package org.springside.modules.utils;



/*

 * Copyright 2010, the original author or authors.  All rights reserved.

 */



import java.lang.reflect.Field;

import org.apache.log4j.Logger;

import sun.misc.Unsafe;



/**

 * 获取{@link sun.misc.Unsafe}实例<br>

 * 从rt.jar包中反编译该类获取的信息

 *

 * <pre>

 *

 * package sun.misc;

 *

 *  import java.lang.reflect.Field;

 *  import java.lang.reflect.Modifier;

 *  import java.security.ProtectionDomain;

 *  import sun.reflect.Reflection;

 *

 *  public final class Unsafe

 *  {

 *  private static final Unsafe theUnsafe;

 *  public static final int INVALID_FIELD_OFFSET = -1;

 *

 *  private static native void registerNatives();

 *

 *  public static Unsafe getUnsafe()

 *  {

 *  Class localClass = Reflection.getCallerClass(2);

 *  if (localClass.getClassLoader() != null)

 *  throw new SecurityException(&quot;Unsafe&quot;);

 *  return theUnsafe;

 *  }

 * static

 *  {

 *  registerNatives();

 *

 *  theUnsafe = new Unsafe();

 *  }

 * ..........................

 * </pre>

 *

 * @author <a href="mailto:xiao_jiang51@163.com">xiao jiang</a>

 * @version %I%, %G%

 * @history 2010-12-23

 */

public class UnsafeSupport {

  private static Logger log = Logger.getLogger(UnsafeSupport.class);



  private static Unsafe unsafe;



  static {

    Field field;

    try {

      // 由反编译Unsafe类获得的信息

      field = Unsafe.class.getDeclaredField("theUnsafe");

      field.setAccessible(true);

      // 获取静态属性,Unsafe在启动JVM时随rt.jar装载

      unsafe = (Unsafe) field.get(null);

    } catch (Exception e) {

      log.error("Get Unsafe instance occur error", e);

    }

  }



  /**

   * 获取{@link Unsafe }

   */

  public static Unsafe getInstance() {

    return unsafe;

  }



  public static void main(String[] args) {



  }

}