Emp.JavaÂ
public class Emp
{
           private String firstName;
           private String lastName;
           private Date birthDate;
           private Date hireDate;
          Â
           //constructor to initialize name, birth date, and hire date
           public Emp (String first, String last, Date dateOfBirth, Date dateOfHire)
           {
                       firstName = first;
                       lastName = last;
                       birthDate = dateOfBirth;
                       hireDate = dateOfHire;
           }
          Â
           //convert Emp to String format
           public String toString()
           {
                       return String.format(“%s, %s Hired: %s Birthday: %s”,
                                   lastName, firstName, hireDate, birthDate);
           }
}
  Date.JavaÂ
//Date class declaration
public class Date
{
           private int month;         //1-12
           private int day; //1-31 based on month
           private int year; //any year
          Â
           //constructor: call checkMonth to confirm proper value for month
           //call checkDay to confirm proper value for day
           public Date(int theMonth, int theDay, int theYear)
           {
                       month = checkMonth(theMonth);         //validate month
                       year = theYear;                                   //could validate year
                       day = checkDay(theDay);                    //validate day
                       System.out.printf(“Date object constructor for date %s\n”, this);
           }
          Â
Â
           //utility method to confirm proper month value
           private int checkMonth (int testMonth)
           {
                       if (testMonth>0 && testMonth <=12)  //validate month
                                   return testMonth;
                                   else                                                    //month is invalid
                                   {
                                   System.out.printf(“Invalid month (%d) set to 1.”, testMonth);
                                   return 1;          //maintain object in consistent state
                                   }
           }
          Â
           //utility method to confirm proper day value based on month and year
           private int checkDay (int testDay)
           {        Â
                       //0 is ignored since daysPerMonth[0]=0 represents 0 months
                       //Month starts on the 2nd element after 0 (from 1-12)
                       int daysPerMonth[]={0,31,28,31,30,31,30,31,31,30,31,30,31};
                      Â
                       //check if day in range for month
                       if (testDay >= 1 && testDay <= daysPerMonth[month])
                                   return testDay;
                                  Â
                       //check for leap year
                       if (month == 2 && testDay == 29 && (year % 400==0 ||
                                   (year % 4 == 0 && year % 100 != 0)))
                                   return testDay;
                                  Â
                       System.out.printf(“Invalid day (%d) set to 1.”, testDay);
                       return 1;          //maintain object in consistent state
           }
          Â
           //return a String of the form month/day/year
           //automatically invoked even without calling this method
           public String toString()
           {
                       return String.format(“%d/%d/%d”, month, day, year);
           }
}
      EmpTest.JavaÂ
//composition demonstration
public class EmpTest
{
           public static void main (String args[])
           {
                       Date birth = new Date(7,0,1980);
                       Date hire = new Date(9,5,2007);
          Â
                       Emp employee = new Emp(“Ana”, “Santos”, birth, hire);
                      Â
                       System.out.println(employee);
           }
}
UST-ICS 