empire-10.java

// Lastly, we can use the query API to run arbitrary sparql queries
// create a jpql-style partial SPARQL query (JPQL is currently unsupported)
Query aQuery = aManager.createQuery("where { ?result frbr:embodiment ?manifest." +
                        " ?foo <http://purl.org/goodrelations/v1#typeOfGood> ?manifest . " +
                        " ?foo <http://purl.org/goodrelations/v1#hasPriceSpecification> ?price. " +
                        " ?price <http://purl.org/goodrelations/v1#hasCurrencyValue> ?value. " +
                        " ?price <http://purl.org/goodrelations/v1#hasCurrency> \"USD\"@en." +
                        " filter(?value > ??min). }");
  
// this query should return instances of type Book
aQuery.setHint(RdfQuery.HINT_ENTITY_CLASS, Book.class);
  
// set the parameter in the query to the value for the min price
// parameters are prefixed with ?? -- this differs slightly from JPQL
aQuery.setParameter("min", 30);
  
// now execute the query to get the list of all books which are $30 USD
List aResults = aQuery.getResultList();
  
// 233 results
System.err.println("Num Results:  " + aResults.size());
  
// print the titles of the first five results
for (int i = 0; i < 5; i++) {
    Book aBookResult = (Book) aResults.get(i);
    System.err.println(aBookResult.getTitle());
}