Objectifying Coffee Vending Machine¶

Goal¶

As we did in MealOrder, you will pull out the "ingredients", i.e., the size of coffee and the creamer, into separate classes.

For reference, the MealOrder, Burger, etc. classes are here.

Pull out the size and creamer aspects of the coffee into their own classes.
First extract the size and creamer tests into their own classes, e.g., SizeTest and CreamerTest.
Then extract the code into the classes.
Make sure those tests work before moving on..
Change CoffeeOrder so that it has references to the Size and Creamer objects.
Ask yourself how CoffeeOrder knows how to create the appropriate Size and Creamer objects.
Change the price() method on CoffeeOrder so that it delegates the price to the size and creamer objects.
Make sure all of your tests continue to pass!

Do not continue unless all tests pass.

Create a "base" class, CoffeeItem that has a price method:

  public int price() {
    return 0;
  }

Change Size and Creamer so that they inherit from the base class and override the price() method.
All tests should still pass!

Change CoffeeOrder to have a List of CoffeeItem instead of references to size and creamer.
Update the price() method in CoffeeOrder so that it sums over all of the items using a for loop.

Java's For Each Loop

You can find more info about this "enhanced" form of the for loop here: https://blogs.oracle.com/corejavatechtips/using-enhanced-for-loops-with-your-classes
Are tests still passing?

Once you've completed the above steps, check in with the instructor to review your code.

Add a new item, Sweetener, that has these options:
- None: 0 cents
- Sugar: 10 cents
- Splenda: 15 cents
Make sure you have tests that try out a full coffee order with and without sugar.

Add a new size of coffee that is "XL" (extra large) and costs $3.
- Think about what you need to change.
- Make sure tests continue to pass.

Create a new display() method on CoffeeOrder that displays to the screen (using System.out.println()) the coffee order. For example:
```
Size: Medium
Creamer: Milk
Sweetener: Sugar
Price: 185
```
Think about what is in common across the different types of CoffeeItems -- how is this similar to price()?

In the main method in App, create a variety of CoffeeOrders and have them printed out.

Once you've completed the above steps, check in with the instructor to review your code.

The next steps are optional...