1. List as many implementations of the observer pattern as you can that you would i nd in the
2. Create an example that uses notifyObserver = Reception.IF_EXISTS as an argument to the
3. Use the observers transitional sensitivity to monitor the progress of a transaction and log the
result of the transaction (success or failure).
1. Design Patterns: Elements of Reusable Object‐Oriented Software (Addison‐Wesley, 1994):
Erich Gamma, Richard Helm, Ralph Johnson, John Vlissides.
2. Head First Design Patterns (O'Reilly, 2004): Eric Freeman, Elisabeth Robson, Bert Bates,
3. A small hardware board for maker projects: http://www.arduino.cc.
4. Abraham Maslow (1908-1970) American Psychologist.