- if (keyDefinition != null) {
- for (final QName keyDef : keyDefinition) {
- listKeys.add(keyDef.getLocalName());
- }
+ switch (keyDefinition.size()) {
+ case 0:
+ return Collections.emptyList();
+ case 1:
+ return Collections.singletonList(keyDefinition.get(0).getLocalName());
+ default:
+ final List<String> listKeys = new ArrayList<>(keyDefinition.size());
+ for (final QName keyDef : keyDefinition) {
+ listKeys.add(keyDef.getLocalName());
+ }
+ return listKeys;