| /* |
| * Licensed to the Apache Software Foundation (ASF) under one |
| * or more contributor license agreements. See the NOTICE file |
| * distributed with this work for additional information |
| * regarding copyright ownership. The ASF licenses this file |
| * to you under the Apache License, Version 2.0 (the |
| * "License"); you may not use this file except in compliance |
| * with the License. You may obtain a copy of the License at |
| * |
| * http://www.apache.org/licenses/LICENSE-2.0 |
| * |
| * Unless required by applicable law or agreed to in writing, software |
| * distributed under the License is distributed on an "AS IS" BASIS, |
| * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. |
| * See the License for the specific language governing permissions and |
| * limitations under the License. |
| */ |
| |
| package arq.examples; |
| |
| |
| // The ARQ application API. |
| import org.apache.jena.atlas.io.IndentedWriter ; |
| import org.apache.jena.query.* ; |
| import org.apache.jena.rdf.model.Model ; |
| import org.apache.jena.rdf.model.ModelFactory ; |
| import org.apache.jena.rdf.model.Resource ; |
| import org.apache.jena.vocabulary.DC ; |
| |
| /** Example 2 : Execute a simple SELECT query on a model |
| * to find the DC titles contained in a model. |
| * Show how to print results twice. */ |
| |
| public class ExQuerySelect2 |
| { |
| static public final String NL = System.getProperty("line.separator") ; |
| |
| public static void main(String[] args) |
| { |
| // Create the data. |
| // This wil be the background (unnamed) graph in the dataset. |
| Model model = createModel() ; |
| |
| // First part or the query string |
| String prolog = "PREFIX dc: <"+DC.getURI()+">" ; |
| |
| // Query string. |
| String queryString = prolog + NL + |
| "SELECT ?title WHERE {?x dc:title ?title}" ; |
| |
| Query query = QueryFactory.create(queryString) ; |
| // Print with line numbers |
| query.serialize(new IndentedWriter(System.out,true)) ; |
| System.out.println() ; |
| |
| // Create a single execution of this query, apply to a model |
| // which is wrapped up as a Dataset |
| |
| // Or QueryExecutionFactory.create(queryString, model) ; |
| try(QueryExecution qexec = QueryExecutionFactory.create(query, model)) { |
| // A ResultSet is an iterator - any query solutions returned by .next() |
| // are not accessible again. |
| // Create a ResultSetRewindable that can be reset to the beginning. |
| // Do before first use. |
| |
| ResultSetRewindable rewindable = ResultSetFactory.makeRewindable(qexec.execSelect()) ; |
| ResultSetFormatter.out(rewindable) ; |
| rewindable.reset() ; |
| ResultSetFormatter.out(rewindable) ; |
| } |
| } |
| |
| public static Model createModel() |
| { |
| Model m = ModelFactory.createDefaultModel() ; |
| |
| Resource r1 = m.createResource("http://example.org/book#1") ; |
| Resource r2 = m.createResource("http://example.org/book#2") ; |
| |
| r1.addProperty(DC.title, "SPARQL - the book") |
| .addProperty(DC.description, "A book about SPARQL") ; |
| |
| r2.addProperty(DC.title, "Advanced techniques for SPARQL") ; |
| |
| return m ; |
| } |
| } |