directentrylogger;
  
  import io.netty.buffer.ByteBufAllocator;
  import java.io.IOException;
  import java.util.concurrent.ArrayBlockingQueue;
  import org.apache.bookkeeper.common.util.nativeio.NativeIO;
  
  /**
   * BufferPool used to manage Buffers.
   */
  public class BufferPool implements AutoCloseable {
      private final ArrayBlockingQueue<Buffer> pool;
  
      BufferPool(NativeIO nativeIO, ByteBufAllocator allocator, int bufferSize, int maxPoolSize) throws IOException {
          pool = new ArrayBlockingQueue<>(maxPoolSize);
          for (int i = 0; i < maxPoolSize; i++) {
              pool.add(new Buffer(nativeIO, allocator, bufferSize));
          }
      }
  
      Buffer acquire() throws IOException {
          try {
              return pool.take();
          } catch (InterruptedException ie) {
              Thread.currentThread().interrupt();
              throw new IOException(ie);
          }
      }
  
      void release(Buffer buffer) {
          buffer.reset();
          if (!pool.add(buffer)) {
              buffer.free();
          }
      }
  
      @Override
      public void close() {
          while (true) {
              Buffer b = pool.poll();
              if (b == null) {
                  break;
              }
  
              b.free();
          }
      }
  }
  