1 /*

     2  * Copyright (c) 2015, 2018, Oracle and/or its affiliates. All rights reserved.

     3  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.

     4  *

     5  * This code is free software; you can redistribute it and/or modify it

     6  * under the terms of the GNU General Public License version 2 only, as

     7  * published by the Free Software Foundation.  Oracle designates this

     8  * particular file as subject to the "Classpath" exception as provided

     9  * by Oracle in the LICENSE file that accompanied this code.

    10  *

    11  * This code is distributed in the hope that it will be useful, but WITHOUT

    12  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or

    13  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License

    14  * version 2 for more details (a copy is included in the LICENSE file that

    15  * accompanied this code).

    16  *

    17  * You should have received a copy of the GNU General Public License version

    18  * 2 along with this work; if not, write to the Free Software Foundation,

    19  * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.

    20  *

    21  * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA

    22  * or visit www.oracle.com if you need additional information or have any

    23  * questions.

    24  */

    25 package jdk.internal.net.http.common;

    26 

    27 import java.nio.ByteBuffer;

    28 import java.util.concurrent.ConcurrentLinkedQueue;

    29 

    30 /**

    31  * The class provides reuse of ByteBuffers.

    32  * It is supposed that all requested buffers have the same size for a long period of time.

    33  * That is why there is no any logic splitting buffers into different buckets (by size). It's unnecessary.

    34  *

    35  * At the same moment it is allowed to change requested buffers size (all smaller buffers will be discarded).

    36  * It may be needed for example, if after rehandshaking netPacketBufferSize was changed.

    37  */

    38 public class ByteBufferPool {

    39 

    40     private final java.util.Queue<ByteBuffer> pool = new ConcurrentLinkedQueue<>();

    41 

    42     public ByteBufferPool() {

    43     }

    44 

    45     public ByteBufferReference get(int size) {

    46         ByteBuffer buffer;

    47         while ((buffer = pool.poll()) != null) {

    48             if (buffer.capacity() >= size) {

    49                 return ByteBufferReference.of(buffer, this);

    50             }

    51         }

    52         return ByteBufferReference.of(ByteBuffer.allocate(size), this);

    53     }

    54 

    55     public void release(ByteBuffer buffer) {

    56         buffer.clear();

    57         pool.offer(buffer);

    58     }

    59 

    60 }