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Java > Open Source Codes > org > displaytag > localization > I18nJstlAdapter


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.localization;
13
14 import java.util.Locale JavaDoc;
15 import java.util.MissingResourceException JavaDoc;
16 import java.util.ResourceBundle JavaDoc;
17
18 import javax.servlet.http.HttpServletRequest JavaDoc;
19 import javax.servlet.jsp.PageContext JavaDoc;
20 import javax.servlet.jsp.jstl.core.Config;
21 import javax.servlet.jsp.jstl.fmt.LocalizationContext;
22 import javax.servlet.jsp.tagext.Tag JavaDoc;
23 import javax.servlet.jsp.tagext.TagSupport JavaDoc;
24
25 import org.apache.commons.logging.Log;
26 import org.apache.commons.logging.LogFactory;
27 import org.apache.taglibs.standard.tag.common.fmt.BundleSupport;
28 import org.displaytag.Messages;
29
30
31 /**
32  * JSTL implementation of a resource provider and locale resolver. It will make the <code>titleKey</code> attribute of
33  * column tag works the same as fmt:message's <code>key property</code>. This tag must be the descendant of a
34  * <code>fmt:bundle</code> tag in order to use the titleKey. This is just a shortcut, which makes
35  *
36  * <pre>
37  * &lt;display:column titleKey="bar"/>
38  * </pre>
39  *
40  * behave the same as
41  *
42  * <pre>
43  * &lt;c:set var="foo">
44  * &lt;fmt:message key="bar"/>
45  * &lt;/c:set>
46  * &lt;display:column title="${foo}"/>
47  * </pre>
48  *
49  * If you don't define either <code>titleKey</code> or <code>titleKey</code> property on your column, first the tag
50  * will attempt to look up the <code>property</code> property in your ResourceBundle. Failing that, it will fall back
51  * to the parent class's behavior of just using the property name.
52  * @author Fabrizio Giustina
53  * @version $Revision: 737 $ ($Author: fgiust $)
54  */
55 public class I18nJstlAdapter implements I18nResourceProvider, LocaleResolver
56 {
57
58     /**
59      * prefix/suffix for missing entries.
60      */
61     public static final String JavaDoc UNDEFINED_KEY = "???"; //$NON-NLS-1$
62
63     /**
64      * logger.
65      */
66     private static Log log = LogFactory.getLog(I18nJstlAdapter.class);
67
68     /**
69      * Instantiates a new I18nJstlAdapter. Throw a NoClassDefFound error if BundleSupport is not available.
70      */
71     public I18nJstlAdapter()
72     {
73         // this will check if BundleSupport is available
74 // if a NoClassDefFound error is thrown, the I18nJstlAdapter will not be used
75 BundleSupport.class.hashCode();
76     }
77
78     /**
79      * @see LocaleResolver#resolveLocale(HttpServletRequest)
80      */
81     public Locale JavaDoc resolveLocale(HttpServletRequest JavaDoc request)
82     {
83         Locale JavaDoc locale = (Locale JavaDoc) Config.get(request.getSession(), Config.FMT_LOCALE);
84         if (locale == null)
85         {
86             locale = request.getLocale();
87         }
88         return locale;
89     }
90
91     /**
92      * @see I18nResourceProvider#getResource(String, String, Tag, PageContext)
93      */
94     public String JavaDoc getResource(String JavaDoc resourceKey, String JavaDoc defaultValue, Tag JavaDoc tag, PageContext JavaDoc pageContext)
95     {
96
97         // if titleKey isn't defined either, use property
98 String JavaDoc key = (resourceKey != null) ? resourceKey : defaultValue;
99         String JavaDoc title = null;
100         ResourceBundle JavaDoc bundle = null;
101
102         // jakarta jstl implementation, there is no other way to get the bundle from the parent fmt:bundle tag
103 Tag JavaDoc bundleTag = TagSupport.findAncestorWithClass(tag, BundleSupport.class);
104         if (bundleTag != null)
105         {
106             BundleSupport parent = (BundleSupport) bundleTag;
107             if (key != null)
108             {
109                 String JavaDoc prefix = parent.getPrefix();
110                 if (prefix != null)
111                 {
112                     key = prefix + key;
113                 }
114             }
115             bundle = parent.getLocalizationContext().getResourceBundle();
116         }
117
118         // resin jstl implementation, more versatile (we don't need to look up resin classes)
119 if (bundle == null)
120         {
121             Object JavaDoc cauchoBundle = pageContext.getAttribute("caucho.bundle"); //$NON-NLS-1$
122 if (cauchoBundle != null && cauchoBundle instanceof LocalizationContext)
123             {
124                 bundle = ((LocalizationContext) cauchoBundle).getResourceBundle();
125
126                 // handle prefix just like resin does
127 String JavaDoc prefix = (String JavaDoc) pageContext.getAttribute("caucho.bundle.prefix"); //$NON-NLS-1$
128 if (prefix != null)
129                 {
130                     key = prefix + key;
131                 }
132             }
133         }
134
135         // standard jstl localizationContest
136 if (bundle == null)
137         {
138             // check for the localizationContext in applicationScope, set in web.xml
139 LocalizationContext localization = BundleSupport.getLocalizationContext(pageContext);
140
141             if (localization != null)
142             {
143                 bundle = localization.getResourceBundle();
144             }
145         }
146
147         if (bundle != null)
148         {
149             try
150             {
151                 title = bundle.getString(key);
152             }
153             catch (MissingResourceException JavaDoc e)
154             {
155                 log.debug(Messages.getString("Localization.missingkey", key)); //$NON-NLS-1$
156
157                 // if user explicitely added a titleKey we guess this is an error
158 if (resourceKey != null)
159                 {
160                     title = UNDEFINED_KEY + resourceKey + UNDEFINED_KEY;
161                 }
162             }
163         }
164
165         return title;
166     }
167 }
168
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