SemWebsite — using RDF/OWL in JSP

The aim of this project is to realize custom JSP tags & functions for using Semantic Web ontologies (RDF/OWL) in JSP pages.

Download & install

Download (with all necessary libraries): semwebsite.war (7.1 Mb). Last modified: 2004/08/07 13:26 GMT+08:00.

Install: download this example project and deploy it into your web server (tested with Tomcat 5 & Resin 3);

Brief description of supported features

Tags: query, queryFirst, queryValue

Tag query executes query (RDQL or BRQL) and save results in variable, e.g.:

	<rdf:query var="peoples" language="BRQL">
		SELECT ?name,?homepage
		WHERE
			(?person foaf:knows ?somebody)
			(?somebody foaf:name ?name)
		OPTIONAL
			(?somebody foaf:homepage ?homepage)
		<rdf:param name="person" resource="${personURI}"/>
	</rdf:query>

	<c:if test="${!empty peoples}">
		<ul>
		<c:forEach var="somebody" items="${peoples.rows}">
			<li>
			<c:choose>
				<c:when test="${!empty somebody.homepage}"><a href="${somebody.homepage}">${somebody.name}</a></c:when>
				<c:otherwise>${somebody.name}</c:otherwise>
			</c:choose>
		</c:forEach>
		</ul>
	</c:if>

Tag queryFirst executes query and save only first row, e.g.:

	<rdf:queryFirst var="person">
		SELECT
			?name,?homepage,?image
		WHERE
			(?person foaf:name ?name)
			(?person foaf:homepage ?homepage)
			(?person foaf:img ?image)
		<rdf:param name="person" resource="${personURI}"/>
	</rdf:queryFirst>

	<a href="${person.homepage}"><img alt="${person.name}" src="${person.image}"></a>

Tag queryValue executes query & save only first value of first row.

Dot-operation

Operators resource.property and resource[property] return property of resource, e.g.:

	<c:set var="person" value="${rdf:resource('http://www.ideaspace.net/users/wkearney/foaf.xrdf#wkearney99')}"/>

	<table align=right><tr><td><img src="${person.img}"></td></tr></table>

	<div><a href="${person['homepage']}">${person['foaf:name']}</a> knows:</div>

	<ul>
	<c:forEach var="somebody" items="${rdf:all(person.knows)}">
		<li>
		<c:choose>
			<c:when test="${!empty somebody.homepage}"><a href="${somebody.homepage}">${somebody.name}</a></c:when>
			<c:otherwise>${somebody.name}</c:otherwise>
		</c:choose>
	</c:forEach>
	</ul>

For using of dot-operation resources really must have type ru.krasu.semweb.semwebsite.Node and you can obtain such resources by function rdf:resource or by means of queries (see examples above).

Add operation

Tag add adds N3 statements to model, e.g.:

	<rdf:add>
		[ rdf:type ex3:String; ex3:value ?string ].
		<rdf:param name="string" literal="${param.string}"/>
	</rdf:add>

Configuration

Base RDF model (file or URL) and others parameters are stated in WEB-INF/web.xml file. If you want to use Jena persistent models, then edit ont-policy.rdf file in folder WEB-INF/classes/conf/ (see example at the end of file) and simply import model by public URL from your base RDF model.

Other examples

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