Real life example of alerting Passengers when Flight Boarding Gate is opened by using Observer Design Pattern.
Imagine, we reach Airport and checked-in. There is enough time for Boarding Gate to be opened. And we are engaged in Duty Free shopping or engaged in our mobile on Watsapp or Facebook so deeply that we could not hear annoucement and missed flight? Ooooppps...
What if we get an sms alert for Boarding Gate Open status on our mobile phones? That's what I am going to show today by using Observer Design Pattern - When Flight Boarding Gate is opned, alert all passengers who are registered/observing on BoardingGate Status Change.
Imagine, after 30 minutes of first sms alert, some passengers still do not turn up to Boarding Gate, won't it be nice to send 2nd alert? Let's see these scenarios, it shown in Test result file.