The state of the class takes on both active and passive qualities.
A passive state is simply the current status of an objects attributes. For example: Consider a GPS app. Your position, direction, etc are just attributes of your class, and thus the passive state.
An active state is the status of an object that is undergoing a continuous transformation. The book mentions a game player object which is resting, healing, moving, etc.
An event (sometimes called a trigger) occurs when something happens to cause an object to move from one active state to another.
State Diagrams
A state diagram is used to show how an object can move between different states. In some cases, you will continue to work in the state you are in. For example, in the book, you have a keypad to enter your password to modify the system. You can compare your password entered against the stored password several times until you get to either an unlocked or locked out phase.
Between states, there is text that describes what is occurring to make you move from one state to the next.
Sequence Diagrams
A sequence diagram shows the steps, or sequence, in which a process occurs. It lists each item on a separate column, with each step given it’s own row. Arrows can easily show from what step one item occurs to another.
State Representations was originally found on Access 2 Learn
