/** @version 1.10 17 Aug 1998 @author Cay Horstmann */ import java.io.*; import java.util.*; class ObjectFileTest { public static void main(String[] args) { Manager boss = new Manager("Carl Cracker", 80000, 1987, 12, 15); boss.setBonus(5000); Employee[] staff = new Employee[3]; staff[0] = boss; staff[1] = new Employee("Harry Hacker", 50000, 1989, 10, 1); staff[2] = new Employee("Tony Tester", 40000, 1990, 3, 15); try { // save all employee records to the file employee.dat ObjectOutputStream out = new ObjectOutputStream(new FileOutputStream("employee.dat")); out.writeObject(staff); out.close(); // retrieve all records into a new array ObjectInputStream in = new ObjectInputStream(new FileInputStream("employee.dat")); Employee[] newStaff = (Employee[])in.readObject(); in.close(); // print the newly read employee records for (int i = 0; i < newStaff.length; i++) System.out.println(newStaff[i]); } catch (Exception e) { e.printStackTrace(); } } } class Employee implements Serializable { public Employee() {} public Employee(String n, double s, int year, int month, int day) { name = n; salary = s; GregorianCalendar calendar = new GregorianCalendar(year, month - 1, day); // GregorianCalendar uses 0 for January hireDay = calendar.getTime(); } public String getName() { return name; } public double getSalary() { return salary; } public Date getHireDay() { return hireDay; } public void raiseSalary(double byPercent) { double raise = salary * byPercent / 100; salary += raise; } public String toString() { return getClass().getName() + "[name=" + name + ",salary=" + salary + ",hireDay=" + hireDay + "]"; } private String name; private double salary; private Date hireDay; } class Manager extends Employee { /** @param n the employee's name @param s the salary @param year the hire year @param month the hire month @param day the hire day */ public Manager(String n, double s, int year, int month, int day) { super(n, s, year, month, day); bonus = 0; } public double getSalary() { double baseSalary = super.getSalary(); return baseSalary + bonus; } public void setBonus(double b) { bonus = b; } public String toString() { return super.toString() + "[bonus=" + bonus + "]"; } private double bonus; }