JAVA Program

Maintain customer data (binary file)

Console

Welcome to the Customer Maintenance application

COMMAND MENU

list - List all customers

add - Add a customer

upd - Update customer data

del - Delete a customer

help - Show this menu

exit - Exit this application

Enter a command: list

CUSTOMER LIST

frank46@hotmail.com Frank Jones

sarah_smith@yahoo.com Sarah Smith

Enter a command: add

Enter customer email address: test@gmail.com

Enter first name: text

Enter last name: test

text test was added to the database.

Enter a command: list

CUSTOMER LIST

frank46@hotmail.com Frank Jones

sarah_smith@yahoo.com Sarah Smith

test@gmail.com text test

Enter a command: upd

Enter customer email address of a current record: test@gmail.com

Enter first name: Waldo

Enter last name: Pepper

Enter a command: list

CUSTOMER LIST

frank46@hotmail.com Frank Jones

sarah_smith@yahoo.com Sarah Smith

test@gmail.com Waldo Pepper

Enter a command: del

Enter customer email to delete: test@gmail.com

Waldo Pepper was deleted from the database.

Enter a command: list

CUSTOMER LIST

frank46@hotmail.com Frank Jones

sarah_smith@yahoo.com Sarah Smith

Enter a command: exit

Bye.

Operation

This application begins by displaying a menu with six choices: list, add, upd, del, help, and exit.

If the user enters “list”, the application displays the customer data that’s stored in a binary file.

If the user enters “add”, the application prompts the user to enter data for a customer and saves that data to the binary file.

If the user enters “upd” the application prompts the user to enter the email address. Then, it lets the user update the first name or last name for the customer. This data is stored in the binary file.

If the user enters “del”, the application prompts the user for an email address and deletes the corresponding customer from the binary file.

If the user enters “help”, the application displays the menu again.

If the user enters “exit”, the application displays a goodbye message and exits.

Specifications

Create a class named Customer that stores data for the user’s email address, first name, and last name.

Create interfaces named CustomerReader and CustomerWriter that define the methods that will be used to read and write customer data to a customer file. In addition, create an interface named CustomerConstants that contains three constants that specify the display size of a customer’s email address (30), first name (15), and last name (15). Then, create an interface named CustomerDAO that inherits all three of these interfaces.

Create a class named CustomerRandomFile to store the data in a random-access file named customer.ran in the same directory as this class. This class should use the seek method to randomly access each customer record whenever that’s necessary. If the customers.dat file doesn’t exist, this class should create it.

Create a class named DAOFactory that contains a method named getCustomerDAO. This method should return an instance of the CustomerRandomFile class.

Create a CustomerMaintApp class that displays the prompts shown in the console output and accepts the user entries. This class should use the DAOFactory class to get a CustomerDAO object. Then, it should use the methods of the CustomerDAO object to read customer data from the file and to write customer data to the file.

Use the Validator class or a variation of it to validate the user’s entries. Non-empty strings are required for the email address, first name, and last name.

Use spaces to align the customer data in columns on the console. To do that, you can create a utility class named StringUtils with a method that adds the necessary spaces to a string to reach a specified length.