Observer pattern: Draw a class diagram for a weatherStation which can sense temperature and send out notification to public. If a user register for the weatherStation.com, he/she will be notified by the weatherStation and he/she can also know the temperature. a) Draw a class diagram using observer pattern. b) Draw a sequence diagram (bonus 5 pts). c) Write a pseudo class in java. You can ignore the detail implementation but your code should indicate the relations. Observer pattern: Draw a class diagram for a weatherStation which can sense temperature and send out notification to public. If a user register for the weatherStation.com, he/she will be notified by the weatherStation and he/she can also know the temperature. a) Draw a class diagram using observer pattern. b) Draw a sequence diagram (bonus 5 pts). c) Write a pseudo class in java. You can ignore the detail implementation but your code should indicate the relations