Design Problems

• Defining State-Specific Behavior
  • How can an object alter its behavior when its internal state changes?
  • How can state-specific behavior be defined
    so that new states can be added and the behavior of existing states can be changed independently?
  • How can conditional statements that depend on an object's internal state be avoided?

Refactoring Problems

• Complicated Code
  • How can conditional statements that depend on an object's internal state be eliminated? Replace State-Altering Conditionals with State (166) [JK05]