Refactors how "External Resources" are saved on Dataset.

dmp-backend/data/src/main/java/eu/eudat/data/entities/Dataset.java

@@ -281,20 +281,41 @@ public class Dataset implements DataEntity<Dataset, UUID> {
 		this.setLabel(entity.getLabel());
 		this.setProperties(entity.getProperties());
 
-		this.getDatasetDataRepositories().removeAll(this.getDatasetDataRepositories());
-		if (entity.getDatasetDataRepositories() != null)
-			this.getDatasetDataRepositories().addAll(entity.getDatasetDataRepositories());
+		if (entity.getDatasetDataRepositories() == null || entity.getDatasetDataRepositories().size() < 1) {
+			if (this.getDatasetDataRepositories() != null) this.getDatasetDataRepositories().removeAll(this.getDatasetDataRepositories());
+		} else {
+			if (this.getDatasetDataRepositories() != null) {
+				this.getDatasetDataRepositories().removeAll(this.getDatasetDataRepositories());
+			} else {
+				this.setDatasetDataRepositories(new HashSet<>());
+			}
+			this.getDatasetDataRepositories().addAll(entity.getDatasetDataRepositories().stream().peek(item -> item.setDataset(this)).collect(Collectors.toList()));
+		}
+
+		if (entity.getDatasetExternalDatasets() == null || entity.getDatasetExternalDatasets().size() < 1) {
+			if (this.getDatasetExternalDatasets() != null) this.getDatasetExternalDatasets().removeAll(this.getDatasetExternalDatasets());
+		} else {
+			if (this.getDatasetExternalDatasets() != null) {
+				this.getDatasetExternalDatasets().removeAll(this.getDatasetExternalDatasets());
+			} else {
+				this.setDatasetExternalDatasets(new HashSet<>());
+			}
+			this.getDatasetExternalDatasets().addAll(entity.getDatasetExternalDatasets().stream().peek(item -> item.setDataset(this)).collect(Collectors.toList()));
+		}
 
-		this.getDatasetExternalDatasets().removeAll(this.getDatasetExternalDatasets());
-		if (entity.getDatasetExternalDatasets() != null)
-			this.getDatasetExternalDatasets().addAll(entity.getDatasetExternalDatasets());
+		if (entity.getServices() == null || entity.getServices().size() < 1) {
+			if (this.getServices() != null) this.getServices().removeAll(this.getServices());
+		} else {
+			if (this.getServices() != null) {
+				this.getServices().removeAll(this.getServices());
+			} else {
+				this.setServices(new HashSet<>());
+			}
+			this.getServices().addAll(entity.getServices().stream().peek(item -> item.setDataset(this)).collect(Collectors.toList()));
+		}
 
 		this.setRegistries(entity.getRegistries());
 
-		this.getServices().removeAll(this.getServices());
-		if (entity.getServices() != null)
-			this.getServices().addAll(entity.getServices());
-
 		this.setDmp(entity.getDmp());
 		this.setStatus(entity.getStatus());
 		this.setProfile(entity.getProfile());