Comprehensive Example

• Let's break the DueDates class into multiple classes.  Let's use packages as well.
• What changes do you see from  DueDates ?
• Note:  Four separate public classes follow, which should be in four separate files.  I put them on one slide for discussion purposes.  If you implement this, be sure to put the source in the correct files and packages.

/*
 * Reminder.java
 *
 * Created on February 5, 2002, 3:00 AM
 */

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

// import quarters

import quarters.*;

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

    private Quarter quarter;
 
    /**
     * The default constructor.  Assumes the current quarter is Winter 02.
     */
    public Reminder() {
        // 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");
            quarter = new WinterQuarter();
        } else if (month >= 8 && month <= 11) {
            // initialize autumn quarter dates.
            System.out.println("Initializing Autumn 2002");
            quarter = new AutumnQuarter();
        } 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.");
            System.exit(0);
        }
        sendAlert();
 
    }
 
    /**
     * This constructor assigns the quarter from the command line arguments.
     *
     */
 
    public Reminder(String qtr) {
 
        // initialize to the appropriate quarter based on the command line arguments.
        if (qtr.equals("Winter02")) {
            quarter = new WinterQuarter();
        } else if (qtr.equals("Autumn02")) {
            quarter = new AutumnQuarter();
        } else {
            System.out.println("Invalid command line arguments.  Please try again.");
            System.exit(0);
        }
        sendAlert();
    }

    /**
     * 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() {
        // 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(quarter.getQuiz())) {
            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(quarter.getProjectOne())) {
            System.out.println("Did you finish Project One?  I hope so!");
        } else {
            System.out.println("How is Project One coming?  Thank hevans you have more time!");
        }
 
        // Have we already had the midterm?
        if (now.after(quarter.getMidterm())) {
            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[]) {
        Reminder reminder;
        // 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) {
            reminder = new Reminder(args[0]);
        } else {
            reminder = new Reminder();
        }
 
    }

}
 
 
 

/*
 * Quarter.java
 *
 * Created on February 6, 2002, 12:22 AM
 */

package quarters;

import java.util.*;

/**
 *
 * @author  jonesbr@email.uc.edu
 */

public abstract class Quarter {
 
protected Date quiz = new Date();
protected Date projectOne = new Date();
protected Date midterm = new Date();

    /**
     * method getQuiz
     *
     * An accessor method to return the date of a quiz.
     *
     * @returns Date quiz
     */

    public Date getQuiz() {
        return quiz;
    }

    /**
     * method getProjectOne
     *
     * An accessor method to return the date of a quiz.
     *
     * @returns Date projectOne
     */
 
    public Date getProjectOne() {
         return projectOne;
    }
 
 
    /**
     * method getMidterm
     *
     * An accessor method to return the date of a quiz.
     *
     * @returns Date midterm
     */
 
    public Date getMidterm() {
        return midterm;
    }
}
 
 
 

/*
 * AutumnQuarter.java
 *
 * Created on February 6, 2002, 12:22 AM
 */

package quarters;

/**
 *
 * @author  joensbr@email.uc.edu
 * @version 1.0
 */
public class AutumnQuarter extends Quarter {

    /** Creates a new instance of SpringQuarter */
    public AutumnQuarter() {
        quiz = (new GregorianCalendar(2002, 9, 9)).getTime();
        projectOne = (new GregorianCalendar(2002, 9, 24)).getTime();
        midterm = (new GregorianCalendar(2002, 9, 31)).getTime();
    }

}
 

/*
 * FallQuarter.java
 *
 * Created on February 6, 2002, 12:23 AM
 */

package quarters;

/**
 *
 * @author  jonesbr@email.uc.edu
 * @version 1.0
 */
public class WinterQuarter extends Quarter {

    /** Creates a new instance of FallQuarter */
    public WinterQuarter() {
        quiz = (new GregorianCalendar(2002, 0, 30)).getTime();
        projectOne = (new GregorianCalendar(2002, 1, 13)).getTime();
        midterm = (new GregorianCalendar(2002, 1, 20)).getTime();
    }

}

The Results (without command line arguments):

Initializing Winter 2002
Study for the quiz!
How is Project One coming?  Thank hevans you have more time!
Study for the midterm!
 

 Class Design Hints Discussion

Created by:  Brandan Jones January 4, 2002