Existing DAML applications generally
retrieve one or more DAML pages ahead of time
and then process them.
The use of URIs to name DAML+OIL instances
offers the opportunity to retrieve them dynamically,
as they are needed.
This page describes a
Jena
model
and a simple
viewer
designed to exercise and demonstrate this capability.
Approach
org.daml.jena.DynamicModel
is a wrapper around an existing Jena
org.hp.hpl.mesa.rdf.jena.model.Model
that traps
methods such as
Resource.listStatements
and causes the page indicated in the subject URI
to be loaded if it hasn't been loaded already.
org.daml.jena.DynamicViewer
is a simplified version of the
DAML/RDF Viewer
that dynamically queries an underlying
Jena model
whenever the statements for a given subject are viewed.
Downloads
The following files are available for download:
- DynamicModel.java
- implements a Jena model where resources are retrieved as references
- DynamicViewer.java
- provides a simple viewer for DynamicModel and other Jena models
- PromptAuthenticator.java
- prompts the user for a password when accessing password-protected pages.
Possible Future Directions
- the current implementation is a prototype
that needs to be generalized to provide consistent support
for all methods
- dynamic loading probably belongs in the core of
Jena itself
- provide feedback on the loading of large and/or distant pages
- accommodate non-resolvable URIs more gracefully
- provide an implementation compatible with
com.hp.hpl.jena.daml.DAMLModel
from the Jena DAML API
Author
Mike Dean
$Id: index.xml,v 1.4 2003/08/11 23:57:55 mdean Exp $
