Create a class called Invoice that a hardware store might use to represent an invoice for an item sold at the store. An Invoice should include four pieces of information as instance variables

a part number (type String),

a part description (type String),

a quantity of the item being purchased (type int) and 4- a price per item (double).

Your class should have this operator that initializes the four instance variables. Provide a set and a get method for each instance variable.

In addition, provide a method named getInvoiceAmount that calculates the invoice amount (i.e., multiplies the quantity by the price per item), then returns the amount as a double value. If the quantity is not positive, it should be set to 0. If the price per item is not positive, it should be set to 0.0.

Write a test application named InvoiceTest that demonstrates class Invoices capabilities.

Hints:

The input values for the quantity and the price per item must be validated before they can be used to set the corresponding instance variables. This should be done both in the constructor and in the appropriate set methods.

The method header for getInvoiceAmount should be public double getInvoiceAmount(). Your output should appear as follows:

Solution output

Original invoice information

Part number: 1234

Description: Hammer

Quantity: 2

Price: 14.95

Invoice amount: 29.90

Updated invoice information

Part number: 001234

Description: Yellow Hammer

Quantity: 3

Price: 19.49

Invoice amount: 58.47

Original invoice information

Part number: 5678

Description: Paint Brush

Quantity: 0

Price: 0.00

Invoice amount: 0.00

Updated invoice information

Part number: 5678

Description: Paint Brush

Quantity: 3

Price: 9.49

Invoice amount: 28.47