Date Validation Question

[Stang02GT]

I have been asked to validate a date on our web-page so that people cannot enter dates like 14/1/08 or 2/30/06. I have found code that will do exactly what i need it to do, but i am not sure how to call it. It was suggested to be to have it run through an if statement and if the user enters an invalid date it will kick them to an error page.

Here is the date validation code.

// date validation using SimpleDateFormat
// it will take a string and make sure it's in the proper 
// format as defined by you, and it will also make sure that
// it's a legal date
 
public boolean isValidDate(String date)
{
   // set date format, this can be changed to whatever format
   // you want, MM-dd-yyyy, MM.dd.yyyy, dd.MM.yyyy etc.
   // you can read more about it here:
   // http://java.sun.com/j2se/1.4.2/docs/api/index.html
 
   SimpleDateFormat sdf = new SimpleDateFormat("MM/dd/yyyy");
 
   // declare and initialize testDate variable, this is what will hold
   // our converted string
 
   Date testDate = null;
 
   // we will now try to parse the string into date form
   try
   {
     testDate = sdf.parse(date);
   }
 
   // if the format of the string provided doesn't match the format we 
   // declared in SimpleDateFormat() we will get an exception
 
   catch (ParseException e)
   {
     errorMessage = "the date you provided is in an invalid date" +
                             " format.";
     return false;
   }
 
   // dateformat.parse will accept any date as long as it's in the format
   // you defined, it simply rolls dates over, for example, december 32 
   // becomes jan 1 and december 0 becomes november 30
   // This statement will make sure that once the string 
   // has been checked for proper formatting that the date is still the 
   // date that was entered, if it's not, we assume that the date is invalid
 
   if (!sdf.format(testDate).equals(date)) 
   {
     errorMessage = "The date that you provided is invalid.";
     return false;
   }
 
   // if we make it to here without getting an error it is assumed that
   // the date was a valid one and that it's in the proper format
 
   return true;
 
} // end isValidDate
 

I'm not to sure about the syntax of java or how to do this, lol thats why i'm asking you guys, but


if (!Validator.isValidDate(fromDate)) {
LOG.fine("From Date contains an invalid date:" + fromDate);
return mapping.findForward(NOT_FOUND_FORWARD);
}

What i THINK this will do is run the code from the isValidDate method to check the date in the fromDate field, and if it is not right it will kick them to the NOT_FOUND_FORWARD page and tell them that From Date contains an invalid date.


That is pretty much what I want to is check the fromDate and toDate fields and make sure they are valid and if not kick them to an error page.

Hopefully i didn't confuse anyone lol.

[r035198x]

If you want the method to be available without creating an instance of its enclosing class then make it static as well and Just call it like you've done above.

[Stang02GT]

Ok, well now i guess my next question would be there is also a toDate field, is there a way that i can include bother fromDate and toDate in one statement could i start it like this?

if (!Validator.isValid(fromDate) || !Validator.isValid(toDate))

How can i change the rest of my if statement to include toDate?

I apologize for my lack of knowledge in Java :( I'm just starting to learn it.

[BigDaddyLH]

Ok, well now i guess my next question would be there is also a toDate field, is there a way that i can include bother fromDate and toDate in one statement could i start it like this?

if (!Validator.isValid(fromDate) || !Validator.isValid(toDate))

Could you? Have you tried it? I suggest you write small unit tests for your code so that you can see if it works without having to go through the web layer for each test.

Unit Testing

[Stang02GT]

For this date validation issue. I am still trying to develop this IF statement. I got side tracked with another project and now have time to go back and focus on this.

So if i need to validate this date, i want to check both fields (fromDate, toDate) against the function. If there is nothing wrong with the date then I just do nothing?
Else send them to the error page telling them they entered an invalid date.

I apologize for my ignorance with this but i am trying to learn Java, could you possibly help me to develop this statement and better understand it?

I have the general idea of what i want to do, but i am not sure how to code it.

[Stang02GT]

Actually I figured it out.

I was thinking too hard about something that was so simple.

if (!Validator.isValid(fromDate) || !Validator.isValid(toDate)) {
    LOG.fine("From Date and To Date are not the correct format:" + fromDate + ", " + toDate);
    return mapping.findForward(NOT_FOUND_FORWARD);
}

This if statement is checking to see if the dates are "not valid". It translates to - "If fromDate is not valid or toDate is not valid, so i just needed to add my code for the error message and I was done.