// An alias (or commonly called "nickname") is: // Nickname must begin with a letter. // Only letters a-z, numbers 0-9, or . are allowed in Nickname field. public static boolean isAlias(String string) { if (!MmsConfig.isAliasEnabled()) { return false; } int len = string == null ? 0 : string.length(); if (len < MmsConfig.getAliasMinChars() || len > MmsConfig.getAliasMaxChars()) { return false; } if (!Character.isLetter(string.charAt(0))) { // Nickname begins with a letter return false; } for (int i = 1; i < len; i++) { char c = string.charAt(i); if (!(Character.isLetterOrDigit(c) || c == '.')) { return false; } } return true; }