Design Problems

• Controlling Access to Objects
  • How can the access to an object be controlled?
  • How can additional functionality be provided when accessing an object?

• Common Kinds of Proxies
  • A protection proxy acts as placeholder for sensitive objects
    to check that clients have the required access rights.
  • A virtual proxy acts as placeholder for expensive objects
    to defer their creation until they are actually needed.
  • A remote proxy acts as placeholder for remote objects
    to hide complex network communication details from clients.