Front Controller

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

Front Controller

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

Real world examples

• Apache Struts

Credits

• J2EE Design Patterns
• Presentation Tier Patterns
• Patterns of Enterprise Application Architecture
• J2EE Design Patterns