Dates, Multiple Constructors Example

• This class prints informational messages based on the due dates compared to the current date.
• The quarter can either be calculated by the current date, or stated as a command line argument.

// import java.util so that we can use GregorianCalendar and Date
import java.util.*;

/**
 * class DueDates
 *
 * A class used to demonstrate multiple constructors, GregorianCalendar, and
 * Date objects.
 *
 * @author  jonesbr@email.uc.edu
 * @version 1.0
 */
public class DueDates {

    /**
     * The default constructor.  Assumes the current quarter is Winter 02.
     */
    public DueDates() {
        // Figure out the proper quarter intellegently, by looking at the current month.
        GregorianCalendar gcToday = new GregorianCalendar();
        // Get the month and year for comparison purposes.
        int month = gcToday.get(Calendar.MONTH);
        int year = gcToday.get(Calendar.YEAR);
        // See where we are.
        if (month >= 0 && month <= 2 && year == 2002) {
            // initialize winter quarter dates.
            System.out.println("Initializing Winter 2002");
            initializeWinter02();
        } else if (month >= 8 && month <= 11) {
            // initialize autumn quarter dates.
            System.out.println("Initializing Autumn 2002");
            initializeAutumn02();
        } else {
            // Unable to compute.  Print an informational message.
            System.out.println("DueDates is not currently set up to use the current date.");
            System.out.print("Please enter a quarter and year in the command");
            System.out.println("arguments when starting DueDates.");
        }
 
 
    }
 
    /**
     * This constructor assigns the quarter from the command line arguments.
     *
     */
 
    public DueDates(String quarter) {
 
        // initialize to the appropriate quarter based on the command line arguments.
        if (quarter.equals("Winter02")) {
            initializeWinter02();
        } else if (quarter.equals("Autumn02")) {
            initializeAutumn02();
        } else {
            System.out.println("Invalid command line arguments.  Please try again.");
        }
    }

    /**
     * initializeWinter02
     *
     * A method to initialize due dates for Winter Quarter 2002
     *
     * @return void
     */
 
    public void initializeWinter02(){
        // Jan 30 Quiz
        // Feb 13 Proj 1
        // Feb 20 Midterm
        // For each date, instantiate the GregorianCalendar and get the time.
        // We can do this all in one line, or break it up into multiple lines.
        Date quiz = (new GregorianCalendar(2002, 0, 30)).getTime();
        Date projectOne = (new GregorianCalendar(2002, 1, 13)).getTime();
        Date midterm = (new GregorianCalendar(2002, 1, 20)).getTime();
        sendAlert(quiz, projectOne, midterm);
    }

    /**
     * initializeAutumn02
     *
     * A method to initialize due dates for Autumn Quarter 2002
     *
     * @return void
     */
 
    public void initializeAutumn02() {
        // Oct 9 Quiz
        // Oct 24 Proj 1
        // Oct 31 Midterm
        // For each date, instantiate the GregorianCalendar and get the time.
        // We can do this all in one line, or break it up into multiple lines.
        Date quiz = (new GregorianCalendar(2002, 9, 9)).getTime();
        Date projectOne = (new GregorianCalendar(2002, 9, 24)).getTime();
        Date midterm = (new GregorianCalendar(2002, 9, 31)).getTime();
        sendAlert(quiz, projectOne, midterm);
    }

 
    /**
     * sendAlert
     *
     * A method to send alerts based on due dates
     *
     * @param quiz the due date of the quiz
     * @param projectOne the due date of projectOne
     * @param midterm the due date of the midterm
     *
     * @return void
     */
 
    public void sendAlert(Date quiz, Date projectOne, Date midterm) {
        // Get the current date so that we can make comparisons
        // and print informational statements.
        Date now = new Date();
 
        // Have we already had the quiz?
        if (now.after(quiz)) {
            System.out.println("Did you take your quiz?  I hope so!");
        } else {
            System.out.println("Study for the quiz!");
        }
 
        // Have we already had Project One?
        if (now.after(projectOne)) {
            System.out.println("Did you finish Project One?  I hope so!");
        } else {
            System.out.println("How is Project One coming?  Thank goodness you have more time!");
        }
 
        // Have we already had the midterm?
        if (now.after(midterm)) {
            System.out.println("Did you take the midterm?  I hope so!");
        } else {
            System.out.println("Study for the midterm!");
        }
    }
 
    /**
     * main
     *
     * Method called when the program is run.
     */
 
    public static void main(String args[]) {
        DueDates dueDates;
        // An example of using two different constructors.
        // If an argument was provided, pass it up to the appropriate constructor.
        // If not, just use the default constructor.
        if (args.length == 1) {
            dueDates = new DueDates(args[0]);
        } else {
            dueDates = new DueDates();
        }
 
    }

}
 

 The Results
 
 

Created by:  Brandan Jones January 4, 2002