From 82f240ebf2ae717123fd726ea9ec1a9868ee1f8d Mon Sep 17 00:00:00 2001
From: Valerian Wintner <v.d.w@hotmail.com>
Date: Sun, 14 Nov 2021 13:29:55 +0100
Subject: [PATCH] Cleanup fetching/writing.
---
src/main/java/com/kgshape/app/Query.java | 33 ++++++++++++++----------
1 file changed, 19 insertions(+), 14 deletions(-)
diff --git a/src/main/java/com/kgshape/app/Query.java b/src/main/java/com/kgshape/app/Query.java
index 3f40084..ca4c73b 100644
--- a/src/main/java/com/kgshape/app/Query.java
+++ b/src/main/java/com/kgshape/app/Query.java
@@ -13,12 +13,13 @@ import org.apache.logging.log4j.core.config.DefaultConfiguration;
import java.io.FileNotFoundException;
import java.io.FileOutputStream;
import java.io.IOException;
+import java.nio.file.FileSystemNotFoundException;
/**
- * See: https://jena.apache.org/documentation/query/app_api.html
+ * Queries a remote endpoint.
*/
public class Query {
- public static void main(String[] args) {
+ public static void main(String[] args) throws IOException {
// https://stackoverflow.com/questions/41442024/basicconfigurator-replacement-in-log4j2
Configurator.initialize(new DefaultConfiguration());
Configurator.setRootLevel(Level.INFO);
@@ -45,23 +46,27 @@ public class Query {
// You can also open this endpoint in the browser and test the above query
String endpoint = "https://dbpedia.org/sparql";
+ Model fetchedModel = fetchConstruct(endpoint, construct_query);
+ writeModel(fetchedModel, "rdf_file.ttl");
+ }
+
+ public static Model fetchConstruct(String endpoint, String query) {
// https://jena.apache.org/documentation/query/sparql-remote.html
- QueryExecution qexec = QueryExecutionFactory.sparqlService(endpoint, construct_query);
+ // Also see: https://jena.apache.org/documentation/query/app_api.html
+ QueryExecution qexec = QueryExecutionFactory.sparqlService(endpoint, query);
Model resultModel = qexec.execConstruct();
+ qexec.close();
+ return resultModel;
+ }
-// RDFDataMgr.write(System.out, resultModel, Lang.TURTLE);
+ public static void writeModel(Model model, String filename) throws FileSystemNotFoundException, IOException {
+// RDFDataMgr.write(System.out, resultModel, Lang.TURTLE); // Write it to stdout
- try (FileOutputStream fos = new FileOutputStream("rdf.ttl")) {
+ try (FileOutputStream fos = new FileOutputStream(filename)) {
// See: https://jena.apache.org/documentation/io/rdf-output.html#opt-turtle-trig
- RDFDataMgr.write(fos, resultModel, Lang.TURTLE);
- } catch (FileNotFoundException e) {
- e.printStackTrace();
- } catch (IOException e) {
- e.printStackTrace();
+ RDFDataMgr.write(fos, model, Lang.TURTLE);
+ } catch (Exception e) {
+ throw e;
}
-
- qexec.close();
-
- System.out.println("Hello Query!");
}
}
--
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