contract class validation method

public boolean validate()
{

    boolean             isValid = true;

 /*  if (!fromDate)

    {

        isValid = checkFailed("From Date should be entered");

    }

    if (!toDate)

    {

        isValid = checkFailed("To Date should be entered");

    }

    if (isValid && (fromDate > toDate))

    {

        isValid = checkFailed(strfmt("From Date should be less than or equal to To Date", date2StrUsr(fromDate, DateFlags::FormatAll), date2StrUsr(toDate, DateFlags::FormatAll)));

    }


     if (!Name)

    {

        isValid = checkFailed("Name should be entered");

    }
 */

    return isValid;

}

for validation u have to write this code in contract class class delaration method
contractclassname implements SysOperationValidatable