1 /*
2 * To change this license header, choose License Headers in Project Properties.
3 * To change this template file, choose Tools | Templates
4 * and open the template in the editor.
5 */
6 package us.johnmeyer.utilities;
7
8 import java.net.URL;
9 import java.net.HttpURLConnection;
10 import org.apache.commons.validator.routines.UrlValidator;
11
12 /**
13 * Immutable {@link java.net.URL} wrapper. Provides URL syntax validation using
14 * Apache Commons validator code.
15 *
16 * <p>Used due to URL's validator not being as good as Apache's, and to avoid
17 * providing validation for each method that consumes a URL.</p>
18 */
19
20 public final class UrlWrapper {
21 /* TECHNICAL NOTE
22 * <p>There are many java.net.URL methods
23 * that can be further wrapped, for example, to support connectivity or
24 * to decompose the URL. These methods are left for future implementation.</p>
25 *
26 */
27
28 /** List of HTTP reponse status codes.
29 */
30 public enum Status {
31
32 /* TECHNICAL NOTE this is a subset of the status
33 codes and system will retunr UNSUPPORTED if it
34 encounters a code not on this list.
35
36 HttpURLConnection References are to java library
37 constants, also
38 a subset.*/
39
40 /** No problem.*/
41 OK(HttpURLConnection.HTTP_OK),
42
43 /** Unsupported status -- the status code is not
44 * being tracked in the code.
45 */
46 UNSUPPORTED(-1),
47
48 /** No Server was found or hostname not found in DNS. */
49 UNKNOWN_HOST(-1),
50
51 /** Could not find doc.*/
52 NOT_FOUND(HttpURLConnection.HTTP_NOT_FOUND);
53
54 /** Numeric code depicting http status, e.g. 404 */
55 private int code;
56
57 /** Text 'reason' explanation for http status. By default
58 * this is the name of the enumeration element.
59 */
60 private String reason;
61
62 /** Constructor.
63 *
64 * @param codeParam numeric code of http status.
65 */
66 Status(final int codeParam) {
67
68 this.code = codeParam;
69 if (codeParam != -1) {
70 this.reason = "HTTP_" + this.toString();
71 } else {
72 this.reason = this.toString();
73 }
74
75 }
76
77 /**
78 * Numeric code depicting http status, e.g. 404
79 * @return the code
80 */
81 public int getCode() {
82 return code;
83 }
84
85 /**
86 * Text 'reason' explanation for http status.
87 * @return the reason
88 */
89 public String getReason() {
90 return reason;
91 }
92
93 }
94
95 /** Holds URL persistently. */
96 private URL url;
97
98 /** Private constructor requires factory construction.
99 *
100 * @param urlParam URL to be wrapped
101 */
102 private UrlWrapper(final URL urlParam) {
103
104 this.url = urlParam;
105
106 }
107
108
109 /** Returns UrlWrapper instance. Checks validity of URL syntax.
110 *
111 * @param urlStringParam Url to create
112 *
113 * @return a wrapped URL
114 *
115 * @throws IllegalArgumentException if URL is invalid.
116 */
117
118 public static UrlWrapper newUrlWrapper(final String urlStringParam) {
119
120 URL url = toValidatedUrl(urlStringParam);
121 String assertUrlString = url.toExternalForm();
122
123 if (url == null) {
124 throw new IllegalArgumentException("Param " + urlStringParam
125 + " output is null.");
126 }
127
128
129 //verify URL output matches String input
130 if (!urlStringParam.equals(assertUrlString)) {
131 throw new IllegalStateException("String input " + urlStringParam
132 + " java.net.URL output " + assertUrlString
133 + ". Match input syntax to this output.");
134 }
135
136
137
138 return new UrlWrapper(url);
139
140 }
141
142 /**
143 * Converts String into URL. Checks validity of URL syntax using Apache
144 * Commons validation routine
145 * {@link org.apache.commons.validator.routines.UrlValidator}.
146 *
147 * @param newUrl URL to validate
148 *
149 * @return syntax-validated URL
150 *
151 * @throws IllegalArgumentException if URL is not valid or
152 if java.net.UrlWrapper returns malformed URL exception.
153 */
154 private static java.net.URL toValidatedUrl(final String newUrl) {
155
156 UrlValidator urlValidator = new UrlValidator();
157
158 URL returnUrl;
159
160 String invalidMessage
161 = " (URL) is invalid per "
162 + "org.apache.commons.validator.routines.UrlValidator.";
163
164 if (!urlValidator.isValid(newUrl)) {
165
166 String validationIssue = newUrl
167 + invalidMessage;
168
169 throw new IllegalArgumentException(validationIssue);
170
171 }
172
173 try {
174 returnUrl = new URL(newUrl);
175 } catch (java.net.MalformedURLException m) {
176
177 throw new IllegalArgumentException(m.getMessage());
178
179 }
180
181 return returnUrl;
182
183 }
184
185 /**
186 * Checks String if it is a valid URL.
187 *
188 * @param urlParam URL to check
189 *
190 * @return true if String is valid URL
191 */
192 public static boolean isValidUrl(final String urlParam) {
193
194 try {
195
196 UrlWrapper urlWrapper = UrlWrapper.newUrlWrapper(urlParam);
197
198 return true;
199
200 } catch (IllegalArgumentException e) {
201
202 return false;
203 }
204
205 }
206
207 /**Returns pre-validated URL.
208 *
209 * @return immutable java.net.URL value validated at instantiation.
210 */
211 public URL getUrl() {
212
213 return url;
214
215 }
216
217 /**Provides cleartext value.
218 *
219 * @return pre-validated URL as String.
220 */
221 public String toString() {
222 return url.toExternalForm();
223 }
224
225
226 /** Returns http status response.
227 *
228 * @return remote server-reported or network-reported status of this URL
229 *
230 * @throws java.io.IOException on any input/output error
231 */
232 public Status getResponse() throws java.io.IOException {
233
234 Integer responseCode = null;
235 Status statusLocal = null;
236 StringBuilder builder = new StringBuilder();
237 HttpURLConnection connection;
238
239 /* This typecast is really the only way to do this. It's the way
240 the class was designed, as there is now way to retrieve the
241 HTTPURLConnection directly from a connection.*/
242
243 connection = (HttpURLConnection) url.openConnection();
244
245 try {
246 responseCode = connection.getResponseCode();
247 } catch (java.net.UnknownHostException e) {
248 statusLocal = Status.UNKNOWN_HOST;
249 } catch (java.io.IOException e) {
250 e.printStackTrace();
251 statusLocal = Status.UNSUPPORTED;
252 }
253
254
255 if (statusLocal == null) {
256
257 for (Status status : Status.values()) {
258 if (status.getCode() == responseCode) {
259 statusLocal = status;
260 break;
261 }
262 }
263
264 if (statusLocal == null) {
265
266 statusLocal = Status.UNSUPPORTED;
267 }
268
269 }
270
271 return statusLocal;
272 }
273
274 }