Fixed BadSqlGrammarException when accession id set is empty

src/main/java/org/genesys2/server/persistence/domain/TraitValueRepositoryImpl.java

@@ -159,6 +159,11 @@ public class TraitValueRepositoryImpl implements TraitValueRepository {
 	@Override
 	public Map<Long, Map<Long, List<Object>>> getValues(Metadata metadata, List<Method> methods, List<Accession> accessions) {
 		final Map<Long, Map<Long, List<Object>>> accessionMetadataValues = new HashMap<Long, Map<Long, List<Object>>>();
+		
+		if (accessions.size() ==0) {
+			return accessionMetadataValues;
+		}
+		
 		final Set<Long> accessionIds = new HashSet<Long>(accessions.size());
 		for (Accession accession : accessions) {
 			// create lists