1. Developing for the
Semantic Web
by Timea Turdean
21.11.2015
#devfest15
Vienna

2. SEMANTIC WEB
&
LINKED DATA
2 http://dbpedia.org/resource/Sir_Tim_Berners_Lee
Triple
http://example.org/myProject/Triple
the form of
subject–predicate–object
expressions
<?s ?p ?o>
World Wide Web Consortium
(w3.org)
English computer scientists
RDF
http://dbpedia.org/resource/Resource_Description_Framework
http://www.w3.
org/2004/02/skos/core#de
finition
http://www.w3.org/1999/02/22-rdf-
syntax-ns#type http://example.org/Timea-
Custom-
Scheme/contained_in
http://example.org/Timea-
Custom-
Scheme/knows_to_use

3. 3

4. Place your screenshot here
4Web
Application
http://preview.poolparty.biz/sparqlingCocktails/cocktails

5. 5FEATURES &
FUNCTIONALITY
● Tap into your Linked Data endpoint
● Query Linked Data
● Display your Linked Data
● Display OPEN Linked Data
● The power of Linked Data
● BONUS *An improved search

6. Tap into your
Linked Data
endpoint
▸ data contains:
6 ▸ data is available
through a
SPARQL
endpoint

7. Tap into your
Linked Data
endpoint
<http://vocabulary.semantic-web.at/cocktails/8f09ee6f-d5b9-4b8a-aa17-b0665fae4e83>
<http://www.w3.org/1999/02/22-rdf-syntax-ns#type> <http://www.w3.
org/2004/02/skos/core#Concept> .
<http://vocabulary.semantic-web.at/cocktails/8f09ee6f-d5b9-4b8a-aa17-b0665fae4e83>
<http://www.w3.org/2004/02/skos/core#prefLabel> "Brandy"@en .
<http://vocabulary.semantic-web.at/cocktails/8f09ee6f-d5b9-4b8a-aa17-b0665fae4e83>
<http://www.w3.org/2004/02/skos/core#altLabel> "Grape spirit"@en .
<http://vocabulary.semantic-web.at/cocktails/8f09ee6f-d5b9-4b8a-aa17-b0665fae4e83>
<http://www.w3.org/2004/02/skos/core#definition> "Brandy (from brandywine, derived from
Dutch brandewijnu2014"burnt wine") is a spirit produced by distilling wine. Brandy
generally contains 35u201360% alcohol by volume and is typically taken as an after-
dinner drink. Some brandies are aged in wooden casks, some are coloured with caramel
colouring to imitate the effect of aging, and some brandies are produced using a
combination of both aging and colouring."@en .
<http://vocabulary.semantic-web.at/cocktails/8f09ee6f-d5b9-4b8a-aa17-b0665fae4e83>
<http://www.w3.org/2004/02/skos/core#narrower> <http://vocabulary.semantic-web.
at/cocktails/16b625c5-3930-4cf8-a75b-b25e72f2bfb6> .
<http://vocabulary.semantic-web.at/cocktails/16b625c5-3930-4cf8-a75b-b25e72f2bfb6>
<http://www.w3.org/2004/02/skos/core#prefLabel> "Calvados"@en .
7

8. SPARQL
8 SELECT * WHERE
{
?s ?p ?o
}
SELECT * WHERE
{
?s ?p ?o
}

9. Query
Linked Data
▸ Give me all Alcoholic Beverages:
PREFIX skos:<http://www.w3.org/2004/02/skos/core#>
SELECT ?label WHERE {
<http://vocabulary.semantic-web.
at/cocktails/f3000285-36b0-4ffe-af90-
740c2dd8fff5> skos:narrower ?o .
?o skos:prefLabel ?label .
}
▸ Results:
"Brandy"@en
"Fortified wine"@en
"Gin"@en
"Liqueur"@en
"Rum"@en
"Schnapps"@en
"Tequila"@en
"Vodka"@en
"Whisky"@en
"Wine"@en
9

10. Tap into your
Linked Data
endpoint
public class SPARQLendpointConnection extends HttpClient {
URL sparqlEndpointURL = null;
NameValuePair queryParam = new NameValuePair( "query", "QUERY");
List<NameValuePair> urlParams = new ArrayList() ;
List<Header> headers = new ArrayList<>() ;
public SPARQLendpointConnection (URL sparqlEndpointURL) {
this.sparqlEndpointURL = sparqlEndpointURL ;
this.addQueryParameter( "query", "QUERY");
this .addQueryParameter( "content-type" , "application/json" );
super .getParams().setParameter( "http.protocol.version" , HttpVersion. HTTP_1_1);
super .getParams().setParameter( "http.protocol.content-charset" , "UTF-8");
}
public void addQueryParameter (String key , String value) {
if (value.equals( "QUERY")) {
this.queryParam = new NameValuePair(key , value);
} else {
this.urlParams.add(new NameValuePair(key , value));
}
} [...]
}
10

11. Display your
Linked Data
public class SPARQLendpointConnection extends HttpClient {
public TupleQueryResult runAndParseSelectQuery (String query) throws IOException {
InputStream in = null;
TupleQueryResult tqr = null;
try {
in = IOUtils. toInputStream(runSelectQuery(query)) ;
tqr = QueryResultIO. parse(in, TupleQueryResultFormat. JSON);
return tqr;
} catch (QueryResultParseException | TupleQueryResultHandlerException |
UnsupportedQueryResultFormatException ex) {
throw new IOException(ex) ;
} finally {
if (in != null) {
in.close() ;
}
}
}
}
11

12. Display your
Linked Data
public class SPARQLendpointConnection extends HttpClient {
public String runSelectQuery (String query) throws IOException {
PostMethod post = new PostMethod( this.sparqlEndpointURL .toString()) ;
NameValuePair[] params = this.urlParams.toArray(new NameValuePair[ this.urlParams.
size() + 1]);
params[(params. length - 1)] = new NameValuePair( queryParam .getName() , query);
post.setRequestBody(params) ;
for (Header h : this.headers) { post.addRequestHeader(h) ; }
int statusCode ;
String response ;
try {
statusCode = super.executeMethod(post) ;
response = post.getResponseBodyAsString() ;
if (statusCode != HttpStatus. SC_OK) {
System. out.println(statusCode) ;
}} finally {
post.releaseConnection() ;
}
return response;
}}
12

13. Tap into your
Linked Data
endpoint
import org.apache.commons.httpclient.* ;
import org.apache.commons.httpclient.methods.PostMethod ;
13
org.apache.commons.httpclient.jar
commons.io.jar
import org.apache.commons.io.IOUtils ;
sesame-query.jar
import org.openrdf.query.TupleQueryResult ;
import org.openrdf.query.TupleQueryResultHandlerException ;
sesame-queryresultio-api.jar; sesame-queryresultio-sparqljson.jar
import org.openrdf.query.resultio.QueryResultIO ;
import org.openrdf.query.resultio.QueryResultParseException ;
import org.openrdf.query.resultio.TupleQueryResultFormat ;
import org.openrdf.query.resultio.UnsupportedQueryResultFormatException ;

14. Display your
Linked Data
public void test() throws Exception {
String value = "";
SPARQLendpointConnection myConncetion = new SPARQLendpointConnection( new URL("http:
//vocabulary.semantic-web.at/PoolParty/sparql/cocktails" ));
TupleQueryResult tqr = myConnection.runAndParseSelectQuery(
"PREFIX skos:<http://www.w3.org/2004/02/skos/core#> n" +
"SELECT ?label WHERE { n" +
"<http://vocabulary.semantic-web.at/cocktails/f3000285-36b0-4ffe-af90-740c2dd8fff5>
skos:narrower ?p . n" +
"?p skos:prefLabel ?label n" +
"}");
BindingSet bs = null;
try {
while (tqr.hasNext()) {
bs = tqr.next() ;
value = bs.getValue( "label").toString() ;
System.out.println(bs.getValue( "label"));
}} finally {
tqr.close() ;
}}
14

15. Display your
Linked Data
"Brandy"@en
"Fortified wine"@en
"Gin"@en
"Liqueur"@en
"Rum"@en
"Schnapps"@en
"Tequila"@en
"Vodka"@en
"Whisky"@en
"Wine"@en
15 RESULTS

16. Display your
Linked Data
private ModelAndView mavChooseIngredients;
mavChooseIngredients = new ModelAndView( "cocktails/index" );
mavChooseIngredients .addObject( "myMenu", this.retrieveMainAlcoholicBeverages()) ;
[..]
public List<BindingSet> retrieveMainAlcoholicBeverages () throws
IOException , QueryEvaluationException {
return QueryResults. asList(myConnection .runAndParseSelectQuery(
"PREFIX skos:<http://www.w3.org/2004/02/skos/core#> n" +
"SELECT ?label WHERE { n" +
"<http://vocabulary.semantic-web.at/cocktails/f3000285-36b0-4ffe-af90-
740c2dd8fff5> skos:narrower ?p . n" +
"?p skos:prefLabel ?label n" +
"}"
));
}
16

17. Display your
Linked Data
<%@taglib prefix="c" uri="http://java.sun.com/jsp/jstl/core " %>
<%@taglib prefix="fn" uri="http://java.sun.com/jsp/jstl/functions " %>
[...]
<c:forEach items="${myMenu}" var="bindingSet ">
<li class="entity">
${bindingSet.getValue( 'label').stringValue() }
</li>
</c:forEach>
17 index.jsp

18. Display OPEN
Linked Data
DBpedia SPARQL endpoint:
▸ http://dbpedia.org/sparql
SELECT * WHERE {
<http://dbpedia.org/resource/Negroni>
<http://dbpedia.org/ontology/abstract>
?abstract
}
18

19. The POWER
of
Linked data
▸ easy change of data
▸ cost efficient
▸ graph algorithms
19

20. Place your screenshot here
20An improved SEARCH
Faceted search
http://preview.poolparty.biz/sparqlingCocktails/search

21. Thank you!
21

22. Connect
Timea Turdean
Technical Consultant, Semantic Web Company
▸ timea.turdean@gmail.com
▸ http://at.linkedin.com/in/timeaturdean
▸ http://timeaturdean.com
22
© Semantic Web Company - http://www.semantic-web.at/ and http://www.poolparty.biz/

23. ▸ LD2014 picture slide3- http://data.dws.informatik.uni-
mannheim.de/lodcloud/2014/
▸ Linked Data principles: http://www.w3.
org/DesignIssues/LinkedData.html
▸ Introduction to Semantic Web: http://timeaturdean.
com/introduction-semantic-web/
23Resources