+ public static Optional<XmlFileStorageAdapter> getInstance() {
+ return Optional.fromNullable(instance);
+ }
+
+ public Set<String> getPersistedFeatures() {
+ return lastCfgSnapshotCache == null ? Collections.<String>emptySet() : lastCfgSnapshotCache.getFeatures();
+ }
+
+ public void setFeaturesService(final FeatureListProvider featuresService) {
+ this.featuresService = Optional.of(featuresService);
+ }
+