Added example for the Resource API.

Author: Aklakan

jena-examples/src/main/java/arq/examples/ExampleDBpediaViaRemoteDataset2.java

@@ -0,0 +1,48 @@
+package arq.examples;
+
+import java.util.List;
+
+import org.apache.jena.atlas.iterator.Iter;
+import org.apache.jena.query.Dataset;
+import org.apache.jena.query.DatasetFactory;
+import org.apache.jena.rdf.model.Model;
+import org.apache.jena.rdf.model.RDFNode;
+import org.apache.jena.rdf.model.Resource;
+import org.apache.jena.rdf.model.Statement;
+import org.apache.jena.rdflink.RDFLinkHTTP;
+import org.apache.jena.rdflink.dataset.DatasetGraphOverRDFLink;
+import org.apache.jena.vocabulary.RDFS;
+
+/**
+ * Example that uses the {@link Resource} API over an HTTP-backed DatasetGraph.
+ * Note, that each access fires an HTTP request. Hence, this pattern is only
+ * meaningful lightweight infrequent lookups.
+ * In general, it is recommended to first create local in-memory snapshots of
+ * a remote endpoint's data using e.g. CONSTRUCT queries first.
+ */
+public class ExampleDBpediaViaRemoteDataset2 {
+    public static void main(String... args) {
+        Dataset ds = DatasetFactory.wrap(new DatasetGraphOverRDFLink(() ->
+            RDFLinkHTTP.newBuilder()
+                .destination("https://dbpedia.org/sparql")
+                .build()));
+
+        Model model = ds.getDefaultModel();
+        Resource r = model.getResource("http://dbpedia.org/resource/Apache_Jena");
+        List<RDFNode> list = Iter.toList(r.listProperties(RDFS.label).mapWith(Statement::getObject));
+        int n = list.size();
+        System.out.println("Got " + n + " labels from DBpedia:");
+        for (int i = 0; i < n; ++i) {
+            System.out.println((i + 1) + ": " + list.get(i));
+        }
+
+        /* Output is expected to be similar to:
+             Got 5 labels from DBpedia:
+             1: "Apache Jena"@en
+             2: "Jena (Framework)"@de
+             3: "Jena (framework)"@fr
+             4: "Jena (informatica)"@it
+                5: "아파치 제나"@ko
+        */
+    }
+}