Stop Watch is a simple application that functions like a real stopwatch. You press START to start the clock running. You then press STOP to stop the clock and you can see the time that has passed. You can then press RESET to reset the time on the clock so you can start again. We have recently completed to develop its version for the Black Berry mobile telephones models.
The Visitor Design Pattern
The visitor design pattern allows us to add operations to objects that already exist without modifying their classes and without extending them.