Fixed issue when creating new Datasets

dmp-backend/elastic/src/main/java/eu/eudat/elastic/repository/DatasetRepository.java

@@ -49,14 +49,19 @@ public class DatasetRepository extends ElasticRepository<Dataset, DatasetCriteri
             XContentBuilder builder = XContentFactory.jsonBuilder();
             Dmp dmp = this.dmpRepository.findDocument(entity.getDmp().toString());
             boolean found = false;
-            for(int i = 0; i < dmp.getDatasets().size(); i++) {
+            if (dmp.getDatasets() != null && !dmp.getDatasets().isEmpty()) {
-                if (dmp.getDatasets().get(i).getId().equals(entity.getId())) {
+                for (int i = 0; i < dmp.getDatasets().size(); i++) {
-                    dmp.getDatasets().set(i, entity);
+                    if (dmp.getDatasets().get(i).getId().equals(entity.getId())) {
-                    found = true;
+                        dmp.getDatasets().set(i, entity);
-                    break;
+                        found = true;
+                        break;
+                    }
                 }
             }
             if (!found) {
+                if (dmp.getDatasets() == null) {
+                    dmp.setDatasets(new ArrayList<>());
+                }
                 dmp.getDatasets().add(entity);
             }
             IndexRequest request = new IndexRequest("dmps").id(dmp.getId().toString()).source(dmp.toElasticEntity(builder));//new IndexRequest("datasets", "doc", entity.getId()).source(entity.toElasticEntity(builder));