Java OOP - Method Overloading and Static Methods

Introduction

In this exercise, you will work on a LemonadeStand application that simulates a lemonade stand. The menu system and main application is already implemented in the Main class, but the LemonadeStand class and the Lemonade class both need some work to support some additional functionality.

Let's get started!

Familiarize Yourself with the Code

Before you begin, take a moment to familiarize yourself with the code that is already implemented. Open the Main class in the src/main/java/org/example directory and take a look at the Main class. You will see that this class implements a simple menu system that allows the user to interact with the LemonadeStand application.

Look through the menu code to see what options are available to the user.

You will also see that the LemonadeStand class is already implemented, but has a commented section that indicates that we will need to add an overloaded implementation of the sellLemonade method.

Finally, you will see that the Lemonade class is already implemented, but has a commented section that indicates that we will need to add a static method allowing us to create a new Lemonade object by mixing two other Lemonade objects.

Adding sellLemonade Method Overload

The LemonadeStand class has a method called sellLemonade that allows the user to sell lemonade. This method is already implemented for selling a normal lemonade, but we need to add an overloaded version of this method that allows the user to sell a special lemonade where the user has selected the amount of lemons, sugar, and ice to use.

Remmember that method overloading allows us to define a new method with the same name as an existing method, but with different parameters. In this case, we want to add a new method called sellLemonade that takes three parameters (in this order!):

Parameter	Type	Description
lemons	int	The number of lemons to use in the lemonade
sugar	int	The amount of sugar to use in the lemonade
ice	int	The amount of ice to use in the lemonade

There is a clue in the comments about how to implement the body of this method. All that we'll need to do is copy the existing implementation of the sellLemonade method and modify the first line to create a new Lemonade object using the parameters provided instead of calling the default Lemonade constructor.

Adding a Static Method to the Lemonade Class

The Lemonade class has a comment at the bottom indicating that we need to add a static method called mix to the Lemonade class that allows us to create a new Lemonadeobject by mixing two other Lemonade objects.

The mix method should take two parameters (in this order!):

Parameter	Type	Description
lemonade1	Lemonade	The first Lemonade object to mix
lemonade2	Lemonade	The second Lemonade object to mix

To implement this method, we should set up variables to hold the combined amounts of lemons, sugar, and ice from the two Lemonade objects, and then create a new Lemonade object using these combined values to call the Lemonade constructor that takes three parameters.

Additional Challenge

If you finish and want an additional challenge, try adding yet another overloaded version of the sellLemonade method that creates a default Lemonade object and sells it as the normal one does, but inlcudes a parameter specifying a percentage discount to apply to the price of the lemonade.

You will also need to modify the Main class to allow the user to select to sell a discounted lemonade and provide the discount percentage.

This is a particularly challenging exercise, that will require you to comprehensively understand the existing code and how the LemonadeStand class works.

If you open the LemonadeStandTest class in the src/test/java/org/example directory, you will see that there is a commented out test at the bottom that you can use to verify your solution. You will need to comment out this test by removing the starting /* and ending */ lines, and then run the tests as usual to verify your solution.