confusing output of a date

[jhon max]

  public class ExpirationDate {

    // the object for the instance of the date
    private GregorianCalendar gCal;

    // format for the full display of the given expiration date
    private SimpleDateFormat fullExpirationDate;

    // numerical format for the given expiration year
    private SimpleDateFormat yearInteger;

    // numerical format for the given expiration month
    private SimpleDateFormat monthInteger;

    // short string format of the given expiration month
    private SimpleDateFormat monthShortString;

    // full string format of the given expiration month
    private SimpleDateFormat monthFullString;

    // numerical format of the given expiration day in year
    private SimpleDateFormat dayInYearInteger;

    // numerical format of the given expiration day in month
    private SimpleDateFormat dayInMonthInteger;

    // short string format of the given expiration day in week
    private SimpleDateFormat dayInWeekShortString;

    // full string format of the given expiration day in week
    private SimpleDateFormat dayInWeekFullString;
    
    protected ExpirationDate() {

        yearInteger = new SimpleDateFormat("yy");
        monthInteger = new SimpleDateFormat("MM");
        monthShortString = new SimpleDateFormat("MMM");
        monthFullString = new SimpleDateFormat("MMMMM");
        dayInYearInteger = new SimpleDateFormat("DDD");
        dayInMonthInteger = new SimpleDateFormat("dd");
        dayInWeekShortString = new SimpleDateFormat("E");
        dayInWeekFullString = new SimpleDateFormat("EEEE");
    }

    /**
     * Returns a full value of the given expiration date.
     * 
     * @return a full value of this expiration date
     */
    public ExpirationDate getFullExpirationDate() {

        ExpirationDate eD = new ExpirationDate();

        eD.setExpirationDate(Integer.parseInt(this.getExpirationYearInNumber()),
                             Integer.parseInt(this.getExpirationMonthInNumber()),
                             Integer.parseInt(this.getExpirationDayInMonthInDigits()));

        return eD;
    }

    /**
     * @return the full string format of the given expiration date
     */
    public String toString() {

        return this.getExpirationMonthFullString() + ", " + this.getExpirationDayInMonthInDigits() + ", " +
               this.getExpirationYearInNumber() + " - " + this.getExpirationDayInWeekFullString();
    }

    /**
     * Sets the expiration date.
     * 
     * @param year      expiration year
     * @param month     expiration month
     * @param day       expiration day
     */
    public void setExpirationDate(int year, int month, int day) {
        
        gCal = new GregorianCalendar(year, month - 1, day);
    }

    /**
     * Returns the year format of the given year, the return value of this
     * SimpleDateFormat object is only the last two digits of the given year,
     * so there is an additional first 2 digits to represent a full string
     * representation of a given year.
     * 
     * @return the given expiration year 
     */
    public String getExpirationYearInNumber() {

        return "20" + yearInteger.format(gCal.getTime());
    }
    
    /**
     * Returns the numerical representaion of the given expiration month.
     * 
     * @return the given expiration month in two digits
     */
    public String getExpirationMonthInNumber() {

        return monthInteger.format(gCal.getTime());
    }

    /**
     * Returns a short string representaion of the given expiration month.
     *
     * Example: October -->> oct
     * 
     * @return a short strin representaion of the given expiration month
     */
    public String getExpirationMonthShortString() {

        return monthShortString.format(gCal.getTime());
    }

    /**
     * Returns the full string representation of the given expiration month.
     * 
     * @return the full representaion of the given expiration month
     */
    public String getExpirationMonthFullString() {

        return monthFullString.format(gCal.getTime());
    }

    /**
     * Returns the expiration day in year in numerical format.
     * 
     * @return the numerical representation of the expiration day in year in
     *         3 digits
     */
    public String getExpirationDayInYearInNumber() {

        return dayInYearInteger.format(gCal.getTime());
    }

    /**
     * Returns the expiration day in month in numerical format.
     * 
     * @return the numerical representaion of the expiration day in month
     */
    public String getExpirationDayInMonthInDigits() {

        return dayInMonthInteger.format(gCal.getTime());
    }

    /**
     * Returns the expiration day in week in a short string representation
     *
     * Example: Saturday -->> sat
     * 
     * @return a short string representaion of the expiration day in week
     */
    public String getExpirationDayInWeekShortString() {

        return dayInWeekShortString.format(gCal.getTime());
    }

    /**
     * Returns the full string representation of the expiration day in week.
     * 
     * @return the full string representation of the expiration day in week
     */
    public String getExpirationDayInWeekFullString() {

        return dayInWeekFullString.format(gCal.getTime());
    }

    public static void main(String[] args) {

        ExpirationDate eD = new ExpirationDate();

        eD.setExpirationDate(10, 1, 25);

        System.out.println(eD.getFullExpirationDate());
        System.out.println(eD.getExpirationDayInWeekFullString()); //this one should also display sunday..
    }
}  

output

  
 January, 25, 2010 - Monday
Saturday
 

why is it the program displays saturday???

please help me here....

[Christophe Verré]

eD.setExpirationDate(10, 1, 25);

It should be 2010, not 10. You should figure that out yourself by either debugging through your code, or adding some System.out.println around.

[jhon max]

thank you sir.. i thought the Calendar class will only generate the last two digits of the current year.... thank you sir again!

[jhon max]

the only thing that confuse me is that when i pass the number 10... and when i call the method getFullExpirationDate().. the compiler generates the year exactly
2010...

[Christophe Verré]

jhon max wrote:the only thing that confuse me is that when i pass the number 10... and when i call the method getFullExpirationDate().. the compiler generates the year exactly
2010...

Check what you are doing in getExpirationYearInNumber.

[jhon max]

oh sorry sir for not clearing the problem... what i mean is.. even if i pass a number 10.. the compiler generates the exact year.... im not reffering to the method
getExpirationYearInNUmber()...

The compiler is still reffering to this year....

          ExpirationDate eD = new ExpirationDate();

        eD.setExpirationDate(10, 01, 24);
        System.out.println(eD.getExpirationDayInWeekFullString());
        System.out.println(eD.getFullExpirationDate());
        
        System.out.println("---------------");

        eD.setExpirationDate(2010, 01, 24);
        System.out.println(eD.getExpirationDayInWeekFullString());
        System.out.println(eD.getFullExpirationDate());  

output

  Friday
January, 24, 2010 - Sunday
---------------
Sunday
January, 24, 2010 - Sunday
  

[Christophe Verré]

im not reffering to the method getExpirationYearInNUmber()...

You are calling getExpirationYearInNUmber from getFullExpirationDate, so don't tell me you're not referring to it

[jhon max]

sorry i cant express my thoughts too much.... i cant speak enough english very well ...
so i look my files and found this one...

      private static BufferedReader br = new BufferedReader(new InputStreamReader(System.in));

    public static void main(String[] args) throws IOException {
        
        int year,
            month,
            day;

        GregorianCalendar cal;
        SimpleDateFormat sdf;

        System.out.print("Enter Year: ");
        year = Integer.parseInt(br.readLine());

        System.out.print("Enter Month:");
        month = Integer.parseInt(br.readLine());

        System.out.print("Enter Day: ");
        day = Integer.parseInt(br.readLine());

        cal = new GregorianCalendar(year, month-1, day);
        sdf = new SimpleDateFormat("EE");

        System.out.println("Day Of Week: " + sdf.format(cal.getTime( )));
    }  

if i enter 10 - year
01 - month
24 - day
the outut is

  Enter Year: 10
Enter Month:01
Enter Day: 24
Day Of Week: Fri  // firday
  

but if i enter

   
Enter Year: 2010
Enter Month:01
Enter Day: 24
Day Of Week: Sun // sunday
 

this is what make me confuse...

[Christophe Verré]

eD.setExpirationDate(10, 01, 24);  
System.out.println(eD.getExpirationDayInWeekFullString());  
System.out.println(eD.getFullExpirationDate());  

Here, you call getFullExpirationDate(). In getFullExpirationDate(), you call getExpirationYearInNumber(). getExpirationYearInNumber() return a year, which always starts with "20". So even if start with setExpirationDate(10, 01, 24), when you call getFullExpirationDate(), the returned object's year will be 2010, not 10. You should ask yourself why you are using "20" in getExpirationYearInNumber().

package divers;

import java.text.SimpleDateFormat;
import java.util.GregorianCalendar;

public class ExpirationDate {

    // the object for the instance of the date
    private GregorianCalendar gCal;

    // format for the full display of the given expiration date
    private SimpleDateFormat fullExpirationDate;

    // numerical format for the given expiration year
    private SimpleDateFormat yearInteger;

    // numerical format for the given expiration month
    private SimpleDateFormat monthInteger;

    // short string format of the given expiration month
    private SimpleDateFormat monthShortString;

    // full string format of the given expiration month
    private SimpleDateFormat monthFullString;

    // numerical format of the given expiration day in year
    private SimpleDateFormat dayInYearInteger;

    // numerical format of the given expiration day in month
    private SimpleDateFormat dayInMonthInteger;

    // short string format of the given expiration day in week
    private SimpleDateFormat dayInWeekShortString;

    // full string format of the given expiration day in week
    private SimpleDateFormat dayInWeekFullString;
    
    protected ExpirationDate() {

        yearInteger = new SimpleDateFormat("yy");
        monthInteger = new SimpleDateFormat("MM");
        monthShortString = new SimpleDateFormat("MMM");
        monthFullString = new SimpleDateFormat("MMMMM");
        dayInYearInteger = new SimpleDateFormat("DDD");
        dayInMonthInteger = new SimpleDateFormat("dd");
        dayInWeekShortString = new SimpleDateFormat("E");
        dayInWeekFullString = new SimpleDateFormat("EEEE");
    }

    /**
     * Returns a full value of the given expiration date.
     * 
     * @return a full value of this expiration date
     */
    public ExpirationDate getFullExpirationDate() {
    	System.out.println("getFullExpirationDate() called");
        ExpirationDate eD = new ExpirationDate();

        eD.setExpirationDate(Integer.parseInt(this.getExpirationYearInNumber()),
                             Integer.parseInt(this.getExpirationMonthInNumber()),
                             Integer.parseInt(this.getExpirationDayInMonthInDigits()));

        return eD;
    }

    /**
     * @return the full string format of the given expiration date
     */
    @Override
    public String toString() {

        return this.getExpirationMonthFullString() + ", " + this.getExpirationDayInMonthInDigits() + ", " +
               this.getExpirationYearInNumber() + " - " + this.getExpirationDayInWeekFullString();
    }

    /**
     * Sets the expiration date.
     * 
     * @param year      expiration year
     * @param month     expiration month
     * @param day       expiration day
     */
    public void setExpirationDate(int year, int month, int day) {
        System.out.println("Setting expiration date to " + year + "/" + month + "/" + day);
        gCal = new GregorianCalendar(year, month - 1, day);
    }

    /**
     * Returns the year format of the given year, the return value of this
     * SimpleDateFormat object is only the last two digits of the given year,
     * so there is an additional first 2 digits to represent a full string
     * representation of a given year.
     * 
     * @return the given expiration year 
     */
    public String getExpirationYearInNumber() {
    	System.out.println("Always making the year a 20xx year...");
        return "20" + yearInteger.format(gCal.getTime());
    }
    
    /**
     * Returns the numerical representaion of the given expiration month.
     * 
     * @return the given expiration month in two digits
     */
    public String getExpirationMonthInNumber() {

        return monthInteger.format(gCal.getTime());
    }

    /**
     * Returns a short string representaion of the given expiration month.
     *
     * Example: October -->> oct
     * 
     * @return a short strin representaion of the given expiration month
     */
    public String getExpirationMonthShortString() {

        return monthShortString.format(gCal.getTime());
    }

    /**
     * Returns the full string representation of the given expiration month.
     * 
     * @return the full representaion of the given expiration month
     */
    public String getExpirationMonthFullString() {

        return monthFullString.format(gCal.getTime());
    }

    /**
     * Returns the expiration day in year in numerical format.
     * 
     * @return the numerical representation of the expiration day in year in
     *         3 digits
     */
    public String getExpirationDayInYearInNumber() {

        return dayInYearInteger.format(gCal.getTime());
    }

    /**
     * Returns the expiration day in month in numerical format.
     * 
     * @return the numerical representaion of the expiration day in month
     */
    public String getExpirationDayInMonthInDigits() {

        return dayInMonthInteger.format(gCal.getTime());
    }

    /**
     * Returns the expiration day in week in a short string representation
     *
     * Example: Saturday -->> sat
     * 
     * @return a short string representaion of the expiration day in week
     */
    public String getExpirationDayInWeekShortString() {

        return dayInWeekShortString.format(gCal.getTime());
    }

    /**
     * Returns the full string representation of the expiration day in week.
     * 
     * @return the full string representation of the expiration day in week
     */
    public String getExpirationDayInWeekFullString() {

        return dayInWeekFullString.format(gCal.getTime());
    }

    public static void main(String[] args) {

        ExpirationDate eD = new ExpirationDate();

        eD.setExpirationDate(10, 1, 24);
        System.out.println("==== Step One ====");
        System.out.println(eD.getFullExpirationDate()); // here, the returned date will be 2010, because getExpirationYearInNumber is called
        System.out.println("==== Step Two ====");
        System.out.println(eD.getExpirationDayInWeekFullString()); // here the return date will be 10
    }
}    

[Adeel Ansari]

Precisely, when you enter "10", its interpreted as "0010". Are you getting the point now?

[jhon max]

"10", its interpreted as "0010"

ahh so thats why im getting a wrong date... thats how the compiler generates the specified year.....
tnx!

[Adeel Ansari]

Yes, precisely again . You can try that out yourself by giving 0010 as your input.
Cheers.