A Declarative Approach for Designing and 
Developing Adaptive Components






declarative approach, Aspect-Oriented Programming


An adaptive component is a component 
that is able to adapt its behavior 
to different execution contexts. Building an adaptive 
application is difficult because of the implied 
component dependencies and the lack of language 
support. As a result, code that implements 
adaptation is often tangled, which hinders maintenance 
and evolution. To overcome this problem, we 
propose a declarative approach to program adaptation. 
This approach makes explicit specific issues of 
adaptation. The programmer can focus on the 
basic features of the application and separately 
provide clear and concise adaptation information. Concretely, 
we define adaptation classes, that enrich Java 
classes with adaptive behaviors. A dedicated compiler 
automatically generates Java code that fully implements 
the adaptive features. Moreover, these declarations can 
be checked for consistency to provide additional 
safety guarantees. To present and assess our 
approach, we use as an example an 
adaptive sound encoder in an audio-conference application. 
We show the problems of a traditional 
implementation using design patterns and how these 
problems are elegantly solved using adaptation classes.