Design Problems

• Creating Objects
  • How can a class be independent of how the objects it requires are created?
  • How can a class request the objects it requires (from a factory object)
    instead of creating the objects directly?
  • How can a class delegate object creation to a factory object?
  • How can a class be configured with a factory object?
• Creating Different Object Families
  • How can families of related or dependent objects be created?
  • How can be ensured that a family of related or dependent objects
    is created and used together (consistent object families)?
  • How can an application be configured with a family of objects?
  • How can a family of objects be selected and exchanged at run-time?

Refactoring Problems

• Inflexible Code
  • How can instantiating concrete classes throughout an application (compile-time implementation dependencies) be refactored?
  • How can object creation that is distributed across an application
    be centralized? Move Creation Knowledge to Factory (68) [JK05]

Testing Problems

• Unit Testing
  • How can the objects a class requires be replaced with mock objects so that the class can be unit tested in isolation?