Modular Contracts with Procedures, Annotations, Pointcuts and Advice
				  by
	  Henrique Rebelo, Ricardo Lima, and Gary T. Leavens
			     CS-TR-11-05
			   September, 2011

Abstract

There are numerous mechanisms for modularizing design by contract at
the source code level. Three mechanisms have been the main focus of
attention, metadata annotations, pointcuts and advice. The latter two
are well-known aspect-oriented programming mechanisms, and according
to the literature, fare better in achieving contract
modularization. However, previous efforts aimed at supporting contract
modularity actually hindered it. In this paper we report an enhanced
use of pointcuts and advice, and show how crosscut programming
interfaces (XPIs) can significantly improve contract modularity. In
addition, we also discuss how these XPIs can be used together with
annotations to tackle the pointcut fragility problem and minimize the
limited enforcement of XPI interface rules. We compare our approach
with the literature's in terms of code locality, well-defined
interfaces, reusability, changeability, fragility, and pluggability.

Keywords: Aspect-oriented programming, programming by contract,
modularity.

2011 CR Categories: 
D.2.1 [Software Engineering] Requirements/ Specifications — languages, AOP, AspectJ; 
D.2.2 [Software Engineering] Design Tools and Techniques — computer-aided software engineering (CASE); 
D.2.4 [Software Engineering]Software/Program Verification — Assertion
checkers, class invariants, formal methods, programming by contract,
reliability, AOP, AspectJ; 
F.3.1 [Logics and Meanings of Programs] Specifying and Verifying and
Reasoning about Programs —Assertions, invariants, pre- and
post-conditions, specification techniques.

To appear in SBLP 2011.