Complex sentence: The non-virtual interface pattern (NVI) design pattern that controls how methods in a base class are overridden, which include public, non-virtual members that may be called by clients, and overridable methods with core functionality.
Split into simpler sentences: The non-virtual interface design pattern (NVI) controls how methods in a base class are overridden. Such methods are public, non-virtual members that may be called by clients and overridable methods with core functionality.