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Java > Open Source Codes > org > displaytag > decorator > AutolinkColumnDecorator


1 /**
2  * Licensed under the Artistic License; you may not use this file
3  * except in compliance with the License.
4  * You may obtain a copy of the License at
5  *
6  * http://displaytag.sourceforge.net/license.html
7  *
8  * THIS PACKAGE IS PROVIDED "AS IS" AND WITHOUT ANY EXPRESS OR
9  * IMPLIED WARRANTIES, INCLUDING, WITHOUT LIMITATION, THE IMPLIED
10  * WARRANTIES OF MERCHANTIBILITY AND FITNESS FOR A PARTICULAR PURPOSE.
11  */
12 package org.displaytag.decorator;
13
14 import javax.servlet.jsp.PageContext JavaDoc;
15
16 import org.apache.commons.lang.ArrayUtils;
17 import org.apache.commons.lang.StringUtils;
18 import org.displaytag.properties.MediaTypeEnum;
19 import org.displaytag.util.TagConstants;
20
21
22 /**
23  * This takes the string that is passed in, and "auto-links" it, it turns email addresses into hyperlinks, and also
24  * turns things that looks like URLs into hyperlinks as well.
25  * @author Fabrizio Giustina
26  * @version $Revision: 989 $ ($Author: fgiust $)
27  */
28 public class AutolinkColumnDecorator implements DisplaytagColumnDecorator
29 {
30
31     /**
32      * Instance used for the "autolink" tag attribute.
33      */
34     public static final DisplaytagColumnDecorator INSTANCE = new AutolinkColumnDecorator();
35
36     /**
37      * "://".
38      */
39     private static final String JavaDoc URL_DELIM = "://"; //$NON-NLS-1$
40
41     /**
42      * Urls.
43      */
44     private static final String JavaDoc[] URLS_PREFIXES = //
45 new String JavaDoc[]{"http", "https", "ftp"}; //$NON-NLS-1$ //$NON-NLS-1$ //$NON-NLS-1$
46
47     /**
48      * @see org.displaytag.decorator.DisplaytagColumnDecorator#decorate(Object, PageContext, MediaTypeEnum)
49      */
50     public Object JavaDoc decorate(Object JavaDoc columnValue, PageContext JavaDoc pageContext, MediaTypeEnum media)
51     {
52
53         if (columnValue == null)
54         {
55             return null;
56         }
57         String JavaDoc work = columnValue.toString();
58
59         int urlBegin;
60         StringBuffer JavaDoc buffer = new StringBuffer JavaDoc();
61
62         // First check for email addresses.
63 while ((urlBegin = work.indexOf('@')) != -1)
64         {
65             int start = 0;
66             int end = work.length() - 1;
67
68             // scan backwards...
69 for (int j = urlBegin; j >= 0; j--)
70             {
71                 if (Character.isWhitespace(work.charAt(j)))
72                 {
73                     start = j + 1;
74                     break;
75                 }
76             }
77
78             // scan forwards...
79 for (int j = urlBegin; j <= end; j++)
80             {
81                 if (Character.isWhitespace(work.charAt(j)))
82                 {
83                     end = j - 1;
84                     break;
85                 }
86             }
87
88             String JavaDoc email = work.substring(start, end + 1);
89
90             buffer.append(work.substring(0, start)).append("<a HREF=\"mailto:") //$NON-NLS-1$
91 .append(email + "\">") //$NON-NLS-1$
92 .append(email).append("</a>"); //$NON-NLS-1$
93
94             if (end == work.length())
95             {
96                 work = TagConstants.EMPTY_STRING;
97             }
98             else
99             {
100                 work = work.substring(end + 1);
101             }
102         }
103
104         work = buffer.toString() + work;
105         buffer = new StringBuffer JavaDoc();
106
107         // Now check for urls...
108 while ((urlBegin = work.indexOf(URL_DELIM)) != -1)
109         {
110
111             // scan backwards...
112 int fullUrlBegin = urlBegin;
113             StringBuffer JavaDoc prefixBuffer = new StringBuffer JavaDoc(10);
114             for (int j = fullUrlBegin - 1; j >= 0; j--)
115             {
116                 if (Character.isWhitespace(work.charAt(j)))
117                 {
118                     fullUrlBegin = j + 1;
119                     break;
120                 }
121                 fullUrlBegin = j;
122                 prefixBuffer.append(work.charAt(j));
123             }
124
125             if (!ArrayUtils.contains(URLS_PREFIXES, StringUtils.reverse(prefixBuffer.toString())))
126             {
127
128                 buffer.append(work.substring(0, urlBegin + 3));
129                 work = work.substring(urlBegin + 3);
130                 continue;
131             }
132
133             int urlEnd = work.length();
134
135             // scan forwards...
136 for (int j = urlBegin; j < urlEnd; j++)
137             {
138                 if (Character.isWhitespace(work.charAt(j)))
139                 {
140                     urlEnd = j;
141                     break;
142                 }
143             }
144
145             String JavaDoc url = work.substring(fullUrlBegin, urlEnd);
146
147             buffer.append(work.substring(0, fullUrlBegin)).append("<a HREF=\"")//$NON-NLS-1$
148 .append(url).append("\">")//$NON-NLS-1$
149 .append(url).append("</a>"); //$NON-NLS-1$
150
151             if (urlEnd >= work.length())
152             {
153                 work = TagConstants.EMPTY_STRING;
154             }
155             else
156             {
157                 work = work.substring(urlEnd);
158             }
159         }
160
161         buffer.append(work);
162         return buffer.toString();
163     }
164
165 }
166
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