You have been asked to develop a java program to simulate the operation of an elevator for a three story building. 1. Write a UML class diagram for an elevator. Include private instance variables: int CurrentFloor, bool GoingUp, and bool GoingDown. Also include methods: displayCurrentFloor(), GoUp() and GoDown(). 2. Write an elevator test program. Have the program execute the following steps using the methods in the class: Start on the first floor. Go to the second floor (dont forget to update the Boolean variable GoingUp). Go to the third floor Attempt to go to the fourth floor (Remember: there are only three floors) Go back to the second floor Go back to the first floor Be sure to call displayCurrentFloor() to notify the user which floor the elevator is on at each step