Homework 8: Elevator Simulation

In this homework, you will implement the Elevator and Floor clases for the elevator simulation project. You should use the textbook’s Stack and Queue classes in your code.

Instructions

We encourage you to work with a partner.

Task 1: Review the Starter Files

Download elevator.zip, which contains the starter files for this assignment.

Next, review the provided classes:

All the classes except the Elevator and Floor classes have been completed for you. After implementing Elevator and Floor, you can interact with the simulation by running the ManualOperator class.

Initially, there should be 14 people waiting on the 1st and 5th floors, and the elevator should be empty. Note that people are represented by their destinations, and the elevator’s position is represented by an E:

> java-introcs ManualOperator
Options: (p)rint state, (a)scend, (d)escend, (l)oad, (u)nload
> p
5   1 1 1 1 1 2 3 4 2 3 4 2 3 4 
4   
3   
2   
1 E 5 5 5 5 5 2 3 4 2 3 4 2 3 4 
Elevator:

After loading the elevator on the 1st floor, ascending a floor, then unloading on the 2nd floor, several people have made it to their destination:

> l
> a
> u
> p
5   1 1 1 1 1 2 3 4 2 3 4 2 3 4 
4   
3   
2 E 
1   4 2 3 4 
Elevator: 3 4 3 5 5 5 5 5

Note: The provided classes have dependencies on each other:

As a result, the classes must be compiled in a specific order. For example, this ordering will always work: Passenger, ElevatorException, Floor, Elevator, Building, then ManualOperator. Alternatively, you can use IntelliJ’s “Build Project” option, which will automatically compile the classes in the proper order.

Task 2: Implement Floor.java

On each floor, passengers wait in line for the elevator. The first person to arrive in line should be the first person to board the elevator when it arrives.

Refer to the Floor class’s method comments for additional implementation details.

Before implementing Floor, the building visualization won’t show the passengers:

> java-introcs ManualOperator
Options: (p)rint state, (a)scend, (d)escend, (l)oad, (u)nload
> p
5   Floor@30c7da1e
4   Floor@5b464ce8
3   Floor@57829d67
2   Floor@19dfb72a
1   Floor@17c68925
Elevator: Elevator@7e0ea639

After implementing Floor, the building visualization should show the passengers:

> java-introcs ManualOperator
Options: (p)rint state, (a)scend, (d)escend, (l)oad, (u)nload
> p
5   1 1 1 1 1 2 3 4 2 3 4 2 3 4 
4   
3   
2   
1   5 5 5 5 5 2 3 4 2 3 4 2 3 4 
Elevator: Elevator@2d6e8792

Hint: Consider whether a Stack or Queue is appropriate for keeping track of the passengers on each Floor. Use the data structures provided by the textbook authors, instead of the versions included in the Java standard library.

Hint: Override the default toString() method and depict the passengers waiting for the elevator. It will be easiest if you use the toString() method of the data structure you’re using.

Hint: Create unit tests for Floor.

Task 3: Implement Elevator.java

The elevator should initially start on the 1st floor, and can travel to any of the floors in the building by moving one floor at a time. If the elevator operator tries to travel to a non-existent floor, an ElevatorException should be raised.

The elevator should have a limited capacity for passengers. The elevator should be filled from back to front, so that the first person to enter the elevator should be the last person to exit the elevator when they disembark.

Refer to the Elevator class’s method comments for additional implementation details.

After implementing Elevator, test that you can use the ManualOperator class to transport all the passengers to their destinations.

Hint: Consider whether a Stack or Queue is appropriate for keeping track of the passengers in the Elevator. Use the data structures provided by the textbook authors, instead of the versions included in the Java standard library.

Hint: Override the default toString() method and depict the passengers riding in the elevator. It will be easiest if you use the toString() method of the data structure you’re using.

Hint: Create unit tests for Elevator.

Submit

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Learning Goals