Front Controller
Less than 1 minute
Intent
Introduce a common handler for all requests for a web site. This
 way we can encapsulate common functionality such as security,
 internationalization, routing and logging in a single place.
Class diagram

Applicability
Use the Front Controller pattern when
- you want to encapsulate common request handling functionality in single place
 - you want to implements dynamic request handling i.e. change routing without modifying code
 - make web server configuration portable, you only need to register the handler web server specific way