Delta Objects for JavaBeans*: Applying Database Technology to Software Components
Amy Sundermier, Suzanne W. Dietrich, and Vandana Shah
Department of Computer Science and Engineering
Arizona State University
Tempe, AZ 85287-5406
602-965-2874
{dietrich}@asu.edu
Abstract
Object deltas capture incremental changes to data in an object-oriented
environment. The DeltaObject design developed for use with an active,
declarative, object-oriented database language at Arizona State
University delegates responsibility for maintaining incremental update
information about each application object to an associated DeltaObject.
This paper demonstrates the application of active database technology
for object deltas to the emerging area of software components.
DeltaBeans, object deltas for JavaBeans* components, provide a mechanism
to monitor any arbitrary and unknown JavaBeans* component, provided that
the JavaBeans* component generates Property Change Events when the
values of its properties are modified. The paper also motivates
DeltaBeans as an initial step in an envisioned component-based system
where active rules declaratively specify component interactions.
Database technology in the form of active rules can be beneficially
incorporated into software component-based applications to minimize
"hard-coded" glue code developed by application programmers. Active
rules mesh well with the JavaBeans* component model because the Java
Reflection API is similar to database metadata and the Java Event Model
can be used to trigger rule evaluation. The paper demonstrates the use
of the Java Reflection API and Java Event Model in a simple application
example to illustrate DeltaBeans.
This research was supported by NSF grant no. IRI-9109195 and NSF grant no.
IRI-9410993.