gistfile1.txt

   @Override
   public Lock obtainLock(LockMode mode)
   {
      ReadWriteLock readWriteLock = new ReentrantReadWriteLock(true);

      if (LockMode.READ.equals(mode))
         return readWriteLock.readLock();
      else
         return readWriteLock.writeLock();
   }

   @Override
   public <T> T performLocked(LockMode mode, Callable<T> task)
   {
      Assert.notNull(mode, "LockMode must not be null.");
      Assert.notNull(task, "Task to perform must not be null.");

      Lock lock = obtainLock(mode);
      lock.lock();

      T result;
      try
      {
         result = task.call();
      }
      catch (Exception e)
      {
         throw new ContainerException(e);
      }
      finally
      {
         lock.unlock();
      }
      return result;
   }