Query

Component description

The MKSearch query component is responsible for handling HTTP-based search queries by general users. It's implementation is currently in the form of a single HttpQuery servlet class that formulates queries via an SeRQLQueryBuilder, passes these to a file-based Sesame RDF repository and displays the results with a custom ResultsRenderer type.

More ResultsRenderer types

There are currently two result renderer types, which are very basic; a TextResultsRenderer and XhtmlResultsRenderer. At least one further type, RssResultsRenderer is required to generate an RSS feed for a standing query.

One issue for the RSS feed is the need to include the query URI itself in the output, which will require a more sophisticated renderer interface.

Task progress: Refactored the original ResultRenderer types into a more generic form that are insulated from the specifics of the Sesame API.

• Completed text, XHTML and RSS result renderers.

Results paging

The results renderer interface originally had no method for paging the results of a query nor controlling the number of results per page.

• Completed result paging for XhtmlResultRenderer

Query test documents

The query features need simple test case documents to verify query interpretation and retreival.

Task progress:

• Prepared a set of "cat and dog" test documents and verified query processing.

Dynamic query form

The main search interface will initially present a simple subject query field and search button. To enable users to search on any relevant predicate, additional search fields will be called-up through a query builder form.

Task progress

• Completed JSP QueryBuilderTag and tested manually.
• Completed JSP QueryResultTag and tested manually.
• Complted basic JSP result pages for Text, RSS and XHTML format results.

Results cacheing

Standing RSS feeds and results paging will also require a result cache to optimise performance on the server side. However, the cache mechanism also needs to be integrated with the repository management interface, so that stale results are purged.

More complex query construction

The current query builder only constructs queries that join a series of RDF triples, not extended queries that specify the RDF type of the object. Such an extension will require changes to the structure of the SeRQLQueryBuilder class, possibly a set of supporting query construct classes.

AND and AND NOT queries

The query builder should interpret the + and - symbols immediately before a word to mean AND and AND NOT respectively.