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/*
* Copyright 2008 Les Hazlewood 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.codemonkey.simplejavamail;
import java.util.regex.Pattern;
/**
* Validates an email address according to RFC 2822, using regular expressions.
*
* From the original author:
*
If you use this code, please keep the author information in tact and reference my site at leshazlewood.com. Thanks!
*
* Code sanitized by Benny Bottema (kept validation 100% in tact).
*
* @author Les Hazlewood, Benny Bottema
* @see EmailAddressValidationCriteria
*/
public final class EmailValidationUtil {
/**
* Private constructor; this is a utility class with static methods only, not designed for extension.
*/
private EmailValidationUtil() {
//
}
/**
* Validates an e-mail with default validation flags that remains true to RFC 2822. This means allowing both domain
* literals and quoted identifiers.
*
* @param email A complete email address.
* @return Whether the e-mail address is compliant with RFC 2822.
* @see EmailAddressValidationCriteria#EmailAddressValidationCriteria(boolean, boolean)
*/
public static boolean isValid(final String email) {
return isValid(email, new EmailAddressValidationCriteria(true, true));
}
/**
* Validates an e-mail with given validation flags.
*
* @param email A complete email address.
* @param emailAddressValidationCriteria A set of flags that restrict or relax RFC 2822 compliance.
* @return Whether the e-mail address is compliant with RFC 2822, configured using the passed in {@link EmailAddressValidationCriteria}.
* @see EmailAddressValidationCriteria#EmailAddressValidationCriteria(boolean, boolean)
*/
public static boolean isValid(final String email, final EmailAddressValidationCriteria emailAddressValidationCriteria) {
return buildValidEmailPattern(emailAddressValidationCriteria).matcher(email).matches();
}
protected static Pattern buildValidEmailPattern(EmailAddressValidationCriteria parameterObject) {
// RFC 2822 2.2.2 Structured Header Field Bodies
final String wsp = "[ \\t]"; // space or tab
final String fwsp = wsp + "*";
// RFC 2822 3.2.1 Primitive tokens
final String dquote = "\\\"";
// ASCII Control characters excluding white space:
final String noWsCtl = "\\x01-\\x08\\x0B\\x0C\\x0E-\\x1F\\x7F";
// all ASCII characters except CR and LF:
final String asciiText = "[\\x01-\\x09\\x0B\\x0C\\x0E-\\x7F]";
// RFC 2822 3.2.2 Quoted characters:
// single backslash followed by a text char
final String quotedPair = "(\\\\" + asciiText + ")";
// RFC 2822 3.2.4 Atom:
final String atext = "[a-zA-Z0-9\\!\\#\\$\\%\\&\\'\\*\\+\\-\\/\\=\\?\\^\\_\\`\\{\\|\\}\\~]";
final String atom = fwsp + atext + "+" + fwsp;
final String dotAtomText = atext + "+" + "(" + "\\." + atext + "+)*";
final String dotAtom = fwsp + "(" + dotAtomText + ")" + fwsp;
// RFC 2822 3.2.5 Quoted strings:
// noWsCtl and the rest of ASCII except the doublequote and backslash characters:
final String qtext = "[" + noWsCtl + "\\x21\\x23-\\x5B\\x5D-\\x7E]";
final String qcontent = "(" + qtext + "|" + quotedPair + ")";
final String quotedString = dquote + "(" + fwsp + qcontent + ")*" + fwsp + dquote;
// RFC 2822 3.2.6 Miscellaneous tokens
final String word = "((" + atom + ")|(" + quotedString + "))";
final String phrase = word + "+"; // one or more words.
// RFC 1035 tokens for domain names:
final String letter = "[a-zA-Z]";
final String letDig = "[a-zA-Z0-9]";
final String letDigHyp = "[a-zA-Z0-9-]";
final String rfcLabel = letDig + "(" + letDigHyp + "{0,61}" + letDig + ")?";
final String rfc1035DomainName = rfcLabel + "(\\." + rfcLabel + ")*\\." + letter + "{2,6}";
// RFC 2822 3.4 Address specification
// domain text - non white space controls and the rest of ASCII chars not including [, ], or \:
final String dtext = "[" + noWsCtl + "\\x21-\\x5A\\x5E-\\x7E]";
final String dcontent = dtext + "|" + quotedPair;
final String domainLiteral = "\\[" + "(" + fwsp + dcontent + "+)*" + fwsp + "\\]";
final String rfc2822Domain = "(" + dotAtom + "|" + domainLiteral + ")";
final String domain = parameterObject.isAllowDomainLiterals() ? rfc2822Domain : rfc1035DomainName;
final String localPart = "((" + dotAtom + ")|(" + quotedString + "))";
final String addrSpec = localPart + "@" + domain;
final String angleAddr = "<" + addrSpec + ">";
final String nameAddr = "(" + phrase + ")?" + fwsp + angleAddr;
final String mailbox = nameAddr + "|" + addrSpec;
// now compile a pattern for efficient re-use:
// if we're allowing quoted identifiers or not:
final String patternString = parameterObject.isAllowQuotedIdentifiers() ? mailbox : addrSpec;
return Pattern.compile(patternString);
}
}