1 files changed, 7 insertions, 2 deletions
diff --git a/extractor/scorer.h b/extractor/scorer.h
index 5b328fb4..ba71a6ee 100644
--- a/extractor/scorer.h
+++ b/extractor/scorer.h
@@ -14,9 +14,14 @@ class Scorer {
  public:
   Scorer(const vector<shared_ptr<Feature> >& features);
 
-  vector<double> Score(const FeatureContext& context) const;
+  virtual ~Scorer();
 
-  vector<string> GetFeatureNames() const;
+  virtual vector<double> Score(const FeatureContext& context) const;
+
+  virtual vector<string> GetFeatureNames() const;
+
+ protected:
+  Scorer();
 
  private:
   vector<shared_ptr<Feature> > features;