Interception Patterns

Short Description
A possible solution (like the one present in Smalltalk for the observer ….. Bob Hinkle, Reflective Programming in Smalltalk. Tutorial #11, OOPSLA ‘93. …

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Content
Interception Patterns
Andrés Fortier. Juan Cappi. Gustavo Rossi.
LIFIA-Facultad de Informática-UNLP, Argentina
{andres,jcappi,gustavo}@lifia.info.unlp.edu.ar
Abstract. Developing applications that support evolution in a seamless way is not an easy task; in an early
design stage, some concepts may be confused or some potential functionality not foreseen, resulting in bad
separations of concerns. In this kind of designs, future changes may imply huge modifications if a highquality
object-oriented model is the desired product. In theory, object oriented programming is supposed
to help us to cope with sudden changes, but that doesn’t mean that, because we use an object oriented
language, all the problems will be solved; in the end, the design is up to us. In this paper we show how to
introduce a new spot in an object oriented design, to allow better behavior delegation. We will also show
how flexible architectures can be built around any of the patterns that conform this pattern system,
allowing to cope with new behavior in a “peaceful” way.
1 Motivation
To get started, let’s think of the problem that appears when we try to extend an application to support new
features (for…