Delegation Proxies: The Power of Propagation

Scoping behavioral variations to dynamic extents is useful to support non-functional requirements that otherwise result in cross-cutting code. Unfortunately, such variations are difficult to achieve with traditional reflection or aspects. We show that with a modification of dynamic proxies, called delegation proxies, it becomes possible to reflectively implement variations that propagate to all objects accessed in the dynamic extent of a message send. We demonstrate our approach with examples of variations scoped to dynamic extents that help simplify code related to safety, reliability, and monitoring

A Data Model for Semistructured Data with Partial and Inconsistent Information

With the recent popularity of the World Wide Web, an enormous amount of heterogeneous information is now available online. As a result, information about real world objects may spread over different data sources and may be partial and inconsistent. How to manipulate such semistructured data is thus a challenge. Previous work on semistructured data mainly focuses on developing query languages and systems to retrieve semistructured data. Relatively less attention has been paid to the manipulation of such data. In order to manipulate such semistructured data, we need a data model that is more expressive than the existing graph-based and tree-based ones to account for the existence of partial and inconsistent information from di erent data sources. In this paper, we propose such a data model for semistructured data that allows partial and inconsistent information and discuss how to manipulate such semistructured data