Labs

We will change the Car class to use better encapsulation, and then fix a test class that uses Car. Finally, we will create a class that stores Car objects.

1. Copy the Car class from com.example.encapsulation.reference into com.example.encapsulation.labs; you must create the package if you have not already.

2. Change the Car class's fields to have private visibility.

3. Add getters and setters for the fields.
4. Add a constructor with parameters for all five fields.
5. Add a no-arg constructor.

6. Change the name of the method getCarData to toString (because it is not a getter).

7. Copy CarTester from com.example.encapsulation.reference into com.example.encapsulation.labs.

8. The class is broken. Change it to use getters and setters.

9. Create a class called ParkingLot. Its job is to hold an array of cars. The class will have:

10. A field for a Car[]. This field is of course private.
11. private static int MAX_CARS = 100;.
12. A no-arg constructor. In this constructor, initialize the Car[] to have space for 100 Car references.

13. Two methods.

    1. void addCar(Car car). This adds a Car to the array. (How will you decide the next available array location? You probably need to keep track of the number of cars in the array.)

       Users outside the package should be able to use this method.

    2. Car[] getCars(). This returns a reference to the Car[] in ParkingLot.

       Users outside the package should be able to use this method.

14. Create a class called ParkingLotTester. This class will have a main method.

15. Create a ParkingLot instance.

16. Call getCars and verify that an array of the correct length is returned (by printing its length to the screen).
17. Iterate through the array to verify that it contains null values.
18. Create several Car instances and add them to the ParkingLot.
19. Call getCars to get the array of Cars.
20. Verify that getCars still returns an array of the same length.
21. Iterate through the array and have each Car display itself. (Be careful of attempting to call a method on a null reference.)

Stretch Goals

Car[] getCars(). Return an array containing all Cars in the ParkingLot. It does not just return the private reference. It will instead return a different array containing all Cars in the ParkingLot; the array does not have any null elements.

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