Date Validation !!!

[Maria Laxmi]

Hi,

I am using parse function for date validation to parse the valid format of the date "mm-dd-yyyy". Now if I give the input date is "04-31-2008", which is a valid format but invalid date for the April month as we don't have 31st in April, parse function throws an exception but I want to catch this exception before It parses the date.In short I want to separate this two validation for Invalid Format and Invalid date. And I am unable to figure out how can I do this?

Thanks,

[Rob Spoor]

Use a DateFormat with setLenient(false) called on it.

[Campbell Ritchie]

How about a regular expression to validate the format?

[Maria Laxmi]

I tried setLenient(false), but it is not working.

Thanks,

[Campbell Ritchie]

Throwing an Exception from 04-31-2009 for 31st April 2009 would appear to be "working correctly."

[Maria Laxmi]

I know its working with parse function, but I want to catch this before date gets parsed.

e.g. my code is
DateFormat dateformat = new SimpleDateFormat(mm-dd-yyyy)
dateFormat.setLenient(false)
dateFormat.parse(dateStr)

parse function validates this exception of not allowing 04-31-2009, but I want to catch it before calling the parse function. I am not sure it is possible or not

Thanks,

[Paul Clapham]

nis bootwala wrote:I know its working with parse function, but I want to catch this before date gets parsed.

Why? The purpose of the parse() method is to convert a String to a Date, and to throw an exception if that can't be done.

[Rob Spoor]

You can use another form of parse that will not throw an exception:

ParsePosition position = new ParsePosition(0);
dateFormat.parse(dateStr, position);
// position.getErrorIndex() will return a value > -1 if there was an error
// position.getIndex() will return the position after the valid date

I have used this myself to make sure that there is no "clutter" after the valid string, e.g. "04-30-2009abc":

ParsePosition pos = new ParsePosition(0);
Date result = format.parse(source, pos);
int index = pos.getIndex();
if (index == 0 || index != source.length()) // see below
{
    int error = pos.getErrorIndex();
    if (error != -1)
    {
        // no error detected by the format, so there is trailing clutter
        error = index;
    }
    throw new ParseException("Unparseable date: \"" + source + "\"", index);
}
return result;

pos.getIndex() is guaranteed to not change if there is an error, so in this case it will remain 0.