If the set of suitable objects, for example filenames or URLs, is proscribed or identified, develop a mapping from a set of fastened enter values (for example numeric IDs) to the actual filenames or URLs, and reject all other inputs. These methods supply an abstraction layer that facilitates encapsulation http://ricardouuvxd.getblogs.net/7050341/helping-the-others-realize-the-advantages-of-programming-homework-help