validating day and month using SimpleDateFormat

[Vishnu Munnangi]

Hi Everyone,

I have a question to ask regarding the SimpleDateFormat class.
In my code i am having a date string and i am converting it to a date. and validating if the month entered is greater than max month and if day is greater than max day. If so i want to throw the error.
Here is my piece of code.

String vGrantdate = "15/30/2005";
DateFormat formatter = new SimpleDateFormat("MM/dd/yyyy");
Date parseDate = null;
try{
parseDate = formatter.parse(vGrantdate);
System.out.println(parseDate);
}catch(ParseException ex){
System.out.println(ex.getLocalizedMessage());
}
dtCalendar = Calendar.getInstance();
dtCalendar.setTime(parseDate);
int nDay = dtCalendar.get(Calendar.DAY_OF_MONTH);
int nMaxDay = dtCalendar.getActualMaximum(Calendar.DAY_OF_MONTH);
int nMonth = dtCalendar.get(Calendar.MONTH);
int nMaxMonth = dtCalendar.getActualMaximum(Calendar.MONTH);
if (nMonth > nMaxMonth) {
System.out.println("The month is incorrect");
}else{
System.out.println("month is :" + nMonth + "Max month is:" +nMaxMonth );
}
if (nDay > nMaxDay) {
System.out.println("The day is incorrect");
}else{
System.out.println("day is :" + nDay + "Max day is: " + nMaxDay);
}
here i get the output as
"Thu Mar 30 00:00:00 CST 2006"
month is :2 Max month is: 11
day is :30 Max day is: 31

where in i expect the output to be
The month is incorrect
The day is incorrect
Can any pl explain how to get this.

Thanks in advance.

[Jeff Albertson]

Or you can use DateFormat's setLenient method.

import java.text.*;
import java.util.*;
 
public class Test {
    public static void main(String[] args) throws ParseException {
        DateFormat formatter = new SimpleDateFormat("MM/dd/yyyy");
        formatter.setLenient(false);
        Date date1 = formatter.parse("2/28/2005");
        Date date2 = formatter.parse("2/29/2005");
    }
}

[Vishnu Munnangi]

Thanks for the reply Jeff.

I tried to put formatter.setLenient(false); in my code, but now i get a different error when i execute my code.

 
String vGrantdate = "15/30/2005";
DateFormat formatter = new SimpleDateFormat("MM/dd/yyyy");
formatter.setLenient(false);
Date parseDate = null;
try{
parseDate = formatter.parse(vGrantdate);
System.out.println(parseDate);
}catch(ParseException ex){
System.out.println(ex.getLocalizedMessage());
}
dtCalendar = Calendar.getInstance();
dtCalendar.setTime(parseDate);//1 Here i am getting the error
int nDay = dtCalendar.get(Calendar.DAY_OF_MONTH);
int nMaxDay = dtCalendar.getActualMaximum(Calendar.DAY_OF_MONTH);
int nMonth = dtCalendar.get(Calendar.MONTH);
int nMaxMonth = dtCalendar.getActualMaximum(Calendar.MONTH);
if (nMonth > nMaxMonth) {
System.out.println("The month is incorrect");
}else{
System.out.println("month is :" + nMonth + "Max month is:" +nMaxMonth );
}
if (nDay > nMaxDay) {
System.out.println("The day is incorrect");
}else{
System.out.println("day is :" + nDay + "Max day is: " + nMaxDay);
}

now the output i get is

java.lang.NullPointerException
at java.util.Calendar.setTime(Calendar.java:879)
at package1.DateValidation.main(DateValidation.java:47)
Exception in thread "main" Unparseable date: "15/30/2005"

when i enter a wrong date 15/12/2005, dtCalendar.setTime(parseDate);
dtCalendar is not setting this wrong date i guess.

Can any one pl explain me how to set a wrong date so that i can do the validations for month and day if they are more than the max allowed month/day.

Thanks very much.

[Jeff Albertson]

The code you wrote in your last post is flawed: if the date string is invalid,
parse throws an exception, but you catch it and continue with a null date, so it's not suprising that a NullPointerException is around the corner. The simplest thing to do is report an error like "invalid date". Being able to report "invalid month" versus "invalid day for given month" is going to be more trouble than it's worth, imho.