+ /**
+ * Method used for checking if the given user value understandable for
+ * parameter.
+ *
+ * @return true if passed value is understandable by current Parameter.
+ * False otherwise.
+ */
+ virtual bool understand(const std::string & ) = 0;
+
+ /**
+ * Indicates if current Parameter is required
+ *
+ * @return false, as all Parameters are non-required by default. If you
+ * want to make Parameter as required, wrap it using Required class
+ */
+ virtual bool isRequired() {
+ return false;
+ };
+
+ /**
+ * Indicates if current Parameter has been already used
+ *
+ * @return true if current Parameter has been already used. False otherwise.
+ */
+ virtual bool isUsed() {
+ return used;