Locales


1   /*
2    * Copyright (C) 2003  Christian Cryder [christianc@granitepeaks.com]
3    *
4    * This library is free software; you can redistribute it and/or
5    * modify it under the terms of the GNU Lesser General Public
6    * License as published by the Free Software Foundation; either
7    * version 2.1 of the License, or (at your option) any later version.
8    *
9    * This library is distributed in the hope that it will be useful,
10   * but WITHOUT ANY WARRANTY; without even the implied warranty of
11   * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
12   * Lesser General Public License for more details.
13   *
14   * You should have received a copy of the GNU Lesser General Public
15   * License along with this library; if not, write to the Free Software
16   * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
17   *
18   * $Id: Locales.java,v 1.5 2004/02/01 05:16:28 christianc Exp $
19   */
20  package org.enhydra.barracuda.plankton.l10n;
21  
22  import java.util.*;
23  import javax.servlet.*;
24  import javax.servlet.http.*;
25  
26  import org.apache.log4j.*;
27  
28  import org.enhydra.barracuda.plankton.http.*;
29  
30  
31  /**
32   * Simple locale utilities. This class makes it easy to determine the target
33   * locale from an event context or a servlet request. You can also set the locale
34   * and ask the class to save the information for you (in a cookie and/or the
35   * session) so that the locale info will persist across muliple requests
36   */
37  public class Locales {
38  
39      //default param names
40      public static String   LANGAUGE_KEY = "$loc_lang";
41      public static String   COUNTRY_KEY = "$loc_cntry";
42      public static String   VARIANT_KEY = "$loc_var";
43  
44      //persistance options
45      public static final int NONE = 0;
46      public static final int SESSION = 1;
47      public static final int COOKIES_AND_SESSION = 2;
48  
49      //default persistance option
50      public static int PERSIST_DEFAULT = SESSION;
51  
52      protected static final Logger logger = Logger.getLogger(Locales.class.getName());
53      private static final String   LOCALE = Localize.class.getName()+".Locale";
54  
55      /**
56       * Get the client locale from a ServletRequest using the default
57       * param keys and persist option
58       *
59       * @param req the HttpServletRequest from which we'd like to determine Locale
60       * @param resp the HttpServletResponse (needed if we want to save Locale in a cookie
61       *        otherwise it may be null)
62       * @return the target client Locale
63       */
64      public static Locale getClientLocale(HttpServletRequest req, HttpServletResponse resp) {
65          return getClientLocale(req, resp, LANGAUGE_KEY, COUNTRY_KEY, VARIANT_KEY, PERSIST_DEFAULT);
66      }
67  
68      /**
69       * This method attempts to get the client locale.
70       *
71       * <p>First we look to see if we can determine the locale by the req's
72       * form parameters (language, country, variant). If not, we look in
73       * the session to see if we can get the information from there. If
74       * that fails, we see if we can get the information from a client
75       * cookie (where the value is a comma delimited string containing
76       * language, country, and variant. If we still haven't got the locale
77       * information, we try and retrieve it from the servlet request, and
78       * if that fails, we use the default locale.
79       *
80       * <p>In each of these cases we save (depending on persistOption) the
81       * locale info in both the session and in a client cookie (so as to
82       * speed lookups on subsequent requests).
83       *
84       * @param req the HttpServletRequest from which we'd like to determine Locale
85       * @param resp the HttpServletResponse (needed if we want to save Locale in a cookie
86       *        otherwise it may be null)
87       * @param languageKey the key to be used to look in the request for a
88       *        language paramter
89       * @param countryKey the key to be used to look in the request for a
90       *        country paramter
91       * @param variantKey the key to be used to look in the request for a
92       *        variant paramter
93       * @param persistOption how we'd like to persist the Locale (by default, it will be stored
94       *        in the SESSION)
95       * @return the target client Locale
96       */
97      public static Locale getClientLocale(HttpServletRequest req, HttpServletResponse resp, String   languageKey, String   countryKey, String   variantKey, int persistOption) {
98          Locale loc = null;
99          if (req!=null) {
100             //first look for manual form parameters; if we find it here
101             //be sure to store the locale both as a cookie and in the session
102             if (loc==null) {
103                 String   language = req.getParameter(languageKey);
104                 String   country = req.getParameter(countryKey);
105                 String   variant = req.getParameter(variantKey);
106                 if (language!=null) {
107                     if (logger.isDebugEnabled()) logger.debug("Found locale in req params");
108                     loc = getLocale(language, country, variant);
109                     saveClientLocale(req, resp, loc, persistOption);
110                 }
111             }
112 
113             //next look in the session to see if we can find it there; if so,
114             //make sure we save it as a cookie too
115             if (loc==null && persistOption>=SESSION) {
116                 HttpSession session = SessionServices.getSession(req);
117                 if (session!=null) {
118                     if (logger.isDebugEnabled()) logger.debug("Found locale in session");
119                     loc = (Locale) session.getAttribute(LOCALE);
120                     saveClientLocale(req, resp, loc, persistOption);
121                 }
122             }
123 
124             //next see if there is a locale cookie; if there is,
125             //make sure we set the locale in the session as well
126             if (loc==null && persistOption>=COOKIES_AND_SESSION) {
127                 Cookie[] cookies = req.getCookies();
128                 if (cookies!=null) {
129                     for (int i=0, max=cookies.length; i<max; i++) {
130                         if (cookies[i].getName().equals(LOCALE)) {
131                             if (logger.isDebugEnabled()) logger.debug("Found locale in cookie");
132                             loc = readLocaleFromCookie(cookies[i]);
133                             saveClientLocale(req, resp, loc, persistOption);
134                         }
135                     }
136                 }
137             }
138 
139             //if we still haven't found a locale, look for it in the servlet
140             //request; be sure to store the locale both as a cookie and in
141             //the session
142             if (loc==null) {
143                 if (logger.isDebugEnabled()) logger.debug("Getting it from servlet request");
144                 loc = req.getLocale();
145                 saveClientLocale(req, resp, loc, persistOption);
146             }
147         }
148         //finally as a last resort, create a default locale; be sure to
149         //store the locale both as a cookie and in the session
150         if (loc==null) {
151             if (logger.isDebugEnabled()) logger.debug("Finding default locale");
152             loc = Locale.getDefault();
153             saveClientLocale(req, resp, loc, persistOption);
154         }
155         if (logger.isDebugEnabled()) logger.debug("return locale "+loc);
156         return loc;
157     }
158 
159     private static Locale getLocale(String   language, String   country, String   variant) {
160         Locale locale = null;
161         if (language!=null) {
162             if (country==null) country = "";
163             if (variant!=null) locale = new Locale(language, country, variant);
164             else locale = new Locale(language, country);
165         }
166         return locale;
167     }
168 
169 
170     private static Locale readLocaleFromCookie(Cookie cookie) {
171         String   value = cookie.getValue();
172         String   language = null;
173         String   country = null;
174         String   variant = null;
175         StringTokenizer st = new StringTokenizer(value,",");
176         if (st.hasMoreTokens()) language = st.nextToken();
177         if (st.hasMoreTokens()) country = st.nextToken();
178         if (st.hasMoreTokens()) variant = st.nextToken();
179         Locale locale = getLocale(language, country, variant);
180         if (logger.isDebugEnabled()) logger.debug("Got locale "+locale+" from cookie! (value="+value+")");
181         return locale;
182     }
183 
184     private static void writeLocaleInSession(HttpServletRequest req, Locale locale) {
185         if (req==null) return;
186         HttpSession session = SessionServices.getSession(req);
187         if (locale!=null) session.setAttribute(LOCALE, locale);
188         else session.removeAttribute(LOCALE);
189         if (logger.isDebugEnabled()) logger.debug("updated locale: "+locale+" in session!");
190     }
191 
192     private static void writeLocaleInCookie(HttpServletResponse resp, Locale locale) {
193         if (resp==null) return;
194         String   value = null;
195         if (locale!=null) value = locale.getLanguage()+","+locale.getCountry()+","+locale.getVariant();
196         Cookie cookie = new Cookie(LOCALE, value);
197         cookie.setMaxAge(locale!=null ? Integer.MAX_VALUE : 0);
198         resp.addCookie(cookie);
199         if (logger.isDebugEnabled()) logger.debug("updated locale: "+locale+" in cookie!");
200     }
201 
202     /**
203      * Here we actually force a locale to be saved using the default
204      * persist option. It will be stored in a cookie and/or the session.
205      *
206      * @param req the HttpServletRequest (needed to get the HttpSession)
207      * @param resp the HttpServletResponse (needed if we want to save Locale
208      *        in a cookie otherwise it may be null)
209      * @param loc the target client locale we'd like to set
210      */
211     public static void saveClientLocale(HttpServletRequest req, HttpServletResponse resp, Locale loc) {
212         saveClientLocale(req, resp, loc, PERSIST_DEFAULT);
213     }
214 
215     /**
216      * Here we actually force a locale to be saved. It will be stored in
217      * a cookie and/or the session.
218      *
219      * @param req the HttpServletRequest (needed to get the HttpSession)
220      * @param resp the HttpServletResponse (needed if we want to save Locale
221      *        in a cookie otherwise it may be null)
222      * @param loc the target client locale we'd like to set
223      * @param persistOption the specific persistOption to be used
224      */
225     public static void saveClientLocale(HttpServletRequest req, HttpServletResponse resp, Locale loc, int persistOption) {
226         //save it in the session
227         if (persistOption>=SESSION) writeLocaleInSession(req, loc);
228 
229         //save it as a cookie
230         if (persistOption>=COOKIES_AND_SESSION) writeLocaleInCookie(resp, loc);
231     }
232 
233     /**
234      * Release a client locale (this effectively removes it from whereever
235      * it might have been persisted)
236      *
237      * @param req the HttpServletRequest (needed to get the HttpSession)
238      * @param resp the HttpServletResponse (needed if we want to clear Locale
239      *        from a cookie otherwise it may be null)
240      */
241     public static void releaseClientLocale(HttpServletRequest req, HttpServletResponse resp) {
242         releaseClientLocale(req, resp, PERSIST_DEFAULT);
243     }
244 
245     /**
246      * Release a client locale (this effectively removes it from whereever
247      * it might have been persisted)
248      *
249      * @param req the HttpServletRequest (needed to get the HttpSession)
250      * @param resp the HttpServletResponse (needed if we want to clear Locale
251      *        from a cookie otherwise it may be null)
252      * @param persistOption the specific persistOption to be used (this tells us
253      *        where the locale info needs to be removed from)
254      */
255     public static void releaseClientLocale(HttpServletRequest req, HttpServletResponse resp, int persistOption) {
256         //save it in the session
257         if (persistOption>=SESSION) writeLocaleInSession(req, null);
258 
259         //save it as a cookie
260         if (persistOption>=COOKIES_AND_SESSION) writeLocaleInCookie(resp, null);
261     }
262 
263     /**
264      * This utility function will run through a list of Locales
265      * and return the index of the locale that matches most closely.
266      * If none of them match whatsoever, return the defaultIndex
267      *
268      * @param targetLocale the target locale
269      * @param locales the array of locales to search
270      * @param defaultIndex the default index (if no match is found)
271      * @return the index of the closest matching locale
272      */
273     public static int findClosestLocale(Locale targetLocale, Locale[] locales, int defaultIndex) {
274         int match2 = -1;
275         int match1 = -1;
276 
277         for (int i=0, max=locales.length; i<max; i++) {
278             //if we find a direct match (language, country, variant) return immediately
279             if (targetLocale.equals(locales[i])) return i;
280 
281             //if we can match on 2, save a reference to the index
282             if (targetLocale.getLanguage().equals(locales[i].getLanguage()) &&
283                 targetLocale.getCountry().equals(locales[i].getCountry())) match2 = i;
284 
285             //if we just match on language, save a reference to the index
286             if (targetLocale.getLanguage().equals(locales[i].getLanguage())) match1 = i;
287         }
288         if (match2!=-1) return match2;
289         else if (match1!=-1) return match1;
290         else return defaultIndex;
291     }
292 
293 }
294
A to Z: JavaDoc & Examples Daily Java News & Articles Open Source Projects Open Source Codes Free Computer Books Remove Frame
Popular Tags