content: // Protocol Buffers - Google's data interchange format
  // Copyright 2008 Google Inc.  All rights reserved.
  // https://developers.google.com/protocol-buffers/
  //
  // Redistribution and use in source and binary forms, with or without
  // modification, are permitted provided that the following conditions are
  // met:
  //
  //     * Redistributions of source code must retain the above copyright
  // notice, this list of conditions and the following disclaimer.
  //     * Redistributions in binary form must reproduce the above
  // copyright notice, this list of conditions and the following disclaimer
  // in the documentation and/or other materials provided with the
  // distribution.
  //     * Neither the name of Google Inc. nor the names of its
  // contributors may be used to endorse or promote products derived from
  // this software without specific prior written permission.
  //
  // THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
  // "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
  // LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
  // A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
  // OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
  // SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
  // LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
  // DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
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  // OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  
  package com.google.protobuf;
  
  import java.nio.ByteBuffer;
  
  /**
   * An object responsible for allocation of buffers. This is an extension point to enable buffer
   * pooling within an application.
   */
  @ExperimentalApi
  abstract class BufferAllocator {
    private static final BufferAllocator UNPOOLED =
        new BufferAllocator() {
          @Override
          public AllocatedBuffer allocateHeapBuffer(int capacity) {
            return AllocatedBuffer.wrap(new byte[capacity]);
          }
  
          @Override
          public AllocatedBuffer allocateDirectBuffer(int capacity) {
            return AllocatedBuffer.wrap(ByteBuffer.allocateDirect(capacity));
          }
        };
  
    /** Returns an unpooled buffer allocator, which will create a new buffer for each request. */
    public static BufferAllocator unpooled() {
      return UNPOOLED;
    }
  
    /** Allocates a buffer with the given capacity that is backed by an array on the heap. */
    public abstract AllocatedBuffer allocateHeapBuffer(int capacity);
  
    /** Allocates a direct (i.e. non-heap) buffer with the given capacity. */
    public abstract AllocatedBuffer allocateDirectBuffer(int capacity);
  }
  