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17 package org.apache.commons.validator;
18
19 import org.apache.oro.text.perl.Perl5Util;
20
21 /***
22 * <p>Perform email validations.</p>
23 * <p>
24 * This class is a Singleton; you can retrieve the instance via the getInstance() method.
25 * </p>
26 * <p>
27 * Based on a script by <a href="mailto:stamhankar@hotmail.com">Sandeep V. Tamhankar</a>
28 * http://javascript.internet.com
29 * </p>
30 * <p>
31 * This implementation is not guaranteed to catch all possible errors in an email address.
32 * For example, an address like nobody@noplace.somedog will pass validator, even though there
33 * is no TLD "somedog"
34 * </p>.
35 *
36 * @version $Revision: 478560 $ $Date: 2006-11-23 13:09:27 +0000 (Thu, 23 Nov 2006) $
37 * @since Validator 1.1
38 */
39 public class EmailValidator {
40
41 private static final String SPECIAL_CHARS = "//000-//037//(//)<>@,;:'//////\"//.//[//]//177";
42 private static final String VALID_CHARS = "[^//s" + SPECIAL_CHARS + "]";
43 private static final String QUOTED_USER = "(\"[^\"]*\")";
44 private static final String ATOM = VALID_CHARS + '+';
45 private static final String WORD = "((" + VALID_CHARS + "|')+|" + QUOTED_USER + ")";
46
47
48 private static final String LEGAL_ASCII_PATTERN = "/^[//000-//177]+$/";
49 private static final String EMAIL_PATTERN = "/^(.+)@(.+)$/";
50 private static final String IP_DOMAIN_PATTERN =
51 "/^//[(//d{1,3})[.](//d{1,3})[.](//d{1,3})[.](//d{1,3})//]$/";
52 private static final String TLD_PATTERN = "/^([a-zA-Z]+)$/";
53
54 private static final String USER_PATTERN = "/^//s*" + WORD + "(//." + WORD + ")*$/";
55 private static final String DOMAIN_PATTERN = "/^" + ATOM + "(//." + ATOM + ")*//s*$/";
56 private static final String ATOM_PATTERN = "/(" + ATOM + ")/";
57
58 /***
59 * Singleton instance of this class.
60 */
61 private static final EmailValidator EMAIL_VALIDATOR = new EmailValidator();
62
63 /***
64 * Returns the Singleton instance of this validator.
65 * @return singleton instance of this validator.
66 */
67 public static EmailValidator getInstance() {
68 return EMAIL_VALIDATOR;
69 }
70
71 /***
72 * Protected constructor for subclasses to use.
73 */
74 protected EmailValidator() {
75 super();
76 }
77
78 /***
79 * <p>Checks if a field has a valid e-mail address.</p>
80 *
81 * @param email The value validation is being performed on. A <code>null</code>
82 * value is considered invalid.
83 * @return true if the email address is valid.
84 */
85 public boolean isValid(String email) {
86 if (email == null) {
87 return false;
88 }
89
90 Perl5Util matchAsciiPat = new Perl5Util();
91 if (!matchAsciiPat.match(LEGAL_ASCII_PATTERN, email)) {
92 return false;
93 }
94
95 email = stripComments(email);
96
97
98 Perl5Util emailMatcher = new Perl5Util();
99 if (!emailMatcher.match(EMAIL_PATTERN, email)) {
100 return false;
101 }
102
103 if (email.endsWith(".")) {
104 return false;
105 }
106
107 if (!isValidUser(emailMatcher.group(1))) {
108 return false;
109 }
110
111 if (!isValidDomain(emailMatcher.group(2))) {
112 return false;
113 }
114
115 return true;
116 }
117
118 /***
119 * Returns true if the domain component of an email address is valid.
120 * @param domain being validatied.
121 * @return true if the email address's domain is valid.
122 */
123 protected boolean isValidDomain(String domain) {
124 boolean symbolic = false;
125 Perl5Util ipAddressMatcher = new Perl5Util();
126
127 if (ipAddressMatcher.match(IP_DOMAIN_PATTERN, domain)) {
128 if (!isValidIpAddress(ipAddressMatcher)) {
129 return false;
130 } else {
131 return true;
132 }
133 } else {
134
135 Perl5Util domainMatcher = new Perl5Util();
136 symbolic = domainMatcher.match(DOMAIN_PATTERN, domain);
137 }
138
139 if (symbolic) {
140 if (!isValidSymbolicDomain(domain)) {
141 return false;
142 }
143 } else {
144 return false;
145 }
146
147 return true;
148 }
149
150 /***
151 * Returns true if the user component of an email address is valid.
152 * @param user being validated
153 * @return true if the user name is valid.
154 */
155 protected boolean isValidUser(String user) {
156 Perl5Util userMatcher = new Perl5Util();
157 return userMatcher.match(USER_PATTERN, user);
158 }
159
160 /***
161 * Validates an IP address. Returns true if valid.
162 * @param ipAddressMatcher Pattren matcher
163 * @return true if the ip address is valid.
164 */
165 protected boolean isValidIpAddress(Perl5Util ipAddressMatcher) {
166 for (int i = 1; i <= 4; i++) {
167 String ipSegment = ipAddressMatcher.group(i);
168 if (ipSegment == null || ipSegment.length() <= 0) {
169 return false;
170 }
171
172 int iIpSegment = 0;
173
174 try {
175 iIpSegment = Integer.parseInt(ipSegment);
176 } catch(NumberFormatException e) {
177 return false;
178 }
179
180 if (iIpSegment > 255) {
181 return false;
182 }
183
184 }
185 return true;
186 }
187
188 /***
189 * Validates a symbolic domain name. Returns true if it's valid.
190 * @param domain symbolic domain name
191 * @return true if the symbolic domain name is valid.
192 */
193 protected boolean isValidSymbolicDomain(String domain) {
194 String[] domainSegment = new String[10];
195 boolean match = true;
196 int i = 0;
197 Perl5Util atomMatcher = new Perl5Util();
198 while (match) {
199 match = atomMatcher.match(ATOM_PATTERN, domain);
200 if (match) {
201 domainSegment[i] = atomMatcher.group(1);
202 int l = domainSegment[i].length() + 1;
203 domain =
204 (l >= domain.length())
205 ? ""
206 : domain.substring(l);
207
208 i++;
209 }
210 }
211
212 int len = i;
213
214
215 if (len < 2) {
216 return false;
217 }
218
219
220
221 String tld = domainSegment[len - 1];
222 if (tld.length() > 1) {
223 Perl5Util matchTldPat = new Perl5Util();
224 if (!matchTldPat.match(TLD_PATTERN, tld)) {
225 return false;
226 }
227 } else {
228 return false;
229 }
230
231 return true;
232 }
233 /***
234 * Recursively remove comments, and replace with a single space. The simpler
235 * regexps in the Email Addressing FAQ are imperfect - they will miss escaped
236 * chars in atoms, for example.
237 * Derived From Mail::RFC822::Address
238 * @param emailStr The email address
239 * @return address with comments removed.
240 */
241 protected String stripComments(String emailStr) {
242 String input = emailStr;
243 String result = emailStr;
244 String commentPat = "s/^((?:[^\"////]|////.)*(?:\"(?:[^\"////]|////.)*\"(?:[^\"////]|\111111////.)*)*)//((?:[^()////]|////.)*//)/$1 /osx";
245 Perl5Util commentMatcher = new Perl5Util();
246 result = commentMatcher.substitute(commentPat,input);
247
248 while (!result.equals(input)) {
249 input = result;
250 result = commentMatcher.substitute(commentPat,input);
251 }
252 return result;
253
254 }
255 }