- Optimize the json-conversion of the "BulkImportReport".

- Code polishing.

src/main/java/eu/openaire/urls_controller/controllers/UrlsController.java

@@ -82,7 +82,7 @@ public class UrlsController {
             return ResponseEntity.status(HttpStatus.INTERNAL_SERVER_ERROR).build();
         }
         String remoteAddr = request.getHeader("X-FORWARDED-FOR");
-        if ( (remoteAddr == null) || "".equals(remoteAddr) )
+        if ( (remoteAddr == null) || remoteAddr.isEmpty() )
             remoteAddr = request.getRemoteAddr();
 
         WorkerInfo workerInfo = workersInfoMap.get(workerId);

src/main/java/eu/openaire/urls_controller/models/BulkImportReport.java

@@ -15,6 +15,8 @@ import java.util.Map;
 @JsonInclude(JsonInclude.Include.NON_NULL)
 public class BulkImportReport {
 
+    private static final Gson gson = new Gson();    // This is "transient" by default. It won't be included in any json object.
+
     @JsonProperty
     private String provenance;
 
@@ -48,7 +50,7 @@ public class BulkImportReport {
     {
         //Convert the LinkedHashMultiMap<String, String> to Map<String, Collection<String>>, since Gson cannot serialize Multimaps.
         eventsMap = eventsMultimap.asMap();
-        return new Gson().toJson(this);
+        return gson.toJson(this);
     }
 
     public String getProvenance() {

src/main/java/eu/openaire/urls_controller/util/FileUtils.java

@@ -331,9 +331,8 @@ public class FileUtils {
         baseUrl += batchNum + "/";
         String requestUrl = getRequestUrlForBatch(baseUrl, fileNamesForCurBatch);
         //logger.debug("Going to request the batch_" + batchNum + " (out of " + totalBatches + ") with " + fileNamesForCurBatch.size() + " fullTexts, of assignments_" + assignmentsBatchCounter + " from the Worker with ID \"" + workerId + "\" and baseRequestUrl: " + baseUrl + "[fileNames]");
-        HttpURLConnection conn = null;
         try {
-            conn = (HttpURLConnection) new URL(requestUrl).openConnection();
+            HttpURLConnection conn = (HttpURLConnection) new URL(requestUrl).openConnection();
             conn.setRequestMethod("GET");
             conn.setRequestProperty("User-Agent", "UrlsController");
             conn.connect();
@@ -346,7 +345,8 @@ public class FileUtils {
                 if ( (statusCode >= 500) && (statusCode <= 599) )
                     throw new RuntimeException();   // Throw an exception to indicate that the Worker has problems and all remaining batches will fail as well.
                 return null;
-            }
+            } else
+                return conn;
         } catch (RuntimeException re) {
             throw re;
         } catch (Exception e) {
@@ -358,7 +358,6 @@ public class FileUtils {
             }
             return null;
         }
-        return conn;
     }