code: /*
   * Copyright 2012-2018 Chronicle Map Contributors
   *
   * Licensed 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 net.openhft.chronicle.hash.impl.util;
  
  import net.openhft.chronicle.core.Jvm;
  import org.slf4j.Logger;
  import org.slf4j.LoggerFactory;
  
  import java.lang.reflect.InvocationTargetException;
  import java.lang.reflect.Method;
  
  public class CleanerUtils {
  
      private static final Method CREATE_METHOD;
      private static final Method CLEAN_METHOD;
  
      static {
          try {
              Class<?> cleanerClass = Class.forName(Jvm.isJava9Plus() ? "jdk.internal.ref.Cleaner" : "sun.misc.Cleaner");
              CREATE_METHOD = cleanerClass.getDeclaredMethod("create", Object.class, Runnable.class);
              Jvm.setAccessible(CREATE_METHOD);
              CLEAN_METHOD = cleanerClass.getDeclaredMethod("clean");
              Jvm.setAccessible(CLEAN_METHOD);
          } catch (ClassNotFoundException | NoSuchMethodException e) {
              Jvm.error().on(CleanerUtils.class, "Unable to initialise CleanerUtils", e);
              throw new RuntimeException(e);
          }
      }
  
      public static Cleaner createCleaner(Object ob, Runnable thunk) {
          try {
              Object cleanerInstance = CREATE_METHOD.invoke(null, ob, thunk);
              return () -> doClean(cleanerInstance);
          } catch (IllegalAccessException | InvocationTargetException e) {
              Jvm.error().on(CleanerUtils.class, "Unable to create cleaner", e);
              throw new RuntimeException(e);
          }
      }
  
      private static void doClean(Object cleanerInstance) {
          try {
              CLEAN_METHOD.invoke(cleanerInstance);
          } catch (IllegalAccessException | InvocationTargetException e) {
              Jvm.warn().on(CleanerUtils.class, "Failed to clean buffer", e);
          }
      }
  }
  