Aspect] is a simple and practical aspect-oriented extension to Java With just a few new constructs, AspectJ provides support for modular implementation of a range of crosscutting concerns. In AspectJ's dynamic join point model, join points are well-defined points in the execution of the program; pointcuts are collections of join points; advice are special method-like constructs that can be attached to pointcuts; and aspects are modular units of crosscutting implementation, comprising pointcuts, advice, and ordinary Java member declarations. AspectJ code is compiled into standard Java bytecode. Simple extensions to existing Java development environments make it possible to browse the crosscutting structure of aspects in the same kind of way as one browses the inheritance structure of classes. Several examples show that AspectJ is powerful, and that programs written using it are easy to understand.

An overview of AspectJ

The Object Management Group's (OMG) Model Driven Architecture (MDA) strategy envisages a world where models play a more direct role in software production, being amenable to manipulation and transformation by machine. Model Driven Engineering (MDE) is wider in scope than MDA. MDE combines process and analysis with architecture. This article sets out a framework for model driven engineering, which can be used as a point of reference for activity in this area. It proposes an organisation of the modelling 'space' and how to locate models in that space. It discusses different kinds of mappings between models. It explains why process and architecture are tightly connected. It discusses the importance and nature of tools. It identifies the need for defining families of languages and transformations, and for developing techniques for generating/configuring tools from such definitions. It concludes with a call to align metamodelling with formal language engineering techniques.

Model Driven Engineering

Methods and systems consistent with the present invention provide a data processing system having a business object model reflecting the data used during a business transaction. Consistent interfaces are generated from the business object model. These interfaces are suitable for use across industries, across businesses, and across different departments within a business during a business transaction.

Consistent set of interfaces derived from a business object model

The Transmission Control Protocol.

The term model-driven engineering (MDE) is typically used to describe software development approaches in which abstract models of software systems are created and systematically transformed to concrete implementations. In this paper we give an overview of current research in MDE and discuss some of the major challenges that must be tackled in order to realize the MDE vision of software development. We argue that full realizations of the MDE vision may not be possible in the near to medium-term primarily because of the wicked problems involved. On the other hand, attempting to realize the vision will provide insights that can be used to significantly reduce the gap between evolving software complexity and the technologies used to manage complexity.

/pdf/model-driven-development-of-complex-software-a-research-1l2kfenshb.pdf

Model-driven Development of Complex Software: A Research Roadmap

Combining the best elements of these two technologies can address the key challenges associated with developing enterprise applications.

Applying model-integrated computing to component middleware and enterprise applications

The Common Object Request Broker Architecture (CORBA) object model is increasingly gaining acceptance as the industry standard, cross-platform, cross-language distributed object computing model The recent addition of the CORBA Component Model (CCM) integrates a successful component programming model from EJB, while maintaining the interoperability and language-neutrality of CORBA The CCM programming model is thus suitable for leveraging proven technologies and existing services to develop the next-generation of highly scalable distributed applications However, the CCM specification is large and complex Therefore, ORB providers have only started implementing the specification recently As with first-generation CORBA implementations several years ago, it is still hard to evaluate the quality and performance of CCM implementations Moreover, the interoperability of components and containers from different providers is not well understood yet By the end of next year, we expect that CCM providers will implement the complete specification, as well as support value-added enhancements to their implementations, just as operating system and ORB providers have done historically In particular, containers provided by the CCM component model implementation provide quality of service (QoS) capabilities for CCM components, and can be extended to provide more services to components to relieve components from implementing these functionalities in an ad-hoc way (Wang, 2000b) These container QoS extensions provide services that can monitor and control certain aspects of components behaviors that cross-cut different programming layers or require close interaction among components, containers, and operating systems As CORBA and the CCM evolve, we expect some of these enhancements will be incorporated into the CCM specification

Overview of the CORBA component model

https://www.dre.vanderbilt.edu/~schmidt/PDF/elsevier.pdf

Total quality of service provisioning in middleware and applications

QoS‐Enabled Middleware

Distributed object computing (DOC) middleware shields developers from many tedious and error-prone aspects of programming distributed applications. Without proper support from the middleware, however, it can be hard to evolve distributed applications after they are deployed. Therefore, DOC middleware should support meta-programming mechanisms, such as smart proxies and interceptors, that improve the adaptability of distributed applications by allowing their behavior to be modified without changing existing software drastically.

This paper presents three contributions to the study of metaprogramming mechanisms for DOC middleware. First, it illustrates, compares, and contrasts several meta-programming mechanisms from an application developer's perspective. Second, it outlines the key design and implementation challenges associated with developing smart proxies and portable interceptors features for CORBA. Third, it presents empirical results that pinpoint the performance impact of smart proxies and interceptors. Our goal is to help researchers and developers determine which meta-programming mechanisms best suit their application requirements.

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Nanbor Wang

Papers

Applying model-integrated computing to component middleware and enterprise applications

Overview of the CORBA component model

Total quality of service provisioning in middleware and applications

QoS‐Enabled Middleware

The design and performance of meta-programming mechanisms for object request broker middleware