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    1   /*
    2    * Copyright 2012 The Netty Project
    3    *
    4    * The Netty Project licenses this file to you under the Apache License,
    5    * version 2.0 (the "License"); you may not use this file except in compliance
    6    * with the License. You may obtain a copy of the License at:
    7    *
    8    *   http://www.apache.org/licenses/LICENSE-2.0
    9    *
    10   * Unless required by applicable law or agreed to in writing, software
    11   * distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
    12   * WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
    13   * License for the specific language governing permissions and limitations
    14   * under the License.
    15   */
    16  package org.jboss.netty.util.internal;
    17
    18  import java.lang.reflect.Method;
    19  import java.nio.ByteBuffer;
    20
    21  /**
    22   * This is fork of ElasticSearch's ByteBufferAllocator.Cleaner class
    23   */
    24  public final class ByteBufferUtil {
    25      private static final boolean CLEAN_SUPPORTED;
    26      private static final Method directBufferCleaner;
    27      private static final Method directBufferCleanerClean;
    28
    29      static {
    30          Method directBufferCleanerX = null;
    31          Method directBufferCleanerCleanX = null;
    32          boolean v;
    33          try {
    34              directBufferCleanerX = Class.forName("java.nio.DirectByteBuffer").getMethod("cleaner");
    35              directBufferCleanerX.setAccessible(true);
    36              directBufferCleanerCleanX = Class.forName("sun.misc.Cleaner").getMethod("clean");
    37              directBufferCleanerCleanX.setAccessible(true);
    38              v = true;
    39          } catch (Exception e) {
    40              v = false;
    41          }
    42          CLEAN_SUPPORTED = v;
    43          directBufferCleaner = directBufferCleanerX;
    44          directBufferCleanerClean = directBufferCleanerCleanX;
    45      }
    46
    47      /**
    48       * Destroy the given {@link ByteBuffer} if possible
    49       */
    50      public static void destroy(ByteBuffer buffer) {
    51          if (CLEAN_SUPPORTED && buffer.isDirect()) {
    52              try {
    53                  Object cleaner = directBufferCleaner.invoke(buffer);
    54                  directBufferCleanerClean.invoke(cleaner);
    55              } catch (Exception e) {
    56                  // silently ignore exception
    57              }
    58          }
    59      }
    60
    61      private ByteBufferUtil() {
    62          // Utility class
    63      }
    64  }