Static Class Structure

• Client
  • Refers to the Subject interface.
• Subject
  • Defines a common interface for RealSubject and Proxy objects.
• RealSubject
  • Defines objects that get substituted.
• Proxy
  • Maintains a reference to a RealSubject object (realSubject).
  • Implements additional functionality to control the access to this RealSubject object.
  • Implements the Subject interface so that it can act as substitute whenever a Subject object is expected.

Dynamic Object Collaboration

• In this sample scenario, a Client object works through a Proxy object that controls the access to a RealSubject object.
• The Client object calls operation() on the Proxy object.
• The Proxy may perform additional functionality and forwards the request to the RealSubject object, which performs the request.
• See also Sample Code / Example 1.