Lab #7 (Exercise 8-1)

Create and work with interfaces

Due Date: Monday of Week 3
10 points

In this lab, you'll create and implement the DepartmentConstants interface presented in this chapter. You'll also create and implement an interface named Displayable that's similar to the Printable interface.

Create the interfaces

Add an interface named DepartmentConstants that contains the three constants. Compile the interface.

Add an interface named Displayable. This interface should contain a single method named getDisplayText that returns a String. Compile this interface.

Implement the interfaces

Edit the Product class so it implements the Displayable interface. The getDisplayText method in this class should format a string that can be used to display the product information. When you're done, compile this class.

import java.text.NumberFormat;

public class Product
{
	private String code;
	private String description;
	private double price;

	public Product()
	{
		this.code = "";
		this.description = "";
		this.price = 0;
	}

	public Product(String code, String description, double price)
	{
		this.code = code;
		this.description = description;
		this.price = price;
	}

	public void setCode(String code)
	{
		this.code = code;
	}

	public String getCode(){
		return code;
	}

	public void setDescription(String description)
	{
		this.description = description;
	}

	public String getDescription()
	{
		return description;
	}

	public void setPrice(double price)
	{
		this.price = price;
	}

	public double getPrice()
	{
		return price;
	}

	public String getFormattedPrice()
	{
		NumberFormat currency = NumberFormat.getCurrencyInstance();
		return currency.format(price);
	}

}

Edit the Employee class so it implements the DepartmentConstants and Displayable interfaces. The getDisplayText method in this class should work like the one in the Product class, and it should use the constants in the DepartmentConstants interface to include the department name in the return value. When you're done, compile this class.

Use the classes that implement the interfaces

Display the DisplayableTestApp class.

Add code to this class that creates an Employee object, assigns it to a Displayable variable, and displays the information in the Employee object at the console. To get the information for an employee, you'll need to use the getDisplayText method of the Displayable interface.

Compile and run the application to make sure that it displays the employee information.

Repeat steps 6 and 7 for a Product object.

Include in your program the following comments:

Name of program
Team's name with all the names of the members (e.g. Team A: John Doe, Jane Smith, etc.)
Current Date
Computer system and compiler you are using
Brief description of the program

Compile and run the Java program.

When you are ready, upload the java program by clicking the link below:

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