Validation Utillity Methods

Utility methods which include validations for Zipcode ,SSN ,creditcard as per US conventions email,and Alpha-Numeric check

import java.text.NumberFormat;
import java.text.SimpleDateFormat;
import java.util.Calendar;
import java.util.Hashtable;
import java.util.Locale;
import java.util.Properties;
import java.util.StringTokenizer;

import org.apache.log4j.Logger;


public class Util {

 /**
  * Checks the given zip code to see if it adhears
  * the 5-4 format (with no hyphen)
  *
  * @param zip code to check
  * @return true if proper format, false otherwise.
  */
 public static boolean isZipValidNoHyphen(String zip)
 {
  final String valid = "0123456789";

  //check for null
  if (zip==null) {
   return false;
  }

  // first check length: must be 5 or 9
  if (zip.length() != 5 && zip.length() != 9)
  {
   return false;
  }

  // iterate thru string checking each char is valid
  for (int i=0; i < zip.length(); i++)
  {
   String temp = zip.substring(i, i+1);

   // make sure the current char is part of valid chars
   if (valid.indexOf(temp) == -1)
   {
    return false;
   }
  }
  return true;
 }


 /**
  * Checks the given zip code to see if it adhears
  * the 5-4 format (with hyphen).
  *
  * @param zip code to check
  * @return true if proper format, false otherwise.
  */
 public static boolean isZipValid(String zip)
 {
  final String valid = "0123456789-";
  int hyphencount = 0;

  //check for null
  if (zip==null) {
   return false;
  }

  // first check length: must be 5 or 10
  if (zip.length() != 5 && zip.length() != 10)
  {
   return false;
  }

  // if the length is 10, make sure a hypen occures
  // at the proper location
  if ( (zip.length() == 10) &&
      (zip.charAt(5) != '-') )
  {
   return false;
  }

  // iterate thru string checking each char is valid
  for (int i=0; i < zip.length(); i++)
  {
   String temp = zip.substring(i, i+1);
   if (temp.equals("-"))
    hyphencount++;

   // make sure the current char is part of valid chars
   if (valid.indexOf(temp) == -1)
   {
    return false;
   }

   // make sure there is only one hypen possible
   if (hyphencount > 1)
   {
    return false;
      }
  }
  return true;
 }

 /**
  * Checks the given zip code to see if it
  * is 5 numeric digits.
  *
  * @param zip code to check
  * @return true if proper format, false otherwise.
  */
 public static boolean isZipFiveDigits(String zip)
 {
  final String valid = "0123456789";

  //check for null
  if (zip==null) {
   return false;
  }

  // first check length: must be 5
  if (zip.length() != 5)
  {
   return false;
  }

  // iterate thru string checking each char is valid
  for (int i=0; i < zip.length(); i++)
  {
   String temp = zip.substring(i, i+1);

   // make sure the current char is part of valid chars
   if (valid.indexOf(temp) == -1)
   {
    return false;
   }
  }
  return true;
 }

 /**
  * Checks to see if zipPlusFour is 4 numeric digits
  *
  * @param zipPlusFour to check
  * @return true if proper format, false otherwise.
  */
 public static boolean isZipPlusFourValid(String zipPlusFour)
 {
  final String valid = "0123456789";

  //check for null
  if (zipPlusFour==null) {
   return false;
  }

  // first check length: must be 4
  if (zipPlusFour.length() != 4)
  {
   return false;
  }

  // iterate thru string checking each char is valid
  for (int i=0; i < zipPlusFour.length(); i++)
  {
   String temp = zipPlusFour.substring(i, i+1);

   // make sure the current char is part of valid chars
   if (valid.indexOf(temp) == -1)
   {
    return false;
   }
  }
  return true;
 }


 /**
  * Checks to see if SSN is 9 numeric digits
  *
  * @param ssn to check
  * @return true if proper format, false otherwise.
  */
 public static boolean isSSNValid(String ssn)
 {
  final String valid = "0123456789";

  //check for null
  if (ssn==null) {
   return false;
  }

  // first check length: must be 9
  if (ssn.length() != 9)
  {
   return false;
  }

  // iterate thru string checking each char is valid
  for (int i=0; i < ssn.length(); i++)
  {
   String temp = ssn.substring(i, i+1);

   // make sure the current char is part of valid chars
   if (valid.indexOf(temp) == -1)
   {
    return false;
   }
  }
  return true;
 }


 /** checks for a valid email
  *
  * @param an email address
  * @return false for invalid addresses, true otherwise
  *
  */
 public static boolean isValidEmail(String email)
 {
  //check for null
  if (email==null) {
   return false;
  }

    // check the length
    if (email.length() < 5)
    {
       // a@b.c should be the shortest an
       // address could be
       return false;
    }

    // check format
    // email must have at least one "@"
    if (email.indexOf('@') == -1)
    {
       return false;
    }

    // email must have at least one "."
    if (email.indexOf('.') == -1)
    {
   return false;
    }

   // make sure email has at least 1
       if ( //((email.length() - (email.lastIndexOf('.') + 1)) > 3) ||
      ((email.length() - (email.lastIndexOf('.') + 1)) < 1) )
    {
      return false;
    }

    // make sure there is no "_" after the "@"
    if ( (email.indexOf('_') != -1) &&
         (email.lastIndexOf('_') > email.lastIndexOf('@')) )
  {
    return false;
  }

  // make sure there is only one "@"
  // and each character is valid [a-z, 0-9, @, ., -, _]
  int atCnt = 0;

  for (int i=0; i < email.length(); i++)
  {
   char temp = email.charAt(i);
   if (temp == '@')
    atCnt++;

   // make sure there is only one @ possible
   if (atCnt > 1)
   {
    return false;
      }

   // make sure the current char is part of valid chars
   if ( (!isDigit(temp)) &&
     (!isAlpha(temp)) &&
     (temp != '@') &&
     (temp != '.') &&
     (temp != '-') &&
     (temp != '_') )
   {
    return false;
   }
  }

  // at this point we passed all checks
  return true;
 }



 /**
  * Method isCreditCardValid
  * Checks if the given credit card number is valid.
  *
  * @param cc
  * @return boolean
  */
 public static boolean isCreditCardValid(String cc)
 {
  final String valid = "0123456789";
  int sum = 0;
     int digit = 0;
     int addend = 0;
     boolean timesTwo = false;

  //check for null
  if (cc==null) {
   return false;
  }

  // first check length: must be 13-16 digits
  if (cc.length() < 13 || cc.length() > 16)
  {
   return false;
  }

  // iterate thru string checking each char is valid (numeric)
  for (int i=0; i < cc.length(); i++)
  {
   String temp = cc.substring(i, i+1);

   // make sure the current char is part of valid chars
   if (valid.indexOf(temp) == -1)
   {
    return false;
   }
  }

  // perform Luhn check for credit card number validity
  for (int i = cc.length () - 1; i >= 0; i--)
  {
         digit = Integer.parseInt (cc.substring (i, i + 1));
         if (timesTwo)
         {
             addend = digit * 2;
            if (addend > 9)
            {
             addend -= 9;
          }
        }
        else
        {
          addend = digit;
        }
        sum += addend;
        timesTwo = !timesTwo;
     }

     int modulus = sum % 10;

     if (modulus != 0)
     {
      return false;
     }

  return true;
 }




 /**
  * Checks if a given string is valid for credit info
  *
  * @param string to check
  * @return true if valid, false otherwise
  */
 public static boolean isValidForCreditInfo(String aName)
 {
  String temp;
  char tempChar;

  //check for null
  if (aName==null) {
   return false;
  }

  // iterate thru string checking each char is valid
  for (int i=0; i < aName.length(); i++)
  {
   temp = aName.substring(i, i+1);
   tempChar = temp.charAt(0);

   // make sure the current char is part of valid chars for credit info
   if ( (!isDigit(tempChar)) &&
     (!isAlpha(tempChar)) &&
     (tempChar != ' ') &&
     (tempChar != '&') &&
     (tempChar != '-') &&
     (tempChar != '\'') )
   {
    return false;
   }
  }
  return true;
 }


 /**
   * Checks the given string to see if it is numeric
   *
   * @param string to check
   * @return true if proper format, false otherwise.
   */
  public static boolean isNumeric(String aString)
  {
   final String valid = "0123456789";

   //check for null
   if (aString==null) {
    return false;
   }

   // iterate thru string checking each char is valid
   for (int i=0; i < aString.length(); i++)
   {
    String temp = aString.substring(i, i+1);

    // make sure the current char is part of valid chars
    if (valid.indexOf(temp) == -1)
    {
     return false;
    }
   }
   return true;
  }


 /**
  * Checks if the given character is a digit.
  *
  * @param char to check
  * @return true if char is 0 - 9, false otherwise.
  */
 public static boolean isDigit(char ch)
 {
  if ( (Character.toLowerCase(ch) >= '0') &&
   (Character.toLowerCase(ch) <= '9') )
  {
   return true;
  }
  else
  {
   return false;
  }
 }

 /**
  * Checks if the given character is an alpha.
  *
  * @param char to check
  * @return true if char is A-Z or a-z, false otherwise.
  */
 public static boolean isAlpha(char ch)
 {
  if ( (Character.toLowerCase(ch) >= 'a') &&
   (Character.toLowerCase(ch) <= 'z') )
  {
   return true;
  }
  else
  {
   return false;
  }
 }



}