code: public Object continueChain()
          throws InterceptorException
      {
          if ( ! _chain.isEmpty() )
          {
              return invoke( ( Interceptor ) _chain.removeFirst() );
          }
          else
          {
              return null;
          }
      }
docs: Execute the next interceptor in the chain of interceptors.
  
  @return the object returned when the interceptor is invoked
  @throws InterceptorException the exception thrown if an error occurs while invoking the interceptor