Recognise an arbitrary date string

Question

I need to be able to recognise date strings. It doesn\'t matter if I can not distinguish between month and date (e.g. 12/12/10), I just need to classify the string as being

Answer 1

I did it with a huge regex (self created):

public static final String DATE_REGEX = "\b([0-9]{1,2} ?([\\-/\\\\] ?[0-9]{1,2} ?| (Jan|Feb|Mar|Apr|May|Jun|Jul|Aug|Sep|Oct|Nov|Dec) ?)([\\-/\\\\]? ?('?[0-9]{2}|[0-9]{4}))?)\b";
public static final Pattern DATE_PATTERN = Pattern.compile(DATE_REGEX, Pattern.CASE_INSENSITIVE); // Case insensitive is to match also "mar" and not only "Mar" for March

public static boolean containsDate(String str)
{
    Matcher matcher = pattern.matcher(str);
    return matcher.matches();
}

This matches following dates:

06 Sep 2010
12-5-2005
07 Mar 95
30 DEC '99
11\9\2001

And not this:

444/11/11
bla11/11/11
11/11/11blah

It also matches dates between symbols like [],(), ,:

Yesterday (6 nov 2010)

It matches dates without year:

Yesterday, 6 nov, was a rainy day...

But it matches:

86-44/1234
00-00-0000
11\11/11

And this doesn't look not anymore like a date. But this is something you can solve by checking if the numbers are possible values for a month, day, year.