Optimise performance by instantiating context only once

Author: leonardehrenfried

application/src/ext-test/java/org/opentripplanner/ext/ojp/trias/OjpMapperTest.java

@@ -109,6 +109,6 @@ void ojpToTrias() {
       RESOLVE_FEED_LANG
     );
     var ojp = mapper.mapCalls(List.of(new CallAtStop(TRIP_TIMES_ON_DATE, WALK_TIME)), timestamp);
-    OjpToTriasTransformer.transform(ojp, new PrintWriter(System.out));
+    OjpToTriasTransformer.ojpToTrias(ojp, new PrintWriter(System.out));
   }
 }

application/src/ext-test/java/org/opentripplanner/ext/ojp/trias/OjpToTriasTransformerTest.java

@@ -38,7 +38,7 @@ void stopEventRequest(String name) throws JAXBException, TransformerException {
   @Test
   void error() {
     var ojp = ErrorMapper.error("An error occurred", ZDT);
-    var actual = OjpToTriasTransformer.transform(ojp);
+    var actual = OjpToTriasTransformer.ojpToTrias(ojp);
     var file = LOADER.extTestResourceFile("error.xml");
     var original = readFile(file);
     writeFile(file, actual);

application/src/ext/java/org/opentripplanner/ext/ojp/trias/OjpToTriasTransformer.java

@@ -29,32 +29,31 @@ class OjpToTriasTransformer {
     "trias_to_ojp2.0_request.xslt"
   );
 
-  static String transform(OJP ojp) {
+  private static final JAXBContext CONTEXT = jaxbContext();
+
+  static String ojpToTrias(OJP ojp) {
     var writer = new StringWriter();
-    transform(ojp, writer);
+    ojpToTrias(ojp, writer);
     return writer.toString();
   }
 
-  static void transform(OJP ojp, Writer writer) {
+  static void ojpToTrias(OJP ojp, Writer writer) {
     try {
-      var context = JAXBContext.newInstance(OJP.class);
-      var marshaller = context.createMarshaller();
+      var marshaller = CONTEXT.createMarshaller();
 
       // Convert Java object to XML string
       var outputStream = new ByteArrayOutputStream();
       marshaller.marshal(ojp, outputStream);
 
       var xmlSource = new StreamSource(new ByteArrayInputStream(outputStream.toByteArray()));
 
-      transform(writer, xmlSource);
+      ojpToTrias(writer, xmlSource);
     } catch (IOException | JAXBException | TransformerException e) {
       throw new RuntimeException(e);
     }
   }
 
   static OJP triasToOjp(String trias) throws JAXBException, TransformerException {
-    var context = JAXBContext.newInstance(OJP.class);
-
     var xmlSource = new StreamSource(
       new ByteArrayInputStream(trias.getBytes(StandardCharsets.UTF_8))
     );
@@ -64,13 +63,13 @@ static OJP triasToOjp(String trias) throws JAXBException, TransformerException {
     transformer.transform(xmlSource, new StreamResult(writer));
     var transformedXml = writer.toString(StandardCharsets.UTF_8);
 
-    var unmarshaller = context.createUnmarshaller();
+    var unmarshaller = CONTEXT.createUnmarshaller();
     return (OJP) unmarshaller.unmarshal(
       new ByteArrayInputStream(transformedXml.getBytes(StandardCharsets.UTF_8))
     );
   }
 
-  static void transform(Writer writer, StreamSource xmlSource)
+  static void ojpToTrias(Writer writer, StreamSource xmlSource)
     throws IOException, TransformerException {
     var transformer = OJP_TO_TRIAS_TEMPLATE.newTransformer();
     transformer.setOutputProperty(OutputKeys.INDENT, "yes");
@@ -87,4 +86,12 @@ static Templates loadTemplate(String name) {
       throw new RuntimeException(e);
     }
   }
+
+  private static JAXBContext jaxbContext() {
+    try {
+      return JAXBContext.newInstance(OJP.class);
+    } catch (JAXBException e) {
+      throw new RuntimeException(e);
+    }
+  }
 }

application/src/ext/java/org/opentripplanner/ext/ojp/trias/TriasResource.java

@@ -107,12 +107,11 @@ private static Response error(String value) {
   }
 
   private static StreamingOutput ojpToTrias(OJP ojpOutput) {
-    StreamingOutput stream = os -> {
-      Writer writer = new BufferedWriter(new OutputStreamWriter(os));
-      OjpToTriasTransformer.transform(ojpOutput, writer);
+    return os -> {
+      Writer writer = new OutputStreamWriter(os);
+      OjpToTriasTransformer.ojpToTrias(ojpOutput, writer);
       writer.flush();
     };
-    return stream;
   }
 
   @GET