A real-life example

The Builder design pattern is used in fast-food restaurants. The same procedure is always used to prepare a burger and the packaging (box and paper bag), even if there are many different kinds of burgers (classic, cheeseburger, and more) and different packages (small-sized box, medium-sized box, and so forth). The difference between a classic burger and a cheeseburger is in the representation, and not in the construction procedure. The director is the cashier who gives instructions about what needs to be prepared to the crew, and the builder is the person from the crew that takes care of the specific order. The following figure provided by www.sourcemaking.com shows a Unified Modeling Language (UML) sequence diagram of the communication that takes place between the customer (client), the cashier (director), and the crew (builder) when a kid's menu is ordered [j.mp/builderpat].