State

• State: Alter an object’s behavior when its state changes. Allow an object to alter its behavior when its internal state changes. The object will appear to change its class.

  

• In side of context:
  1. keep a reference of current state.
  2. delegate all action by current state.
  3. keep static const state as how many states you have

  

• In side of concreteState:
  1. manage of current state
  2. transmission of states.
  3. In all concreteState, you need to define all the actions, even some actions is meanless, just leave it empty.