fix more design

1 files changed, 3 insertions, 8 deletions

diff --git a/NullTileBehavior.h b/NullTileBehavior.h
index 72aa196..004b256 100644
--- a/NullTileBehavior.h
+++ b/NullTileBehavior.h
@@ -3,15 +3,10 @@
 #include "TileBehavior.h"
 
 class NullTileBehavior : public TileBehavior {
+	friend class TileBehaviorFactory;
+	using TileBehavior::TileBehavior;
+
 public:
 	virtual void update(Tile &);
-	virtual std::unique_ptr<TileBehavior> clone(Museum &);
-
-	static constexpr const char * type = "";
-
-private:
-	using TileBehavior::TileBehavior;
-	static NullTileBehavior instance;
-	NullTileBehavior() = default;
 };