Design Patterns Java™ Workbook

Chapter 7. Introducing Responsibility

The responsibility of an object is comparable to the responsibility of a representative in the Oozinoz call center. When you order fireworks from Oozinoz, the person you speak to is a representative for the company—a proxy. He or she performs foreseeable tasks, usually by delegating tasks to other systems and people. Sometimes, the representative will delegate a request to a single, central authority who will mediate the situation or will escalate problems up a chain of responsibility.

Like call center representatives, ordinary objects have the information and methods they need to operate independently. Sometimes, however, you need to centralize responsibility, diverting from the normal independent operation ...