Java's Object Orientation, I/O

CS 161 - Java

Assignment for next time

Reading

• Chapter 7 - Event Driven Programming Using the AWT

Homework

Goal:

• Add input/output capabilities to one of your classes;

• read data, process it, and produce some results calculated from the input using multiple classes.

Purpose:

• To access data from an external source,

• To learn how to instruct the computer to process it,

• How to break data into pieces associated with objects.

• Learn about I/O principles;

• Building more complex programs by combining simple pieces.

Using the Employee class you wrote for the second assignment (or using the Employee class on the next page), create a new class called Company which will have the following methods related to calculating a simple payroll for company employees.

• public Employee inputEmployeeRecord()
  

  This instance method should read information for a single Employee from an input source and create a new Employee object, returning the single Employee as the result.

  Employee records being read from an input file will consist of a name on one line, and an annual salary figure on the next line:

  You might want to make use of the InputInterpreter class.

• public void inputFile(String filename)
  

  This method will open the file specified by the filename argument and use the inputEmployeeRecord method to read and create Employee objects. The resulting Employees should be stored in an instance array of Employees for later processing.

  Use the file of employee input data that is given on the next page.

  For input, you may use either SavitchIn, InputInterpreter, or your own input/output and data interpretation capabilities.

  If you use SavitchIn (which only reads from System.in (normally the keyboard), you can use input re-direction on both Windows and Unix:

   java MyClass <employees.dat
  

  though you'll have to figure out some way of handling how many employees are being entered or detecting the end of input. You may find it easier to use the InputInterpreter class. You must use the records provided. If you modify the input file in any way, please submit your modified input file too.

• public void processPayroll()
  

  This method should access each Employee object in the array that you populated in the inputFile() method. Use the Employee class' getSalary() method to access the employee's annual salary. Use the Employee class' getName() method to access the Employee's name. Calculate a biweekly salary amount (annual salary divided by 26 pay periods) and then report as output the employee's name and biweekly salary.

• public static void main(String[] args)
  

  Have your Company class's main method make an instance of the Company class, then call inputFile with the name of the employee data file on that Company instance and finally call the Company instance's processPayroll() method.

Be sure to document your programs.

Hand in listings of your class source files, and a transcript of its execution.

jwd