[1758] Provide NotImplemented-throwing methods

This is for the newly introduced interface. It makes stuff compile, it
complained about pure virtual methods.

src/lib/datasrc/sqlite3_accessor.cc

@@ -1098,5 +1098,10 @@ SQLite3Accessor::findPreviousName(int zone_id, const std::string& rname)
     return (result);
 }
 
+std::string
+SQLite3Accessor::findPreviousNSEC3Hash(int, const std::string&) const {
+    isc_throw(NotImplemented, "Not implemented yet, see #1760");
+}
+
 } // end of namespace datasrc
 } // end of namespace isc

src/lib/datasrc/sqlite3_accessor.h

@@ -239,6 +239,11 @@ public:
     virtual std::string findPreviousName(int zone_id, const std::string& rname)
         const;
 
+    /// \brief Conrete implemantion of the pure virtual method of
+    /// DatabaseAccessor
+    virtual std::string findPreviousNSEC3Hash(int zone_id,
+                                              const std::string& hash) const;
+
 private:
     /// \brief Private database data
     boost::scoped_ptr<SQLite3Parameters> dbparameters_;

src/lib/datasrc/tests/database_unittest.cc

@@ -282,6 +282,11 @@ public:
         isc_throw(isc::NotImplemented,
                   "This data source doesn't support DNSSEC");
     }
+
+    virtual std::string findPreviousNSEC3Hash(int, const std::string&) const {
+        isc_throw(isc::NotImplemented,
+                  "This test database knows nothing about NSEC3 nor order");
+    }
 private:
     const std::string database_name_;