- Add handling for the case, when the Controller could not retrieve any assignments from the database (without an error).

- Improve exception handling.
- Remove obsolete code.

src/main/java/eu/openaire/urls_worker/exceptions/FileStorageException.java

@@ -1,16 +0,0 @@
-package eu.openaire.urls_worker.exceptions;
-
-import org.springframework.http.HttpStatus;
-import org.springframework.web.bind.annotation.ResponseStatus;
-
-@ResponseStatus(HttpStatus.INTERNAL_SERVER_ERROR)
-public class FileStorageException extends RuntimeException {
-
-    public FileStorageException(String message) {
-        super(message);
-    }
-
-    public FileStorageException(String message, Throwable cause) {
-        super(message, cause);
-    }
-}

src/main/java/eu/openaire/urls_worker/plugins/PublicationsRetrieverPlugin.java

@@ -69,6 +69,7 @@ public class PublicationsRetrieverPlugin {
         PublicationsRetriever.executor = Executors.newFixedThreadPool(workerThreadsCount);
     }
 
+
     private static final List<Callable<Boolean>> callableTasks = new ArrayList<>(FileUtils.jsonBatchSize);
 
     public static void processAssignments(Long assignmentRequestCounter, Collection<Assignment> assignments) throws RuntimeException

src/main/java/eu/openaire/urls_worker/services/FileStorageService.java

@@ -1,11 +1,8 @@
 package eu.openaire.urls_worker.services;
 
-import eu.openaire.urls_worker.exceptions.FileStorageException;
 import org.slf4j.Logger;
 import org.slf4j.LoggerFactory;
 import org.springframework.beans.factory.annotation.Autowired;
-import org.springframework.core.io.Resource;
-import org.springframework.core.io.UrlResource;
 import org.springframework.stereotype.Service;
 
 import java.io.File;
@@ -39,28 +36,20 @@ public class FileStorageService {
         } catch (IOException ioe) {
             logger.error("I/O error when reading the properties file!", ioe);
             System.exit(-11);
+        } catch (Exception e) {
+            logger.error("", e);
+            System.exit(-12);
         }
     }
 
 
     @Autowired
-    public FileStorageService() throws FileStorageException {
+    public FileStorageService() {
         try {
             Files.createDirectories(assignmentsLocation);
-        } catch (Exception ex) {
-            throw new FileStorageException("Could not create the directory where the uploaded files will be stored.", ex);
-        }
-    }
-
-
-    public Resource loadFileAsResource(String fullFileName) {
-        try {
-            Path filePath = assignmentsLocation.resolve(fullFileName).normalize();
-            Resource resource = new UrlResource(filePath.toUri());
-            return resource.exists() ? resource : null;
         } catch (Exception e) {
-            logger.error("Error when loading file: " + fullFileName, e);
-            return null;
+            logger.error("Could not create the directory where the downloaded files will be stored.", e);
+            System.exit(-13);
         }
     }
 

src/main/java/eu/openaire/urls_worker/util/AssignmentsHandler.java

@@ -90,8 +90,11 @@ public class AssignmentsHandler {
         Long assignmentRequestCounter = assignmentsRequest.getAssignmentsCounter();
         List<Assignment> assignments = assignmentsRequest.getAssignments();
         if ( assignments == null ) {
-            logger.warn("The assignments were found to be null for assignmentRequestCounter = " + assignmentRequestCounter);
-            return;
+            if ( assignmentRequestCounter == -1 )
+                logger.warn("The Controller could not retrieve and assignments from the database. It will increase the attempts-number and retry in the next request.");
+            else
+                logger.warn("The assignments were found to be null for assignmentRequestCounter = " + assignmentRequestCounter);
+            return; // The Worker will just request the assignments again, immediately.
         }
 
         int assignmentsSize = assignments.size();