Basic HTML version of Foils prepared Sept 23 97
| If the user select "Check All" mode, all visualization windows update their states according to an event. If the event(click buttons, choose menu item...) occurs, all of the windows would be updated to reflect this event. |
| The Observer pattern has two participants, Observers and Observables and defines a one to many relationship between them. An Observerable object contains a list of its Observers. When the Observable's state changes it notifies its Observers so that they are updated automatically. This one-to-many relationship of objects is defined by the Observer design pattern. |