VIVO-12 NIHVIVO-4011 Provide config and GUI for selecting Locale

doc/install.html

@@ -651,10 +651,80 @@
                     </tr>
                     <tr>
                         <td colspan="2">
-                            An absolute file path, pointing to the root directory of the Harvester utility.
+                          Force VIVO to use a specific language or Locale instead of those 
-                            You must include the final slash.
+                          specified by the browser. 
+                          This affects RDF data retrieved from the model, if RDFService.languageFilter is true.  
+                          This also affects the text of pages that have been modified to support multiple languages. 
                         </td>
                     </tr>
+                    <tr class="odd_row">
+                        <td>
+                          languages.forceLocale
+                        </td>
+                        <td>
+                          en_US
+                        </td>
+                    </tr>
+
+                    <tr>
+                        <td colspan="2">
+                          A list of supported languages or Locales that the user may choose to
+                          use instead of the one specified by the browser. Selection images must
+                          be available in the i18n/images directory of the theme.
+                          This affects RDF data retrieved from the model, if RDFService.languageFilter is true.  
+                          This also affects the text of pages that have been modified to support multiple languages. 
+                        </td>
+                    </tr>
+                    <tr class="odd_row">
+                        <td>
+                          languages.selectableLocales
+                        </td>
+                        <td>
+                           en, es, fr_FR
+                        </td>
+                    </tr>
+
+                    <tr>
+                        <td colspan="2">
+                          <b>For developers only.</b>
+                          Defeat the Freemarker template cache, so each template
+                          is read from disk on each request. This permits developers to immediately
+                          see the effect of changes to the template. The default is <code>false</code>, which
+                          means that a cached copy of each template will be used for 60 seconds 
+                          before the disk is checked for a new version.
+                          <br/><b>Setting this option to "true" slows down VIVO performance.</b>
+                        </td>
+                    </tr>
+                    <tr class="odd_row">
+                        <td>
+                          developer.defeatFreemarkerCache
+                        </td>
+                        <td>
+                          false
+                        </td>
+                    </tr>
+
+                    <tr>
+                        <td colspan="2">
+                          <b>For developers only.</b>
+                          Defeat the cache of language-specific text strings,
+                          so the language file is read from disk on each request.
+                          This permits developers to immediately
+                          see the effect of changes to the text strings. 
+                          The default is <code>false</code>, which means that the language file is 
+                          read when VIVO starts up, or when a new theme is selected.
+                          <br/><b>Setting this option to "true" slows down VIVO performance.</b>
+                        </td>
+                    </tr>
+                    <tr class="odd_row">
+                        <td>
+                          developer.defeatI18nCache = true
+                        </td>
+                        <td>
+                          false
+                        </td>
+                    </tr>
+                    
                 </tbody>
             </table>
             <h3 id="deploy">VI. Compile and deploy</h3>

webapp/config/example.runtime.properties

@@ -119,3 +119,46 @@ proxy.eligibleTypeList = http://www.w3.org/2002/07/owl#Thing
 # header supplied by the browser.  Default is true if not set.
 #
 RDFService.languageFilter = true
+
+#
+# Force VIVO to use a specific language or Locale instead of those 
+# specified by the browser. This affects RDF data retrieved from the model, 
+# if RDFService.languageFilter is true. This also affects the text of pages
+# that have been modified to support multiple languages. 
+#
+# languages.forceLocale = en_US
+
+#
+# A list of supported languages or Locales that the user may choose to
+# use instead of the one specified by the browser. Selection images must
+# be available in the i18n/images directory of the theme. This affects 
+# RDF data retrieved from the model, if RDFService.languageFilter is true.  
+# This also affects the text of pages that have been modified to support 
+# multiple languages. 
+#
+# This should not be used with languages.forceLocale, which will override it.
+#
+# languages.selectableLocales = en, es, fr
+
+#
+# For developers only: Setting this option to "true" slows down VIVO performance.
+#
+# Defeat the Freemarker template cache, so each template is read from disk 
+# on each request. This permits developers to immediately see the effect of 
+# changes to the template. The default is <code>false</code>, which means 
+# that a cached copy of each template will be used for 60 seconds before 
+# the disk is checked for a new version.
+#
+# developer.defeatFreemarkerCache = true
+
+#
+# For developers only: Setting this option to "true" slows down VIVO performance.
+#
+# Defeat the cache of language-specific text strings, so the language file 
+# is read from disk on each request. This permits developers to immediately
+# see the effect of changes to the text strings. The default is 
+# <code>false</code>, which means that the language file is read when 
+# VIVO starts up, or when a new theme is selected.
+#
+# developer.defeatI18nCache = true
+

webapp/src/edu/cornell/mannlib/vitro/webapp/controller/freemarker/FreemarkerConfiguration.java

@@ -5,7 +5,6 @@ package edu.cornell.mannlib.vitro.webapp.controller.freemarker;
 import java.io.File;
 import java.io.IOException;
 import java.util.ArrayList;
-import java.util.Collection;
 import java.util.HashMap;
 import java.util.HashSet;
 import java.util.List;

webapp/src/edu/cornell/mannlib/vitro/webapp/i18n/I18n.java

@@ -200,7 +200,7 @@ public class I18n {
 			log.debug("Paths are '" + themeI18nPath + "' and '" + appI18nPath
 					+ "'");
 
-			return VivoResourceBundle.getBundle(bundleName, ctx, appI18nPath,
+			return VitroResourceBundle.getBundle(bundleName, ctx, appI18nPath,
 					themeI18nPath, this);
 		}
 

webapp/src/edu/cornell/mannlib/vitro/webapp/i18n/VitroResourceBundle.java

@@ -41,8 +41,8 @@ import org.apache.commons.logging.LogFactory;
  * 
  * In all_es.properties: account_email_html = @@file accountEmail_es.html
  */
-public class VivoResourceBundle extends ResourceBundle {
+public class VitroResourceBundle extends ResourceBundle {
-	private static final Log log = LogFactory.getLog(VivoResourceBundle.class);
+	private static final Log log = LogFactory.getLog(VitroResourceBundle.class);
 
 	private static final String FILE_FLAG = "@@file ";
 	private static final String MESSAGE_FILE_NOT_FOUND = "File {1} not found for property {0}.";
@@ -51,11 +51,11 @@ public class VivoResourceBundle extends ResourceBundle {
 	// Factory method
 	// ----------------------------------------------------------------------
 
-	public static VivoResourceBundle getBundle(String bundleName,
+	public static VitroResourceBundle getBundle(String bundleName,
 			ServletContext ctx, String appI18nPath, String themeI18nPath,
 			Control control) {
 		try {
-			return new VivoResourceBundle(bundleName, ctx, appI18nPath,
+			return new VitroResourceBundle(bundleName, ctx, appI18nPath,
 					themeI18nPath, control);
 		} catch (FileNotFoundException e) {
 			log.debug(e);
@@ -78,7 +78,7 @@ public class VivoResourceBundle extends ResourceBundle {
 	private final Properties defaults;
 	private final Properties properties;
 
-	private VivoResourceBundle(String bundleName, ServletContext ctx,
+	private VitroResourceBundle(String bundleName, ServletContext ctx,
 			String appI18nPath, String themeI18nPath, Control control)
 			throws IOException {
 		this.bundleName = bundleName;

webapp/src/edu/cornell/mannlib/vitro/webapp/i18n/selection/LocaleSelectionController.java

@@ -0,0 +1,100 @@
+/* $This file is distributed under the terms of the license in /doc/license.txt$ */
+
+package edu.cornell.mannlib.vitro.webapp.i18n.selection;
+
+import java.io.IOException;
+import java.util.List;
+import java.util.Locale;
+
+import javax.servlet.ServletException;
+import javax.servlet.http.HttpServlet;
+import javax.servlet.http.HttpServletRequest;
+import javax.servlet.http.HttpServletResponse;
+
+import org.apache.commons.lang.LocaleUtils;
+import org.apache.commons.lang.StringUtils;
+import org.apache.commons.logging.Log;
+import org.apache.commons.logging.LogFactory;
+
+import edu.cornell.mannlib.vitro.webapp.beans.DisplayMessage;
+import edu.cornell.mannlib.vitro.webapp.controller.freemarker.UrlBuilder;
+
+/**
+ * Call this at /selectLocale&selection=[locale_string]
+ * 
+ * For example: /selectLocale&selection=en_US or /selectLocale&selection=es
+ * 
+ * Write an error to the log (and to DisplayMessage) if the selection is not
+ * syntactically valid.
+ * 
+ * Write a warning to the log if the selection code is not one of the selectable
+ * Locales from runtime.properties, or if the selection code is not recognized
+ * by the system.
+ * 
+ * Set the new Locale in the Session using SelectedLocale and return to the
+ * referrer.
+ */
+public class LocaleSelectionController extends HttpServlet {
+	private static final Log log = LogFactory
+			.getLog(LocaleSelectionController.class);
+
+	public static final String PARAMETER_SELECTION = "selection";
+
+	@Override
+	protected void doGet(HttpServletRequest req, HttpServletResponse resp)
+			throws ServletException, IOException {
+		String referrer = req.getHeader("referer");
+
+		String selectedLocale = req.getParameter(PARAMETER_SELECTION);
+
+		try {
+			processSelectedLocale(req, selectedLocale);
+		} catch (Exception e) {
+			log.error("Failed to process the user's Locale selection", e);
+		}
+
+		if (StringUtils.isEmpty(referrer)) {
+			resp.sendRedirect(UrlBuilder.getHomeUrl());
+		} else {
+			resp.sendRedirect(referrer);
+		}
+	}
+
+	private void processSelectedLocale(HttpServletRequest req,
+			String selectedLocale) {
+		if (StringUtils.isBlank(selectedLocale)) {
+			log.debug("No '" + PARAMETER_SELECTION + "' parameter");
+			return;
+		}
+
+		Locale locale = null;
+
+		try {
+			locale = LocaleUtils.toLocale(selectedLocale.trim());
+			log.debug("Locale selection is " + locale);
+		} catch (IllegalArgumentException e) {
+			log.error("Failed to convert the selection to a Locale", e);
+			DisplayMessage.setMessage(req,
+					"There was a problem in the system. "
+							+ "Your language choice was rejected.");
+			return;
+		}
+
+		List<Locale> selectables = SelectedLocale.getSelectableLocales(req);
+		if (!selectables.contains(locale)) {
+			log.warn("User selected a locale '" + locale
+					+ "' that was not in the list: " + selectables);
+		} else if (!LocaleUtils.isAvailableLocale(locale)) {
+			log.warn("User selected an unrecognized locale: '" + locale + "'");
+		}
+
+		SelectedLocale.setSelectedLocale(req, locale);
+		log.debug("Setting selected locale to " + locale);
+	}
+
+	@Override
+	protected void doPost(HttpServletRequest req, HttpServletResponse resp)
+			throws ServletException, IOException {
+		doGet(req, resp);
+	}
+}

webapp/src/edu/cornell/mannlib/vitro/webapp/i18n/selection/LocaleSelectionDataGetter.java

@@ -0,0 +1,95 @@
+/* $This file is distributed under the terms of the license in /doc/license.txt$ */
+
+package edu.cornell.mannlib.vitro.webapp.i18n.selection;
+
+import java.io.FileNotFoundException;
+import java.util.ArrayList;
+import java.util.Collections;
+import java.util.HashMap;
+import java.util.List;
+import java.util.Locale;
+import java.util.Map;
+
+import org.apache.commons.logging.Log;
+import org.apache.commons.logging.LogFactory;
+
+import edu.cornell.mannlib.vitro.webapp.controller.VitroRequest;
+import edu.cornell.mannlib.vitro.webapp.controller.freemarker.UrlBuilder;
+import edu.cornell.mannlib.vitro.webapp.utils.dataGetter.DataGetter;
+
+/**
+ * Get the data for the selectable Locales, so the Freemarker template can
+ * create a row of flag images that will select the desired locale.
+ * 
+ * If there are no selectable Locales in runtime.properties, we return an empty
+ * map. (selectLocale?? will return false)
+ * 
+ * If the Locale has been forced by runtime.properties, we do the same.
+ * 
+ * If there are selectable Locales, the returned map will contain a structure
+ * like this:
+ * 
+ * <pre>
+ * {selectLocale={
+ *   selectLocaleUrl = [the URL for the form action to select a Locale]
+ *   locales={         [a list of maps]
+ *       {               [a map for each Locale]
+ *         code =          [the code for the Locale, e.g. "en_US"]
+ *         label =         [the alt text for the Locale, e.g. "Spanish (Spain)"]
+ *         imageUrl =      [the URL of the image that represents the Locale]
+ *       }
+ *     }  
+ *   }
+ * }
+ * </pre>
+ */
+public class LocaleSelectionDataGetter implements DataGetter {
+	private static final Log log = LogFactory
+			.getLog(LocaleSelectionDataGetter.class);
+
+	private final VitroRequest vreq;
+
+	public LocaleSelectionDataGetter(VitroRequest vreq) {
+		this.vreq = vreq;
+	}
+
+	@Override
+	public Map<String, Object> getData(Map<String, Object> valueMap) {
+		List<Locale> selectables = SelectedLocale.getSelectableLocales(vreq);
+		if (selectables.isEmpty()) {
+			return Collections.emptyMap();
+		}
+
+		Map<String, Object> result = new HashMap<String, Object>();
+		result.put("selectLocaleUrl", UrlBuilder.getUrl("/selectLocale"));
+		result.put("locales", buildLocalesList(selectables));
+
+		Map<String, Object> bodyMap = new HashMap<String, Object>();
+		bodyMap.put("selectLocale", result);
+		log.debug("Sending these values: " + bodyMap);
+		return bodyMap;
+	}
+
+	private List<Map<String, Object>> buildLocalesList(List<Locale> selectables) {
+		Locale currentLocale = SelectedLocale.getCurrentLocale(vreq);
+		List<Map<String, Object>> list = new ArrayList<Map<String, Object>>();
+		for (Locale locale : selectables) {
+			try {
+				list.add(buildLocaleMap(locale, currentLocale));
+			} catch (FileNotFoundException e) {
+				log.warn("Can't show the Locale selector for '" + locale
+						+ "': " + e);
+			}
+		}
+		return list;
+	}
+
+	private Map<String, Object> buildLocaleMap(Locale locale,
+			Locale currentLocale) throws FileNotFoundException {
+		Map<String, Object> map = new HashMap<String, Object>();
+		map.put("code", locale.toString());
+		map.put("label", locale.getDisplayName(currentLocale));
+		map.put("imageUrl", LocaleSelectorUtilities.getImageUrl(vreq, locale));
+		return map;
+	}
+}

webapp/src/edu/cornell/mannlib/vitro/webapp/i18n/selection/LocaleSelectionFilter.java

@@ -0,0 +1,113 @@
+/* $This file is distributed under the terms of the license in /doc/license.txt$ */
+
+package edu.cornell.mannlib.vitro.webapp.i18n.selection;
+
+import java.io.IOException;
+import java.util.Collections;
+import java.util.Enumeration;
+import java.util.List;
+import java.util.Locale;
+
+import javax.servlet.Filter;
+import javax.servlet.FilterChain;
+import javax.servlet.FilterConfig;
+import javax.servlet.ServletException;
+import javax.servlet.ServletRequest;
+import javax.servlet.ServletResponse;
+import javax.servlet.http.HttpServletRequest;
+import javax.servlet.http.HttpServletRequestWrapper;
+
+import org.apache.commons.collections.EnumerationUtils;
+import org.apache.commons.logging.Log;
+import org.apache.commons.logging.LogFactory;
+
+/**
+ * Check for a Locale in the ServletContext or the Session that should override
+ * the Locale in the ServletRequest.
+ * 
+ * If there is such a Locale, wrap the ServletRequest so it behaves as if that
+ * is the preferred Locale.
+ * 
+ * Otherwise, just process the request as usual.
+ */
+public class LocaleSelectionFilter implements Filter {
+	private static final Log log = LogFactory
+			.getLog(LocaleSelectionFilter.class);
+
+	@Override
+	public void init(FilterConfig filterConfig) throws ServletException {
+		// Nothing to do at startup.
+	}
+
+	@Override
+	public void destroy() {
+		// Nothing to do at shutdown.
+	}
+
+	@Override
+	public void doFilter(ServletRequest request, ServletResponse response,
+			FilterChain chain) throws IOException, ServletException {
+		if (request instanceof HttpServletRequest) {
+			HttpServletRequest hreq = (HttpServletRequest) request;
+
+			Locale overridingLocale = SelectedLocale.getOverridingLocale(hreq);
+			log.debug("overriding Locale is " + overridingLocale);
+
+			if (overridingLocale != null) {
+				request = new LocaleSelectionRequestWrapper(hreq,
+						overridingLocale);
+			}
+		} else {
+			log.debug("Not an HttpServletRequest.");
+		}
+		chain.doFilter(request, response);
+	}
+
+	// ----------------------------------------------------------------------
+	// Helper classes
+	// ----------------------------------------------------------------------
+
+	/**
+	 * Uses the selected Locale as the preferred Locale of the request.
+	 */
+	private static class LocaleSelectionRequestWrapper extends
+			HttpServletRequestWrapper {
+		private final HttpServletRequest request;
+		private final Locale selectedLocale;
+
+		public LocaleSelectionRequestWrapper(HttpServletRequest request,
+				Locale selectedLocale) {
+			super(request);
+
+			if (request == null) {
+				throw new NullPointerException("request may not be null.");
+			}
+			this.request = request;
+
+			if (selectedLocale == null) {
+				throw new NullPointerException(
+						"selectedLocale may not be null.");
+			}
+			this.selectedLocale = selectedLocale;
+		}
+
+		@Override
+		public Locale getLocale() {
+			return selectedLocale;
+		}
+
+		/**
+		 * Put the selected Locale on the front of the list of acceptable
+		 * Locales.
+		 */
+		@SuppressWarnings({ "unchecked", "rawtypes" })
+		@Override
+		public Enumeration getLocales() {
+			List list = EnumerationUtils.toList(request.getLocales());
+			list.remove(selectedLocale);
+			list.add(0, selectedLocale);
+			return Collections.enumeration(list);
+		}
+	}
+
+}

webapp/src/edu/cornell/mannlib/vitro/webapp/i18n/selection/LocaleSelectionSetup.java

@@ -0,0 +1,148 @@
+/* $This file is distributed under the terms of the license in /doc/license.txt$ */
+
+package edu.cornell.mannlib.vitro.webapp.i18n.selection;
+
+import java.util.ArrayList;
+import java.util.List;
+import java.util.Locale;
+
+import javax.servlet.ServletContext;
+import javax.servlet.ServletContextEvent;
+import javax.servlet.ServletContextListener;
+
+import org.apache.commons.lang.LocaleUtils;
+import org.apache.commons.lang.StringUtils;
+
+import edu.cornell.mannlib.vitro.webapp.config.ConfigurationProperties;
+import edu.cornell.mannlib.vitro.webapp.startup.StartupStatus;
+
+/**
+ * Check the ConfigurationProperties for a forced locale, or for a
+ * comma-separate list of selectable locales.
+ * 
+ * Create the appropriate Locale objects and store them in the ServletContext.
+ */
+public class LocaleSelectionSetup implements ServletContextListener {
+	/**
+	 * If this is set, the locale is forced. No selection will be offered to the
+	 * user, and browser locales will be ignored.
+	 */
+	public static final String PROPERTY_FORCE_LOCALE = "languages.forceLocale";
+
+	/**
+	 * This is the list of locales that the user may select. There should be a
+	 * national flag or symbol available for each supported locale.
+	 */
+	public static final String PROPERTY_SELECTABLE_LOCALES = "languages.selectableLocales";
+
+	private ServletContext ctx;
+	private StartupStatus ss;
+	private ConfigurationProperties props;
+
+	private String forceString;
+	private String selectableString;
+
+	@Override
+	public void contextInitialized(ServletContextEvent sce) {
+		ctx = sce.getServletContext();
+		ss = StartupStatus.getBean(ctx);
+		props = ConfigurationProperties.getBean(sce);
+
+		readProperties();
+
+		if (isForcing() && hasSelectables()) {
+			warnAboutOverride();
+		}
+
+		if (isForcing()) {
+			forceLocale();
+		} else if (hasSelectables()) {
+			setUpSelections();
+		} else {
+			reportNoLocales();
+		}
+	}
+
+	private void readProperties() {
+		forceString = props.getProperty(PROPERTY_FORCE_LOCALE, "");
+		selectableString = props.getProperty(PROPERTY_SELECTABLE_LOCALES, "");
+	}
+
+	private boolean isForcing() {
+		return StringUtils.isNotBlank(forceString);
+	}
+
+	private boolean hasSelectables() {
+		return StringUtils.isNotBlank(selectableString);
+	}
+
+	private void warnAboutOverride() {
+		ss.warning(this, "'" + PROPERTY_FORCE_LOCALE + "' will override '"
+				+ PROPERTY_SELECTABLE_LOCALES + "'.");
+	}
+
+	private void forceLocale() {
+		try {
+			Locale forceLocale = buildLocale(forceString);
+			SelectedLocale.setForcedLocale(ctx, forceLocale);
+			ssInfo("Setting forced locale to '" + forceLocale + "'.");
+		} catch (IllegalArgumentException e) {
+			ssWarning("Problem in '" + PROPERTY_FORCE_LOCALE + "': "
+					+ e.getMessage());
+		}
+	}
+
+	private void setUpSelections() {
+		List<Locale> locales = new ArrayList<Locale>();
+		for (String string : splitSelectables()) {
+			try {
+				locales.add(buildLocale(string));
+			} catch (IllegalArgumentException e) {
+				ssWarning("Problem in '" + PROPERTY_SELECTABLE_LOCALES + "': "
+						+ e.getMessage());
+			}
+		}
+
+		SelectedLocale.setSelectableLocales(ctx, locales);
+		ssInfo("Setting selectable locales to '" + locales + "'.");
+	}
+
+	private String[] splitSelectables() {
+		return selectableString.split("\\s*,\\s*");
+	}
+
+	private void reportNoLocales() {
+		ssInfo("There is no Locale information.");
+	}
+
+	private void ssInfo(String message) {
+		ss.info(this, message + showPropertyValues());
+	}
+
+	private void ssWarning(String message) {
+		ss.warning(this, message + showPropertyValues());
+	}
+
+	private String showPropertyValues() {
+		return " In runtime.properties, '" + PROPERTY_FORCE_LOCALE
+				+ "' is set to '" + forceString + "', '"
+				+ PROPERTY_SELECTABLE_LOCALES + "' is set to '"
+				+ selectableString + "'";
+	}
+
+	private Locale buildLocale(String localeString)
+			throws IllegalArgumentException {
+		Locale locale = LocaleUtils.toLocale(localeString);
+
+		if (!LocaleUtils.isAvailableLocale(locale)) {
+			ssWarning("'" + locale + "' is not a recognized locale.");
+		}
+		return locale;
+	}
+
+	@Override
+	public void contextDestroyed(ServletContextEvent arg0) {
+		// Nothing to do at shutdown.
+	}
+
+}

webapp/src/edu/cornell/mannlib/vitro/webapp/i18n/selection/LocaleSelectorUtilities.java

@@ -0,0 +1,54 @@
+/* $This file is distributed under the terms of the license in /doc/license.txt$ */
+
+package edu.cornell.mannlib.vitro.webapp.i18n.selection;
+
+import java.io.FileNotFoundException;
+import java.util.Locale;
+
+import javax.servlet.ServletContext;
+
+import org.apache.commons.logging.Log;
+import org.apache.commons.logging.LogFactory;
+
+import edu.cornell.mannlib.vitro.webapp.controller.VitroRequest;
+
+/**
+ * Some static methods for the GUI aspects of selecting a Locale.
+ */
+public class LocaleSelectorUtilities {
+	private static final Log log = LogFactory
+			.getLog(LocaleSelectorUtilities.class);
+
+	/**
+	 * Look in the current theme directory to find a selection image for this
+	 * Locale.
+	 * 
+	 * Images are expected at a resource path like
+	 * /[themeDir]/i18n/images/select_locale_[locale_code].*
+	 * 
+	 * For example, /themes/wilma/i18n/images/select_locale_en.png
+	 * /themes/wilma/i18n/images/select_locale_en.JPEG
+	 * /themes/wilma/i18n/images/select_locale_en.gif
+	 * 
+	 * To create a proper URL, prepend the context path.
+	 */
+	public static String getImageUrl(VitroRequest vreq, Locale locale)
+			throws FileNotFoundException {
+		String filename = "select_locale_" + locale + ".";
+
+		String themeDir = vreq.getAppBean().getThemeDir();
+		String imageDirPath = "/" + themeDir + "i18n/images/";
+
+		ServletContext ctx = vreq.getSession().getServletContext();
+		for (Object o : ctx.getResourcePaths(imageDirPath)) {
+			String resourcePath = (String) o;
+			if (resourcePath.contains(filename)) {
+				String fullPath = vreq.getContextPath() + resourcePath;
+				log.debug("Found image for " + locale + " at '" + fullPath
+						+ "'");
+				return fullPath;
+			}
+		}
+		throw new FileNotFoundException("Can't find an image for " + locale);
+	}
+}

webapp/src/edu/cornell/mannlib/vitro/webapp/i18n/selection/SelectedLocale.java

@@ -0,0 +1,204 @@
+/* $This file is distributed under the terms of the license in /doc/license.txt$ */
+
+package edu.cornell.mannlib.vitro.webapp.i18n.selection;
+
+import java.util.Collections;
+import java.util.List;
+import java.util.Locale;
+
+import javax.servlet.ServletContext;
+import javax.servlet.http.HttpServletRequest;
+import javax.servlet.http.HttpSession;
+
+import org.apache.commons.logging.Log;
+import org.apache.commons.logging.LogFactory;
+
+/**
+ * A utility class for storing and retrieving Locale information.
+ * 
+ * The static methods create beans and store them in the ServletContext or the
+ * session, where the information can be found later.
+ */
+public abstract class SelectedLocale {
+	private static final Log log = LogFactory.getLog(SelectedLocale.class);
+
+	/** Use this attribute on both the ServletContext and the Session. */
+	protected static final String ATTRIBUTE_NAME = "SELECTED_LOCALE";
+
+	/**
+	 * Store the forced locale in the servlet context. Clear any selectable
+	 * Locales.
+	 */
+	public static void setForcedLocale(ServletContext ctx, Locale forcedLocale) {
+		log.debug("Set forced locale: " + forcedLocale);
+		ctx.setAttribute(ATTRIBUTE_NAME,
+				new ContextSelectedLocale(forcedLocale));
+	}
+
+	/**
+	 * Store the selected locale in the current session.
+	 */
+	public static void setSelectedLocale(HttpServletRequest req,
+			Locale selectedLocale) {
+		log.debug("Set selected locale: " + selectedLocale);
+		req.getSession().setAttribute(ATTRIBUTE_NAME,
+				new SessionSelectedLocale(selectedLocale));
+	}
+
+	/**
+	 * Do we need to override the Locale in the current request? return the
+	 * first of these to be found:
+	 * <ul>
+	 * <li>The forced Locale in the servlet context</li>
+	 * <li>The selected Locale in the session</li>
+	 * <li>null</li>
+	 * </ul>
+	 */
+	public static Locale getOverridingLocale(HttpServletRequest req) {
+		HttpSession session = req.getSession();
+		ServletContext ctx = session.getServletContext();
+
+		Object ctxInfo = ctx.getAttribute(ATTRIBUTE_NAME);
+		if (ctxInfo instanceof ContextSelectedLocale) {
+			Locale forcedLocale = ((ContextSelectedLocale) ctxInfo)
+					.getForcedLocale();
+			if (forcedLocale != null) {
+				log.debug("Found forced locale in the context: " + forcedLocale);
+				return forcedLocale;
+			}
+		}
+
+		Object sessionInfo = session.getAttribute(ATTRIBUTE_NAME);
+		if (sessionInfo instanceof SessionSelectedLocale) {
+			Locale selectedLocale = ((SessionSelectedLocale) sessionInfo)
+					.getSelectedLocale();
+			if (selectedLocale != null) {
+				log.debug("Found selected locale in the session: "
+						+ selectedLocale);
+				return selectedLocale;
+			}
+		}
+
+		return null;
+	}
+
+	/**
+	 * Get the current Locale to use, which is the first of these to be found:
+	 * <ul>
+	 * <li>The forced Locale in the servlet context</li>
+	 * <li>The selected Locale in the session</li>
+	 * <li>The Locale from the request</li>
+	 * <li>The default Locale for the JVM</li>
+	 * </ul>
+	 */
+	public static Locale getCurrentLocale(HttpServletRequest req) {
+		Locale overridingLocale = getOverridingLocale(req);
+
+		if (overridingLocale != null) {
+			return overridingLocale;
+		}
+
+		Locale requestLocale = req.getLocale();
+		if (requestLocale != null) {
+			log.debug("Found locale in the request: " + requestLocale);
+			return requestLocale;
+		}
+
+		log.debug("Using default locale: " + Locale.getDefault());
+		return Locale.getDefault();
+	}
+
+	/**
+	 * Store a list of selectable Locales in the servlet context, so we can
+	 * easily build the selection panel in the GUI. Clears any forced locale.
+	 */
+	public static void setSelectableLocales(ServletContext ctx,
+			List<Locale> selectableLocales) {
+		log.debug("Setting selectable locales: " + selectableLocales);
+		ctx.setAttribute(ATTRIBUTE_NAME, new ContextSelectedLocale(
+				selectableLocales));
+	}
+
+	/**
+	 * Get the list of selectable Locales from the servlet context. May return
+	 * an empty list, but never returns null.
+	 */
+	public static List<Locale> getSelectableLocales(HttpServletRequest req) {
+		ServletContext ctx = req.getSession().getServletContext();
+		Object ctxInfo = ctx.getAttribute(ATTRIBUTE_NAME);
+		if (ctxInfo instanceof ContextSelectedLocale) {
+			List<Locale> selectableLocales = ((ContextSelectedLocale) ctxInfo)
+					.getSelectableLocales();
+			if (selectableLocales != null) {
+				log.debug("Returning selectable locales: " + selectableLocales);
+				return selectableLocales;
+			}
+		}
+
+		log.debug("No selectable locales were found. Returning an empty list.");
+		return Collections.emptyList();
+	}
+
+	// ----------------------------------------------------------------------
+	// Bean classes
+	// ----------------------------------------------------------------------
+
+	/** Holds Locale information in the ServletContext. */
+	protected static class ContextSelectedLocale {
+		// Only one of these is populated.
+		private final Locale forcedLocale;
+		private final List<Locale> selectableLocales;
+
+		public ContextSelectedLocale(Locale forcedLocale) {
+			if (forcedLocale == null) {
+				throw new NullPointerException("forcedLocale may not be null.");
+			}
+
+			this.forcedLocale = forcedLocale;
+			this.selectableLocales = Collections.emptyList();
+		}
+
+		public ContextSelectedLocale(List<Locale> selectableLocales) {
+			if (selectableLocales == null) {
+				selectableLocales = Collections.emptyList();
+			}
+
+			this.forcedLocale = null;
+			this.selectableLocales = selectableLocales;
+		}
+
+		public Locale getForcedLocale() {
+			return forcedLocale;
+		}
+
+		public List<Locale> getSelectableLocales() {
+			return selectableLocales;
+		}
+
+		@Override
+		public String toString() {
+			return "ContextSelectedLocale[forced=" + forcedLocale
+					+ ", selectable=" + selectableLocales + "]";
+		}
+
+	}
+
+	/** Holds Locale information in the Session. */
+	protected static class SessionSelectedLocale {
+		private final Locale selectedLocale;
+
+		public SessionSelectedLocale(Locale selectedLocale) {
+			this.selectedLocale = selectedLocale;
+		}
+
+		public Locale getSelectedLocale() {
+			return selectedLocale;
+		}
+
+		@Override
+		public String toString() {
+			return "SessionSelectedLocale[" + selectedLocale + "]";
+		}
+
+	}
+}

webapp/src/edu/cornell/mannlib/vitro/webapp/startup/StartupStatus.java

@@ -23,7 +23,7 @@ import org.apache.commons.logging.LogFactory;
 public class StartupStatus {
 	private static final Log log = LogFactory.getLog(StartupStatus.class);
 
-	private static final String ATTRIBUTE_NAME = "STARTUP_STATUS";
+	protected static final String ATTRIBUTE_NAME = "STARTUP_STATUS";
 
 	// ----------------------------------------------------------------------
 	// static methods

webapp/test/edu/cornell/mannlib/vitro/webapp/i18n/selection/LocaleSelectionSetupTest.java

@@ -0,0 +1,314 @@
+/* $This file is distributed under the terms of the license in /doc/license.txt$ */
+
+package edu.cornell.mannlib.vitro.webapp.i18n.selection;
+
+import static edu.cornell.mannlib.vitro.webapp.i18n.selection.LocaleSelectionSetup.PROPERTY_FORCE_LOCALE;
+import static edu.cornell.mannlib.vitro.webapp.i18n.selection.LocaleSelectionSetup.PROPERTY_SELECTABLE_LOCALES;
+import static edu.cornell.mannlib.vitro.webapp.i18n.selection.SelectedLocale.ATTRIBUTE_NAME;
+import static org.junit.Assert.fail;
+
+import java.util.ArrayList;
+import java.util.Collections;
+import java.util.List;
+import java.util.Locale;
+
+import javax.servlet.ServletContextEvent;
+
+import org.apache.commons.lang.LocaleUtils;
+import org.apache.commons.lang.ObjectUtils;
+import org.apache.log4j.Level;
+import org.junit.After;
+import org.junit.Before;
+import org.junit.Test;
+
+import stubs.edu.cornell.mannlib.vitro.webapp.config.ConfigurationPropertiesStub;
+import stubs.edu.cornell.mannlib.vitro.webapp.startup.StartupStatusStub;
+import stubs.javax.servlet.ServletContextStub;
+import edu.cornell.mannlib.vitro.testing.AbstractTestClass;
+import edu.cornell.mannlib.vitro.webapp.config.ConfigurationProperties;
+import edu.cornell.mannlib.vitro.webapp.i18n.selection.SelectedLocale.ContextSelectedLocale;
+
+/**
+ * TODO
+ */
+public class LocaleSelectionSetupTest extends AbstractTestClass {
+	// ----------------------------------------------------------------------
+	// Infrastructure
+	// ----------------------------------------------------------------------
+
+	private LocaleSelectionSetup lss;
+	private ServletContextStub ctx;
+	private ServletContextEvent sce;
+	private ConfigurationPropertiesStub props;
+	private StartupStatusStub ss;
+
+	private int[] expectedMessageCounts;
+	private Locale expectedForcedLocale;
+	private List<Locale> expectedSelectableLocales;
+
+	@Before
+	public void setup() {
+//		setLoggerLevel(LocaleSelectionSetup.class, Level.DEBUG);
+//		setLoggerLevel(StartupStatusStub.class, Level.DEBUG);
+		setLoggerLevel(ConfigurationProperties.class, Level.WARN);
+
+		ctx = new ServletContextStub();
+		sce = new ServletContextEvent(ctx);
+
+		props = new ConfigurationPropertiesStub();
+		props.setBean(ctx);
+
+		ss = new StartupStatusStub(ctx);
+
+		lss = new LocaleSelectionSetup();
+	}
+
+	@After
+	public void checkExpectations() {
+		if (expectedMessageCounts == null) {
+			fail("expecteMessages() was not called");
+		}
+
+		String message = compareMessageCount("info", ss.getInfoCount(),
+				expectedMessageCounts[0])
+				+ compareMessageCount("warning", ss.getWarningCount(),
+						expectedMessageCounts[1])
+				+ compareMessageCount("fatal", ss.getFatalCount(),
+						expectedMessageCounts[2])
+				+ checkForced()
+				+ checkSelectable();
+		if (!message.isEmpty()) {
+			fail(message);
+		}
+	}
+
+	private String compareMessageCount(String label, int actual, int expected) {
+		if (expected == actual) {
+			return "";
+		} else {
+			return "expecting " + expected + " " + label
+					+ " messages, but received " + actual + "; ";
+		}
+	}
+
+	private String checkForced() {
+		Locale actual = null;
+		Object o = ctx.getAttribute(ATTRIBUTE_NAME);
+		if (o instanceof ContextSelectedLocale) {
+			actual = ((ContextSelectedLocale) o).getForcedLocale();
+		}
+
+		Locale expected = expectedForcedLocale;
+		if (ObjectUtils.equals(expected, actual)) {
+			return "";
+		} else {
+			return "expected forced locale of " + expectedForcedLocale
+					+ ", but was " + actual + "; ";
+		}
+	}
+
+	private String checkSelectable() {
+		List<Locale> actual = Collections.emptyList();
+		Object o = ctx.getAttribute(ATTRIBUTE_NAME);
+		if (o instanceof ContextSelectedLocale) {
+			actual = ((ContextSelectedLocale) o).getSelectableLocales();
+		}
+
+		List<Locale> expected = expectedSelectableLocales;
+		if (expected == null) {
+			expected = Collections.emptyList();
+		}
+
+		if (ObjectUtils.equals(expected, actual)) {
+			return "";
+		} else {
+			return "expected selectable locales of " + expected + ", but was "
+					+ actual + "; ";
+		}
+	}
+
+	// ----------------------------------------------------------------------
+	// The tests
+	// ----------------------------------------------------------------------
+
+	// General functionality
+
+	@Test
+	public void neitherPropertyIsSpecified() {
+		lss.contextInitialized(sce);
+		expectMessages(1, 0, 0);
+	}
+
+	@Test
+	public void forceSuccessL() {
+		props.setProperty(PROPERTY_FORCE_LOCALE, "es");
+		lss.contextInitialized(sce);
+		expectForced("es");
+		expectMessages(1, 0, 0);
+	}
+	
+	@Test
+	public void forceSuccessL_C() {
+		props.setProperty(PROPERTY_FORCE_LOCALE, "es_ES");
+		lss.contextInitialized(sce);
+		expectForced("es_ES");
+		expectMessages(1, 0, 0);
+	}
+	
+	@Test
+	public void forceSuccessL_C_V() {
+		props.setProperty(PROPERTY_FORCE_LOCALE, "no_NO_NY");
+		lss.contextInitialized(sce);
+		expectForced("no_NO_NY");
+		expectMessages(1, 0, 0);
+	}
+
+	@Test
+	public void oneSelectable() {
+		props.setProperty(PROPERTY_SELECTABLE_LOCALES, "fr_FR");
+		lss.contextInitialized(sce);
+		expectSelectable("fr_FR");
+		expectMessages(1, 0, 0);
+	}
+
+	@Test
+	public void twoSelectables() {
+		props.setProperty(PROPERTY_SELECTABLE_LOCALES, "fr_FR, es_PE");
+		lss.contextInitialized(sce);
+		expectSelectable("fr_FR", "es_PE");
+		expectMessages(1, 0, 0);
+	}
+
+	@Test
+	public void bothPropertiesAreSpecified() {
+		props.setProperty(PROPERTY_FORCE_LOCALE, "es_ES");
+		props.setProperty(PROPERTY_SELECTABLE_LOCALES, "fr_FR");
+		lss.contextInitialized(sce);
+		expectForced("es_ES");
+		expectMessages(1, 1, 0);
+	}
+
+	// Locale string syntax (common to both force and selectable)
+
+	@Test
+	public void langaugeIsEmpty() {
+		props.setProperty(PROPERTY_FORCE_LOCALE, "_ES");
+		lss.contextInitialized(sce);
+		expectMessages(0, 1, 0);
+	}
+
+	@Test
+	public void languageWrongLength() {
+		props.setProperty(PROPERTY_FORCE_LOCALE, "e_ES");
+		lss.contextInitialized(sce);
+		expectMessages(0, 1, 0);
+	}
+
+	@Test
+	public void languageNotAlphabetic() {
+		props.setProperty(PROPERTY_FORCE_LOCALE, "e4_ES");
+		lss.contextInitialized(sce);
+		expectMessages(0, 1, 0);
+	}
+
+	@Test
+	public void languageNotLowerCase() {
+		props.setProperty(PROPERTY_FORCE_LOCALE, "eS_ES");
+		lss.contextInitialized(sce);
+		expectMessages(0, 1, 0);
+	}
+
+	@Test
+	public void countryIsEmpty() {
+		props.setProperty(PROPERTY_FORCE_LOCALE, "es_ _13");
+		lss.contextInitialized(sce);
+		expectMessages(0, 1, 0);
+	}
+
+	@Test
+	public void countryWrongLength() {
+		props.setProperty(PROPERTY_FORCE_LOCALE, "es_ESS");
+		lss.contextInitialized(sce);
+		expectMessages(0, 1, 0);
+	}
+
+	@Test
+	public void countryNotAlphabetic() {
+		props.setProperty(PROPERTY_FORCE_LOCALE, "es_E@");
+		lss.contextInitialized(sce);
+		expectMessages(0, 1, 0);
+	}
+
+	@Test
+	public void countryNotUpperCase() {
+		props.setProperty(PROPERTY_FORCE_LOCALE, "es_es");
+		lss.contextInitialized(sce);
+		expectMessages(0, 1, 0);
+	}
+
+	@Test
+	public void variantIsEmpty() {
+		props.setProperty(PROPERTY_FORCE_LOCALE, "es_ES_");
+		lss.contextInitialized(sce);
+		expectMessages(0, 1, 0);
+	}
+
+	@Test
+	public void funkyVariantIsAcceptable() {
+		props.setProperty(PROPERTY_FORCE_LOCALE, "es_ES_123_aa");
+		lss.contextInitialized(sce);
+		expectForced("es_ES_123_aa");
+		expectMessages(1, 1, 0);
+	}
+
+	@Test
+	public void localeNotRecognizedProducesWarning() {
+		props.setProperty(PROPERTY_FORCE_LOCALE, "es_FR");
+		lss.contextInitialized(sce);
+		expectForced("es_FR");
+		expectMessages(1, 1, 0);
+	}
+
+	// Syntax of selectable property
+
+	@Test
+	public void emptySelectableLocaleProducesWarning() {
+		props.setProperty(PROPERTY_SELECTABLE_LOCALES, "es_ES, , fr_FR");
+		lss.contextInitialized(sce);
+		expectSelectable("es_ES", "fr_FR");
+		expectMessages(1, 1, 0);
+	}
+
+	@Test
+	public void blanksAroundCommasAreIgnored() {
+		props.setProperty(PROPERTY_SELECTABLE_LOCALES, "es_ES,en_US   \t ,      fr_FR");
+		lss.contextInitialized(sce);
+		expectSelectable("es_ES", "en_US", "fr_FR");
+		expectMessages(1, 0, 0);
+	}
+
+	// ----------------------------------------------------------------------
+	// helper methods
+	// ----------------------------------------------------------------------
+
+	private void expectMessages(int infoCount, int warningCount, int fatalCount) {
+		this.expectedMessageCounts = new int[] { infoCount, warningCount,
+				fatalCount };
+	}
+
+	private void expectForced(String localeString) {
+		this.expectedForcedLocale = stringToLocale(localeString);
+	}
+
+	private void expectSelectable(String... strings) {
+		List<Locale> list = new ArrayList<Locale>();
+		for (String string : strings) {
+			list.add(stringToLocale(string));
+		}
+		this.expectedSelectableLocales = list;
+	}
+
+	private Locale stringToLocale(String string) {
+		return LocaleUtils.toLocale(string);
+	}
+}

webapp/test/stubs/edu/cornell/mannlib/vitro/webapp/startup/StartupStatusStub.java

@@ -0,0 +1,140 @@
+/* $This file is distributed under the terms of the license in /doc/license.txt$ */
+
+package stubs.edu.cornell.mannlib.vitro.webapp.startup;
+
+import java.util.List;
+
+import javax.servlet.ServletContext;
+import javax.servlet.ServletContextListener;
+
+import org.apache.commons.logging.Log;
+import org.apache.commons.logging.LogFactory;
+
+import edu.cornell.mannlib.vitro.webapp.startup.StartupStatus;
+
+/**
+ * Keep track of how many messages come in.
+ */
+public class StartupStatusStub extends StartupStatus {
+	private static final Log log = LogFactory.getLog(StartupStatusStub.class);
+
+	// ----------------------------------------------------------------------
+	// Stub infrastructure
+	// ----------------------------------------------------------------------
+
+	private int infoCount = 0;
+	private int warningCount = 0;
+	private int fatalCount = 0;
+
+	public StartupStatusStub(ServletContext ctx) {
+		ctx.setAttribute(ATTRIBUTE_NAME, this);
+	}
+
+	public int getInfoCount() {
+		return infoCount;
+	}
+
+	public int getWarningCount() {
+		return warningCount;
+	}
+
+	public int getFatalCount() {
+		return fatalCount;
+	}
+
+	// ----------------------------------------------------------------------
+	// Stub methods
+	// ----------------------------------------------------------------------
+
+	@Override
+	public void info(ServletContextListener listener, String message) {
+		log.debug("INFO: " + message);
+		infoCount++;
+	}
+
+	@Override
+	public void info(ServletContextListener listener, String message,
+			Throwable cause) {
+		log.debug("INFO: " + message + " " + cause);
+		infoCount++;
+	}
+
+	@Override
+	public void warning(ServletContextListener listener, String message) {
+		log.debug("WARNING: " + message);
+		warningCount++;
+	}
+
+	@Override
+	public void warning(ServletContextListener listener, String message,
+			Throwable cause) {
+		log.debug("WARNING: " + message + " " + cause);
+		warningCount++;
+	}
+
+	@Override
+	public void fatal(ServletContextListener listener, String message) {
+		log.debug("FATAL: " + message);
+		fatalCount++;
+	}
+
+	@Override
+	public void fatal(ServletContextListener listener, String message,
+			Throwable cause) {
+		log.debug("FATAL: " + message + " " + cause);
+		fatalCount++;
+	}
+
+	// ----------------------------------------------------------------------
+	// Un-implemented methods
+	// ----------------------------------------------------------------------
+
+	@Override
+	public void listenerNotExecuted(ServletContextListener listener) {
+		throw new RuntimeException(
+				"StartupStatusStub.listenerNotExecuted() not implemented.");
+	}
+
+	@Override
+	public void listenerExecuted(ServletContextListener listener) {
+		throw new RuntimeException(
+				"StartupStatusStub.listenerExecuted() not implemented.");
+	}
+
+	@Override
+	public boolean allClear() {
+		throw new RuntimeException(
+				"StartupStatusStub.allClear() not implemented.");
+	}
+
+	@Override
+	public boolean isStartupAborted() {
+		throw new RuntimeException(
+				"StartupStatusStub.isStartupAborted() not implemented.");
+	}
+
+	@Override
+	public List<StatusItem> getStatusItems() {
+		throw new RuntimeException(
+				"StartupStatusStub.getStatusItems() not implemented.");
+	}
+
+	@Override
+	public List<StatusItem> getErrorItems() {
+		throw new RuntimeException(
+				"StartupStatusStub.getErrorItems() not implemented.");
+	}
+
+	@Override
+	public List<StatusItem> getWarningItems() {
+		throw new RuntimeException(
+				"StartupStatusStub.getWarningItems() not implemented.");
+	}
+
+	@Override
+	public List<StatusItem> getItemsForListener(ServletContextListener listener) {
+		throw new RuntimeException(
+				"StartupStatusStub.getItemsForListener() not implemented.");
+	}
+
+}

webapp/themes/vitro/templates/identity.ftl

@@ -9,6 +9,7 @@
 
     <nav role="navigation">
         <ul id="header-nav" role="list">
+            <#include "languageSelector.ftl">
             <li role="listitem"><a href="${urls.index}" title="index">Index</a></li>
             <#if user.loggedIn>
                 <#if user.hasSiteAdminAccess>

webapp/web/WEB-INF/resources/startup_listeners.txt

@@ -55,6 +55,9 @@ edu.cornell.mannlib.vitro.webapp.services.shortview.ShortViewServiceSetup
 
 edu.ucsf.vitro.opensocial.OpenSocialSmokeTests
 
+# For multiple language support
+edu.cornell.mannlib.vitro.webapp.i18n.selection.LocaleSelectionSetup
+
 # The Solr index uses a "public" permission, so the PropertyRestrictionPolicyHelper 
 #   and the PermissionRegistry must already be set up.
 edu.cornell.mannlib.vitro.webapp.search.solr.SolrSetup

webapp/web/WEB-INF/web.xml

@@ -78,6 +78,16 @@
     <url-pattern>/*</url-pattern>
   </filter-mapping>
 
+  <filter>
+    <description>Override the Locale in the HttpRequest, if appropriate.</description>
+    <filter-name>Locale selection filter</filter-name>
+    <filter-class>edu.cornell.mannlib.vitro.webapp.i18n.selection.LocaleSelectionFilter</filter-class>
+  </filter>
+  <filter-mapping>
+    <filter-name>Locale selection filter</filter-name>
+    <url-pattern>/*</url-pattern>
+  </filter-mapping>
+
   <filter>
     <filter-name>JSession Strip Filter</filter-name>
     <filter-class>edu.cornell.mannlib.vitro.webapp.filters.JSessionStripFilter</filter-class>
@@ -1338,6 +1348,16 @@
     <url-pattern>/orng/*</url-pattern>
   </servlet-mapping>
 
+  <servlet>
+    <description>Multiple-language support. Allows user to select his preferred langauge</description>
+    <servlet-name>LocaleSelectionController</servlet-name>
+    <servlet-class>edu.cornell.mannlib.vitro.webapp.i18n.selection.LocaleSelectionController</servlet-class>
+  </servlet>
+  <servlet-mapping>
+    <servlet-name>LocaleSelectionController</servlet-name>
+    <url-pattern>/selectLocale</url-pattern>
+  </servlet-mapping>
+
 
   <!-- ==================== tag libraries ============================== -->
   <jsp-config>

webapp/web/templates/freemarker/page/partials/identity.ftl

@@ -8,6 +8,7 @@
 
     <nav role="navigation">
         <ul id="header-nav" role="list">
+            <#include "languageSelector.ftl">
             <#if user.loggedIn>
                 <li role="listitem">${user.loginName}</li>
                 <li role="listitem"><a href="${urls.logout}" title="End your session">Log out</a></li>

webapp/web/templates/freemarker/page/partials/languageSelector.ftl

@@ -0,0 +1,31 @@
+<#-- $This file is distributed under the terms of the license in /doc/license.txt$ -->
+
+<#-- 
+  How can this done with images instead of buttons containing images?
+  Why don't the "alt" values show as tooltips?"
+  What was the right way to do this?
+ -->
+
+<#-- This is included by identity.ftl --> 
+<#if selectLocale??>
+    <li>
+      <form method="get" action="${selectLocale.selectLocaleUrl}" >
+        <#list selectLocale.locales as locale>
+          <button type="submit" name="selection" value="${locale.code}">
+            <img src="${locale.imageUrl}" height="15" align="middle" alt="${locale.label}"/>
+          </button>
+          <#if locale_has_next>|</#if>
+        </#list>
+      </form>
+    </li>
+</#if>
+
+<#-- 
+ * selectLocale
+ * -- selectLocaleUrl
+ * -- locales [list of maps]
+ *    -- [map]
+ *       -- code
+ *       -- label (tooltip relative to the current Locale)
+ *       -- imageUrl
+-->