code: public void locked (@Nonnull final Runnable aRunnable)
    {
      ValueEnforcer.notNull (aRunnable, "Runnable");
  
      lock ();
      try
      {
        aRunnable.run ();
      }
      finally
      {
        unlock ();
      }
    }
docs: Execute the provided runnable in a read lock.
  
  @param aRunnable
  Runnable to be executed. May not be <code>null</code>.