EmailValidator.java
/*
* Licensed to the Apache Software Foundation (ASF) under one or more
* contributor license agreements. See the NOTICE file distributed with
* this work for additional information regarding copyright ownership.
* The ASF licenses this file to You 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.routines;
import java.io.Serializable;
import java.util.regex.Matcher;
import java.util.regex.Pattern;
/**
* <p>Perform email validations.</p>
* <p>
* Based on a script by <a href="mailto:stamhankar@hotmail.com">Sandeep V. Tamhankar</a>
* https://javascript.internet.com
* </p>
* <p>
* This implementation is not guaranteed to catch all possible errors in an email address.
* </p>.
*
* @since 1.4
*/
public class EmailValidator implements Serializable {
private static final long serialVersionUID = 1705927040799295880L;
private static final String SPECIAL_CHARS = "\\p{Cntrl}\\(\\)<>@,;:'\\\\\\\"\\.\\[\\]";
private static final String VALID_CHARS = "(\\\\.)|[^\\s" + SPECIAL_CHARS + "]";
private static final String QUOTED_USER = "(\"(\\\\\"|[^\"])*\")";
private static final String WORD = "((" + VALID_CHARS + "|')+|" + QUOTED_USER + ")";
private static final String EMAIL_REGEX = "^(.+)@(\\S+)$";
private static final String IP_DOMAIN_REGEX = "^\\[(.*)\\]$";
private static final String USER_REGEX = "^" + WORD + "(\\." + WORD + ")*$";
private static final Pattern EMAIL_PATTERN = Pattern.compile(EMAIL_REGEX);
private static final Pattern IP_DOMAIN_PATTERN = Pattern.compile(IP_DOMAIN_REGEX);
private static final Pattern USER_PATTERN = Pattern.compile(USER_REGEX);
private static final int MAX_USERNAME_LEN = 64;
/**
* Singleton instance of this class, which
* doesn't consider local addresses as valid.
*/
private static final EmailValidator EMAIL_VALIDATOR = new EmailValidator(false, false);
/**
* Singleton instance of this class, which
* doesn't consider local addresses as valid.
*/
private static final EmailValidator EMAIL_VALIDATOR_WITH_TLD = new EmailValidator(false, true);
/**
* Singleton instance of this class, which does
* consider local addresses valid.
*/
private static final EmailValidator EMAIL_VALIDATOR_WITH_LOCAL = new EmailValidator(true, false);
/**
* Singleton instance of this class, which does
* consider local addresses valid.
*/
private static final EmailValidator EMAIL_VALIDATOR_WITH_LOCAL_WITH_TLD = new EmailValidator(true, true);
/**
* Returns the Singleton instance of this validator.
*
* @return singleton instance of this validator.
*/
public static EmailValidator getInstance() {
return EMAIL_VALIDATOR;
}
/**
* Returns the Singleton instance of this validator,
* with local validation as required.
*
* @param allowLocal Should local addresses be considered valid?
* @return singleton instance of this validator
*/
public static EmailValidator getInstance(final boolean allowLocal) {
return getInstance(allowLocal, false);
}
/**
* Returns the Singleton instance of this validator,
* with local validation as required.
*
* @param allowLocal Should local addresses be considered valid?
* @param allowTld Should TLDs be allowed?
* @return singleton instance of this validator
*/
public static EmailValidator getInstance(final boolean allowLocal, final boolean allowTld) {
if (allowLocal) {
if (allowTld) {
return EMAIL_VALIDATOR_WITH_LOCAL_WITH_TLD;
}
return EMAIL_VALIDATOR_WITH_LOCAL;
}
if (allowTld) {
return EMAIL_VALIDATOR_WITH_TLD;
}
return EMAIL_VALIDATOR;
}
private final boolean allowTld;
private final DomainValidator domainValidator;
/**
* Protected constructor for subclasses to use.
*
* @param allowLocal Should local addresses be considered valid?
*/
protected EmailValidator(final boolean allowLocal) {
this(allowLocal, false);
}
/**
* Protected constructor for subclasses to use.
*
* @param allowLocal Should local addresses be considered valid?
* @param allowTld Should TLDs be allowed?
*/
protected EmailValidator(final boolean allowLocal, final boolean allowTld) {
this.allowTld = allowTld;
this.domainValidator = DomainValidator.getInstance(allowLocal);
}
/**
* constructor for creating instances with the specified domainValidator
*
* @param allowLocal Should local addresses be considered valid?
* @param allowTld Should TLDs be allowed?
* @param domainValidator allow override of the DomainValidator.
* The instance must have the same allowLocal setting.
* @since 1.7
*/
public EmailValidator(final boolean allowLocal, final boolean allowTld, final DomainValidator domainValidator) {
this.allowTld = allowTld;
if (domainValidator == null) {
throw new IllegalArgumentException("DomainValidator cannot be null");
}
if (domainValidator.isAllowLocal() != allowLocal) {
throw new IllegalArgumentException("DomainValidator must agree with allowLocal setting");
}
this.domainValidator = domainValidator;
}
/**
* <p>Checks if a field has a valid e-mail address.</p>
*
* @param email The value validation is being performed on. A {@code null}
* value is considered invalid.
* @return true if the email address is valid.
*/
public boolean isValid(final String email) {
if (email == null) {
return false;
}
if (email.endsWith(".")) { // check this first - it's cheap!
return false;
}
// Check the whole email address structure
final Matcher emailMatcher = EMAIL_PATTERN.matcher(email);
if (!emailMatcher.matches()) {
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 validated, may be in IDN format
* @return true if the email address's domain is valid.
*/
protected boolean isValidDomain(final String domain) {
// see if domain is an IP address in brackets
final Matcher ipDomainMatcher = IP_DOMAIN_PATTERN.matcher(domain);
if (ipDomainMatcher.matches()) {
final InetAddressValidator inetAddressValidator =
InetAddressValidator.getInstance();
return inetAddressValidator.isValid(ipDomainMatcher.group(1));
}
// Domain is symbolic name
if (allowTld) {
return domainValidator.isValid(domain) || !domain.startsWith(".") && domainValidator.isValidTld(domain);
}
return domainValidator.isValid(domain);
}
/**
* 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(final String user) {
if (user == null || user.length() > MAX_USERNAME_LEN) {
return false;
}
return USER_PATTERN.matcher(user).matches();
}
}