@Override
 public final void setPreferenceInferrer(PreferenceInferrer inferrer) {
   if (inferrer == null) {
     throw new IllegalArgumentException("inferrer is null");
   }
   refreshHelper.addDependency(inferrer);
   refreshHelper.removeDependency(this.inferrer);
   this.inferrer = inferrer;
 }
 public final void setPrefTransform(PreferenceTransform prefTransform) {
   refreshHelper.addDependency(prefTransform);
   refreshHelper.removeDependency(this.prefTransform);
   this.prefTransform = prefTransform;
 }
 public final void setSimilarityTransform(SimilarityTransform similarityTransform) {
   refreshHelper.addDependency(similarityTransform);
   refreshHelper.removeDependency(this.similarityTransform);
   this.similarityTransform = similarityTransform;
 }