- Improve handling of already renamed workerReport-files, which relate to failed workerReports in the 1st try.

- Add check for workerReport-files, which may have been deleted before their time, due to an error.

src/main/java/eu/openaire/urls_controller/services/UrlsServiceImpl.java

@@ -517,6 +517,17 @@ public class UrlsServiceImpl implements UrlsService {
         // Rename the worker-report to indicate success or failure.
         String workerReportBaseName = this.workerReportsDirPath + File.separator + workerId + File.separator + workerId + "_assignments_" + assignmentRequestCounter + "_report";
         File workerReport = new File(workerReportBaseName + ".json");
+
+        // Check if the workerReport does not exist under this name, as it may have been renamed previously to "failed" and now is the 2nd try.
+        if ( ! workerReport.isFile() ) {
+            // Then this is the 2nd try and the report has already been renamed to "failed" the 1st time.
+            workerReport = new File(workerReportBaseName + "_failed.json");
+            if ( ! workerReport.isFile() ) {    // In this case, an error exists, since this file was deleted before its time.
+                logger.error("The workerReport file \""  + workerReport.getAbsolutePath() + "\" does not exist!");
+                // TODO - How to handle it? This report may be either successful or failed but the file was deleted.
+            }
+        }
+
         File renamedWorkerReport = new File(workerReportBaseName + ((errorMsg == null) ? "_successful.json" : "_failed.json"));
         boolean wasWorkerReportRenamed = true;
         try {