Abstract
Metadata-based frameworks are those that process their logic based on the metadata of the classes whose instances they are working with. Many recent frameworks use this to get a higher reuse level and to be more suitably adapted to the application needs. However, there is not yet a complete best practices documentation or reference architecture for the development of frameworks by using the metadata approach. As a result, this paper presents a pattern language that addresses preliminarily the internal structure of metadata-based frameworks, helping in the understanding and development of such kind of framework. Copyright 2009.