Several reflective architectures have attempted to improve
meta-object reuse by supporting composition of meta-objects, but
have done so using limited mechanisms such as Chains of
Responsibility. We advocate the adoption of the Composite pattern
to define
meta-configurations. In the meta-object protocol
(MOP) of
Guaraná, a
composer meta-object can control
reconfiguration of its component meta-objects and their
interactions with base-level objects, resolving conflicts that may
arise and establishing meta-level
security policies.
Guaraná is currently implemented as an extension of
Kaffe
OpenVM
TM, a free implementation of the Java
1 Virtual Machine.
Nevertheless, most design decisions presented in this paper can be
transported to other programming languages and MOPs, improving their
flexibility, reconfigurability, security and meta-level code reuse.
We present performance figures that show that it is possible to
introduce run-time reflection support in a language like Java
without much impact on execution speed.
