Validasi Email di Blackberry

Berikut adalah method untuk mengecek apakah email tersebut valid atau tidak, jika nilainya true maka valid dan sebaliknya.

public boolean isValidEmailAddress(String email) {
   if (email == null || email.length() == 0 || email.indexOf("@") == -1 || email.indexOf(" ") != -1) {
      return false;
   }
   int emailLenght = email.length();
   int atPosition = email.indexOf("@");

   String beforeAt = email.substring(0, atPosition);
   String afterAt = email.substring(atPosition + 1, emailLenght);

   if (beforeAt.length() == 0 || afterAt.length() == 0) {
      return false;
   }
   if (email.charAt(atPosition - 1) == '.') {
      return false;
   }
   if (email.charAt(atPosition + 1) == '.') {
      return false;
   }
   if (afterAt.indexOf(".") == -1) {
      return false;
   }
   char dotCh = 0;
   for (int i = 0; i < afterAt.length(); i++) {
      char ch = afterAt.charAt(i);
      if ((ch == 0x2e) && (ch == dotCh)) {
         return false;
      }
      dotCh = ch;
   }
   if (afterAt.indexOf("@") != -1) {
      return false;
   }

   for (int i = 0; i < afterAt.length(); i++) {
      char ch = afterAt.charAt(i);
      if (!((ch >= 0x30 && ch <= 0x39) || (ch >= 0x41 && ch <= 0x5a) || (ch >= 0x61 && ch <= 0x7a) || (ch == 0x2e) || (ch == 0x2d) || (ch == 0x5f))) {
         return false;
      }
      if ((ch == 0x2e) && (ch == dotCh)) {
         return false;
      }
      dotCh = ch;
   }

   dotCh = 0;
   for (int i = 0; i < beforeAt.length(); i++) {
      char ch = beforeAt.charAt(i);
      if (!((ch >= 0x30 && ch <= 0x39) || (ch >= 0x41 && ch <= 0x5a) || (ch >= 0x61 && ch <= 0x7a) || (ch == 0x2e) || (ch == 0x2d) || (ch == 0x5f))) {
         return false;
      }
      if ((ch == 0x2e) && (ch == dotCh)) {
         return false;
      }
      dotCh = ch;
   }
  
   if(email.startsWith(".")){
      return false;
   }
  
   int lastIndex = email.lastIndexOf('.');
   String lastToken = email.substring(lastIndex + 1);
   if (lastToken.length() >= 2) {
      if (lastToken.length() <= 3){
          //return true;
      }else{
          return false;
      }
   }else{
      return false;
   }
        
   return true;
}