An aspect-oriented approach to bypassing middleware layers

Abstract

The layered architecture of middleware platforms (such as CORBA, SOAP, J2EE) is a mixed blessing. On the one hand, layers provide services such as demarshaling, session management, request despatching, quality-of-service (QoS) etc. In a typical middleware platform, every request passes through each layer, whether or not the services provided by that layer are needed for that specific request. This rigid layer processing can lower overall system throughput, and reduce availability and/or increase vulnerability to denial-of-service attacks. For use cases where the response is a simple function of the request input parameters, bypassing middleware layers may be permissible and highly advantageous. Unfortunately, if an application developer desires to selectively bypass the middleware, and process some requests in the lower layer, she has to write platform-specific, intricate low-level code. To evade this trap, we propose to extend the middleware platform with new aspect-oriented modeling syntax, code generation tools, and a development process for building bypassing implementations. Bypassing implementations provide better use of server's resources, leading to better overall client experience. Our core contribution is this idea: aspect-oriented extensions to IDL, additional code generation, along with an enhanced run-time, can enable application developers to conveniently bypass middleware layers when they are not needed, thus improving the server's performance and providing more "operational headroom". Copyright 2007 ACM.