Classpects: unifying aspect- and object-oriented language design

ABSTRACT

The contribution of this work is the design, implementation, and early evaluation of a programming language that unifies classes and aspects. We call our new module construct the classpect. We make three basic claims. First, we can realize a unified design without significantly compromising the expressiveness of current aspect languages. Second, such a design improves the conceptual integrity of the programming model. Third, it significantly improves the compositionality of aspect modules, expanding the program design space from the two-layered model of AspectJ-like languages to include hierarchical structures. To support these claims, we present the design and implementation of Eos-U, an AspectJ-like language based on C# that supports classpects as the basic unit of modularity. We show that Eos-U supports layered designs in which classpects separate integration concerns flexibly at multiple levels of composition. The underpinnings of our design include support for aspect instantiation under program control, instance-level advising, advising as a general alternative to object-oriented method invocation and overriding, and the provision of a separate join-point-method binding construct.

REFERENCES

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INDEX TERMS

Primary Classification:
  D. Software
  D.1 PROGRAMMING TECHNIQUES
      D.1.5 Object-oriented Programming

Additional Classification:
  D. Software
  D.2 SOFTWARE ENGINEERING
      D.2.2 Design Tools and Techniques
          Subjects: Object-oriented design methods; Modules and interfaces
      D.2.3 Coding Tools and Techniques
          Subjects: Object-oriented programming
  D.3 PROGRAMMING LANGUAGES
      D.3.3 Language Constructs and Features
          Subjects: Classes and objects; Modules, packages

General Terms:
Design, Human Factors, Languages

Keywords:
aspect-oriented, classpect, join point-method binding