1 /*
2 * Title: LanguageDecoratorMapper
3 * Description:
4 *
5 * This software is published under the terms of the OpenSymphony Software
6 * License version 1.1, of which a copy has been included with this
7 * distribution in the LICENSE.txt file.
8 */
9
10 package com.opensymphony.module.sitemesh.mapper;
11
12 import com.opensymphony.module.sitemesh.Config;
13 import com.opensymphony.module.sitemesh.Decorator;
14 import com.opensymphony.module.sitemesh.DecoratorMapper;
15 import com.opensymphony.module.sitemesh.Page;
16
17 import javax.servlet.http.HttpServletRequest;
18 import java.io.File;
19 import java.util.HashMap;
20 import java.util.Iterator;
21 import java.util.Map;
22 import java.util.Properties;
23
24 /**
25 * The LanguageDecoratorMapper can determine the preferred language set in the
26 * browser requesting a page, and map to a suitable Decorator (using the
27 * "Accept-Language" HTTP header).
28 *
29 * <p>This can be useful for supplying different versions of the same content
30 * for different languages.</p>
31 *
32 * <p>When LanguageDecoratorMapper is in the chain, it will request the appropriate Decorator
33 * from its parent. It will then add an extention to the filename of the Decorator, and
34 * if that file exists it shall be used as the Decorator instead. For example, if the
35 * Decorator path is <code>/blah.jsp</code> and the detected preferred language is <code>en</code>,
36 * the path <code>/blah-en.jsp</code> shall be used.</p>
37 *
38 * <p>The language mappings are configured by passing properties with <code>match.</code> as a prefix.
39 * For example: 'match.en'=engl , 'match.nl'=dutch .</p>
40 *
41 * @author <a href="mailto:pathos@pandora.be">Mathias Bogaert</a>
42 *
43 * @see com.opensymphony.module.sitemesh.DecoratorMapper
44 */
45 public final class LanguageDecoratorMapper extends AbstractDecoratorMapper {
46 private Map map = null;
47
48 public void init(Config config, Properties properties, DecoratorMapper parent) throws InstantiationException {
49 super.init(config, properties, parent);
50 map = new HashMap();
51 initMap(properties);
52 }
53
54 public Decorator getDecorator(HttpServletRequest request, Page page) {
55 try {
56 Decorator result = null;
57 final Decorator d = super.getDecorator(request, page);
58 String path = modifyPath(d.getPage(), getExt(request.getHeader("Accept-Language")));
59
60 File decFile = new File(config.getServletContext().getRealPath(path));
61
62 if (decFile.isFile()) {
63 result = new DefaultDecorator(d.getName(), path, null) {
64 public String getInitParameter(String paramName) {
65 return d.getInitParameter(paramName);
66 }
67 };
68 }
69 return result == null ? super.getDecorator(request, page) : result;
70 }
71 catch (NullPointerException e) {
72 return super.getDecorator(request, page);
73 }
74 }
75
76 /** Get extention for the language. */
77 private String getExt(String acceptLanguage) {
78 Iterator i = map.entrySet().iterator();
79 while (i.hasNext()) {
80 Map.Entry entry = (Map.Entry) i.next();
81
82 // Get the first language (preferred one) in the header, and
83 // only check the first two chars (the acceptLanguage could be en-gb, but
84 // we don't support this for now).
85 if (acceptLanguage.substring(0, 2).equals(entry.getKey())) {
86 return (String) entry.getValue();
87 }
88
89 // When the user-agent has multiple accept-languages (separated by ;),
90 // these are ignored because the site creator may wish that if the
91 // preferred language is not supported, the page uses the default
92 // decorator (in the default language), and not in some other
93 // language given by the browser (most of them are specified by
94 // default at install).
95 }
96 return null;
97 }
98
99 /** Change /abc/def.jsp into /abc/def-XYZ.jsp */
100 private static String modifyPath(String path, String ext) {
101 int dot = path.indexOf('.');
102 if (dot > -1) {
103 return path.substring(0, dot) + '-' + ext + path.substring(dot);
104 }
105 else {
106 return path + '-' + ext;
107 }
108 }
109
110 /** Initialize language mappings. */
111 private void initMap(Properties props) {
112 Iterator i = props.entrySet().iterator();
113 while (i.hasNext()) {
114 Map.Entry entry = (Map.Entry) i.next();
115 String key = (String) entry.getKey();
116 if (key.startsWith("match.")) {
117 String match = key.substring(6);
118 map.put(match, entry.getValue());
119 }
120 }
121 }
122 }
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