/*
* $Id: EmailValidator.java 280974 2005-09-15 00:06:59Z niallp $
* $Rev: 280974 $
* $Date: 2005-09-15 01:06:59 +0100 (Thu, 15 Sep 2005) $
*
* ====================================================================
* Copyright 2001-2005 The Apache Software Foundation
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package org.apache.commons.validator;
import org.apache.oro.text.perl.Perl5Util;
/**
* <p>
* Perform email validations.
* </p>
* <p>
* This class is a Singleton; you can retrieve the instance via the getInstance() method.
* </p>
* <p>
* Based on a script by <a href="mailto:stamhankar@hotmail.com">Sandeep V. Tamhankar</a> http://javascript.internet.com
* </p>
* <p>
* This implementation is not guaranteed to catch all possible errors in an email address. For example, an address like
* nobody@noplace.somedog will pass validator, even though there is no TLD "somedog"
* </p>
* .
*
* @since Validator 1.1
*/
public class EmailValidator {
private static final String SPECIAL_CHARS = "\\(\\)<>@,;:'\\\\\\\"\\.\\[\\]";
private static final String VALID_CHARS = "[^\\s" + SPECIAL_CHARS + "]";
private static final String QUOTED_USER = "(\"[^\"]*\")";
private static final String ATOM = VALID_CHARS + '+';
private static final String WORD = "((" + VALID_CHARS + "|')+|" + QUOTED_USER + ")";
// Each pattern must be surrounded by /
private static final String LEGAL_ASCII_PATTERN = "/^[\\000-\\177]+$/";
private static final String EMAIL_PATTERN = "/^(.+)@(.+)$/";
private static final String IP_DOMAIN_PATTERN =
"/^\\[(\\d{1,3})[.](\\d{1,3})[.](\\d{1,3})[.](\\d{1,3})\\]$/";
private static final String TLD_PATTERN = "/^([a-zA-Z]+)$/";
private static final String USER_PATTERN = "/^\\s*" + WORD + "(\\." + WORD + ")*\\s*$/";
private static final String DOMAIN_PATTERN = "/^\\s*" + ATOM + "(\\." + ATOM + ")*\\s*$/";
private static final String ATOM_PATTERN = "/(" + ATOM + ")/";
/**
* Singleton instance of this class.
*/
private static final EmailValidator instance = new EmailValidator();
/**
* Returns the Singleton instance of this validator.
*
* @return singleton instance of this validator.
*/
public static EmailValidator getInstance() {
return instance;
}
/**
* Protected constructor for subclasses to use.
*/
protected EmailValidator() {
super();
}
/**
* <p>
* Checks if a field has a valid e-mail address.
* </p>
*
* @param email The value validation is being performed on. A <code>null</code> value is considered invalid.
* @return true if the email address is valid.
*/
public boolean isValid(String email) {
if (email == null) {
return false;
}
Perl5Util matchAsciiPat = new Perl5Util();
if (!matchAsciiPat.match(LEGAL_ASCII_PATTERN, email)) {
return false;
}
email = stripComments(email);
// Check the whole email address structure
Perl5Util emailMatcher = new Perl5Util();
if (!emailMatcher.match(EMAIL_PATTERN, email)) {
return false;
}
if (email.endsWith(".")) {
return false;
}
if (!isValidUser(emailMatcher.group(1))) {
return false;
}
if (!isValidDomain(emailMatcher.group(2))) {
return false;
}
return true;
}
/**
* Returns true if the domain component of an email address is valid.
*
* @param domain being validatied.
* @return true if the email address's domain is valid.
*/
protected boolean isValidDomain(String domain) {
boolean symbolic = false;
Perl5Util ipAddressMatcher = new Perl5Util();
if (ipAddressMatcher.match(IP_DOMAIN_PATTERN, domain)) {
if (!isValidIpAddress(ipAddressMatcher)) {
return false;
} else {
return true;
}
} else {
// Domain is symbolic name
Perl5Util domainMatcher = new Perl5Util();
symbolic = domainMatcher.match(DOMAIN_PATTERN, domain);
}
if (symbolic) {
if (!isValidSymbolicDomain(domain)) {
return false;
}
} else {
return false;
}
return true;
}
/**
* Returns true if the user component of an email address is valid.
*
* @param user being validated
* @return true if the user name is valid.
*/
protected boolean isValidUser(String user) {
Perl5Util userMatcher = new Perl5Util();
return userMatcher.match(USER_PATTERN, user);
}
/**
* Validates an IP address. Returns true if valid.
*
* @param ipAddressMatcher Pattren matcher
* @return true if the ip address is valid.
*/
protected boolean isValidIpAddress(Perl5Util ipAddressMatcher) {
for (int i = 1; i <= 4; i++) {
String ipSegment = ipAddressMatcher.group(i);
if (ipSegment == null || ipSegment.length() <= 0) {
return false;
}
int iIpSegment = 0;
try {
iIpSegment = Integer.parseInt(ipSegment);
} catch (NumberFormatException e) {
return false;
}
if (iIpSegment > 255) {
return false;
}
}
return true;
}
/**
* Validates a symbolic domain name. Returns true if it's valid.
*
* @param domain symbolic domain name
* @return true if the symbolic domain name is valid.
*/
protected boolean isValidSymbolicDomain(String domain) {
String[] domainSegment = new String[10];
boolean match = true;
int i = 0;
Perl5Util atomMatcher = new Perl5Util();
while (match) {
match = atomMatcher.match(ATOM_PATTERN, domain);
if (match) {
domainSegment[i] = atomMatcher.group(1);
int l = domainSegment[i].length() + 1;
domain =
(l >= domain.length())
? ""
: domain.substring(l);
i++;
}
}
int len = i;
// Make sure there's a host name preceding the domain.
if (len < 2) {
return false;
}
// TODO: the tld should be checked against some sort of configurable
// list
String tld = domainSegment[len - 1];
if (tld.length() > 1) {
Perl5Util matchTldPat = new Perl5Util();
if (!matchTldPat.match(TLD_PATTERN, tld)) {
return false;
}
} else {
return false;
}
return true;
}
/**
* Recursively remove comments, and replace with a single space. The simpler
* regexps in the Email Addressing FAQ are imperfect - they will miss escaped
* chars in atoms, for example.
* Derived From Mail::RFC822::Address
*
* @param emailStr The email address
* @return address with comments removed.
*/
protected String stripComments(String emailStr) {
String input = emailStr;
String result = emailStr;
String commentPat = "s/^((?:[^\"\\\\]|\\\\.)*(?:\"(?:[^\"\\\\]|\\\\.)*\"(?:[^\"\\\\]|\111111\\\\.)*)*)\\((?:[^()\\\\]|\\\\.)*\\)/$1 /osx";
Perl5Util commentMatcher = new Perl5Util();
result = commentMatcher.substitute(commentPat, input);
// This really needs to be =~ or Perl5Matcher comparison
while (!result.equals(input)) {
input = result;
result = commentMatcher.substitute(commentPat, input);
}
return result;
}
}