G11n java client [BUG 754] Performance impact on the very first L3 fetch for a non-supported locale

src/main/java/com/vmware/vipclient/i18n/messages/service/ComponentService.java

@@ -5,10 +5,7 @@
 package com.vmware.vipclient.i18n.messages.service;
 
 import java.util.Iterator;
-import java.util.LinkedList;
 import java.util.Locale;
-import java.util.concurrent.Callable;
-import java.util.concurrent.FutureTask;
 
 import com.vmware.vipclient.i18n.VIPCfg;
 import com.vmware.vipclient.i18n.base.DataSourceEnum;
@@ -113,38 +110,52 @@ public MessageCacheItem getMessages(Iterator<Locale> fallbackLocalesIter) {
     		}
     	} else { // Item is not in cache.
 			ProductService ps = new ProductService(dto);
-			if (!ps.isSupportedLocale(Locale.forLanguageTag(dto.getLocale()))) { // Requested locale is not supported
-				Locale matchedLocale = LocaleUtility.pickupLocaleFromList(new LinkedList<>(ps.getSupportedLocales()), Locale.forLanguageTag(dto.getLocale()));
-				if (ps.isSupportedLocale(matchedLocale)) { // Requested locale matches a supported locale (eg. requested locale "fr_CA matches supported locale "fr")
+			Locale locale = Locale.forLanguageTag(dto.getLocale());
+			if (ps.isSupportedLocale(locale) || VIPCfg.getInstance().isPseudo()) {
+				cacheItem = createCacheItem(); // Fetch for the requested locale from data store, create cacheItem and store in cache
+				if (cacheItem.getCachedData().isEmpty())  // Failed to fetch messages for the requested locale
+					cacheItem = getFallbackLocaleMessages(fallbackLocalesIter);
+			} else { // Requested locale is not supported
+				Locale matchedLocale = LocaleUtility.pickupLocaleFromList(ps.getSupportedLocales(), locale);
+				if (matchedLocale != null) { // Requested locale matches a supported locale (eg. requested locale "fr_CA matches supported locale "fr")
 					MessagesDTO matchedLocaleDTO = new MessagesDTO(dto.getComponent(), matchedLocale.toLanguageTag(), dto.getProductID(), dto.getVersion());
-					return new ComponentService(matchedLocaleDTO).getMessages();
-				}
+					cacheItem = new ComponentService(matchedLocaleDTO).getMessages();
+				} else  // Requested locale is not supported and does not match any supported locales
+					cacheItem = getFallbackLocaleMessages(fallbackLocalesIter);
 			}
-
-			//Create and store cacheItem for the requested locale
-			cacheItem = createCacheItem(fallbackLocalesIter);
     	}
     	return cacheItem;
     }
 
+    /**
+     * Gets the messages in the next fallback locale by passing the next fallback locale DTO to a new instance of ComponentService
+	 * and then invoking {@link #getMessages(Iterator)}.
+	 * @param fallbackLocalesIter The fallback locale queue to use in case of failure. If null, no locale fallback will be applied.
+     */
+    private MessageCacheItem getFallbackLocaleMessages(Iterator<Locale> fallbackLocalesIter) {
+		if (fallbackLocalesIter != null && fallbackLocalesIter.hasNext()) {
+			Locale fallbackLocale = fallbackLocalesIter.next();
+			if (fallbackLocale.toLanguageTag().equals(dto.getLocale())) {
+				return getFallbackLocaleMessages(fallbackLocalesIter);
+			}
+			// Use MessageCacheItem of the next fallback locale.
+			MessagesDTO fallbackLocaleDTO = new MessagesDTO(dto.getComponent(), fallbackLocale.toLanguageTag(), dto.getProductID(), dto.getVersion());
+			return new ComponentService(fallbackLocaleDTO).getMessages(fallbackLocalesIter);
+		}
+		return new MessageCacheItem();
+	}
+
 	/**
 	 * Creates a new MessageCacheItem for the DTO and stores it in cache.
-	 *
-	 * @param fallbackLocalesIter The fallback locale queue to use in case of failure. If null, no locale fallback will be applied.
-	 *
 	 */
-    private MessageCacheItem createCacheItem(Iterator<Locale> fallbackLocalesIter) {
+    private MessageCacheItem createCacheItem() {
 		CacheService cacheService = new CacheService(dto);
 		// Create a new cacheItem object to be stored in cache
 		MessageCacheItem cacheItem = new MessageCacheItem();
 
 		refreshCacheItem(cacheItem, VIPCfg.getInstance().getMsgOriginsQueue().iterator());
 		if (!cacheItem.getCachedData().isEmpty()) {
 			cacheService.addCacheOfComponent(cacheItem);
-		} else if (!dto.getLocale().equals(ConstantsKeys.SOURCE) && fallbackLocalesIter != null && fallbackLocalesIter.hasNext()) {
-			// If failed to fetch message for the requested DTO, use MessageCacheItem of the next fallback locale.
-			MessagesDTO fallbackLocaleDTO = new MessagesDTO(dto.getComponent(), fallbackLocalesIter.next().toLanguageTag(), dto.getProductID(), dto.getVersion());
-			cacheItem = new ComponentService(fallbackLocaleDTO).getMessages(fallbackLocalesIter);
 		}
 
 		return cacheItem;

src/main/java/com/vmware/vipclient/i18n/messages/service/ProductService.java

@@ -84,8 +84,8 @@ public Set<Locale> getSupportedLocales() {
     public Set<String> getSupportedLanguageTags() {
         Iterator<DataSourceEnum> msgSourceQueueIter = VIPCfg.getInstance().getMsgOriginsQueue().iterator();
         Set<String> supportedLangTags = new HashSet<>();
-        while(msgSourceQueueIter.hasNext() && supportedLangTags.isEmpty()) {
-            supportedLangTags = getSupportedLanguageTags(msgSourceQueueIter.next());
+        while(msgSourceQueueIter.hasNext()) {
+            supportedLangTags.addAll(getSupportedLanguageTags(msgSourceQueueIter.next()));
         }
         return supportedLangTags;
     }

src/main/java/com/vmware/vipclient/i18n/util/LocaleUtility.java

@@ -4,12 +4,7 @@
  */
 package com.vmware.vipclient.i18n.util;
 
-import java.util.Arrays;
-import java.util.HashMap;
-import java.util.LinkedList;
-import java.util.List;
-import java.util.Locale;
-import java.util.Map;
+import java.util.*;
 import java.util.stream.Collectors;
 
 public class LocaleUtility {
@@ -135,46 +130,33 @@ public static Locale fmtToMappedLocale(Locale zhLocale) {
         return zhLocale;
     }
 
-    /*
-     * pick up the matched locale from a locale list
+    /**
+     * Iterates over the set of locales to find a locale that best matches the preferredLocale.
+     *
+     * <p> </p>A "best match" is defined to be the locale that has the longest common language tag with the preferredLocale.
+     * For example, the supported locale 'de' will be returned for a non-supported preferredLocale 'de-DE'. </p>
+     *
+     * <p> To meet the custom usage of Chinese language, locale "zh" is not considered as a "match" for any non-supported Chinese locale (zh-*).
+     * That is, even if "zh" locale is supported, <code>null</code> will be returned for Chinese locale 'zh-HK' that is not supported. </p>
+     *
+     * @param locales the set of locales to find the best match from.
+     * @param preferredLocale the locale being matched.
+     * @return the best match, if any; <code>null</code> otherwise.
      */
-    public static Locale pickupLocaleFromList(List<Locale> locales,
-            Locale preferredLocale) {
-        Locale langLocale = null;
-        preferredLocale = fmtToMappedLocale(preferredLocale);
-
-        // Use the first locale from the browser's list of preferred languages
-        // for the matching, so that it can keep the same way of getting locale
-        // with other VMware products, like vSphere Web Client, etc.
-        for (Locale configuredLocale : locales) {
-            // Language is matched
-            configuredLocale = fmtToMappedLocale(configuredLocale);
-            if (configuredLocale.getLanguage().equals(
-                    preferredLocale.getLanguage())) {
-                String configuredScript = configuredLocale.getScript();
-                String preferredScript = preferredLocale.getScript();
-                // Country is matched
-                if (((preferredScript.equalsIgnoreCase("")) && (configuredScript
-                        .equalsIgnoreCase("")))
-                        || ((!preferredScript.equalsIgnoreCase("")) && (preferredScript
-                                .equalsIgnoreCase(configuredScript)))) {
-                    return configuredLocale;
-                }
-                langLocale = langLocale == null ? configuredLocale : langLocale;
+    public static Locale pickupLocaleFromList(Set<Locale> locales,
+                                              Locale preferredLocale) {
+		Locale localeObject = fmtToMappedLocale(preferredLocale);
+		Locale bestMatch = Locale.lookup(Arrays.asList(new Locale.LanguageRange(localeObject.toLanguageTag())),
+				locales);
+
+        // handle Chinese locale matching
+        if (bestMatch != null && bestMatch.getLanguage().equals("zh")) {
+            if (!locales.contains(localeObject)) {
+                return null;
             }
         }
 
-        // With Chinese locale which is not configured/supported in web.xml, it
-        // will return 'en_US' as default to meet the usage custom of Chinese,
-        // e.g. for 'zh-HK' from client(browser) which is not
-        // configured/supported yet, it will return 'en_US';
-        // Other locale, like 'de-DE' 'ja-JP' etc.,
-        // it will return 'de' 'ja'(main/parent language).
-        if (langLocale != null
-                && (!langLocale.getLanguage().equalsIgnoreCase("zh"))) {
-            return new Locale(langLocale.getLanguage());
-        }
-        return preferredLocale;
+        return bestMatch;
     }
 
     /**

src/test/java/com/vmware/vip/i18n/HttpRequesterTest.java

@@ -76,7 +76,7 @@ public void addHeaderParamsTest_() {
         	// Exception is expected
         }
 
-        WireMock.verify(WireMock.getRequestedFor(WireMock.urlMatching(url)).withHeader(key1, WireMock.equalTo(value1))
+        WireMock.verify(WireMock.getRequestedFor(WireMock.urlMatching(url2+"|"+url)).withHeader(key1, WireMock.equalTo(value1))
                 .withHeader(key2, WireMock.equalTo(value2)));
     }
 
@@ -104,7 +104,7 @@ public void addHeaderParamsTest() {
                 .getMessageInstance(TranslationMessage.class);
         tm.getString2("default", "messages", new Locale("zh", "Hans"), "table.host");
 
-        WireMock.verify(WireMock.getRequestedFor(WireMock.urlMatching(url)).withHeader(key1, WireMock.equalTo(value1))
+        WireMock.verify(WireMock.getRequestedFor(WireMock.urlMatching(url2+"|"+url)).withHeader(key1, WireMock.equalTo(value1))
                 .withHeader(key2, WireMock.equalTo(value2)));
     }
 

src/test/java/com/vmware/vip/i18n/LocaleTest.java

@@ -15,11 +15,7 @@
 import org.junit.Before;
 import org.junit.Test;
 
-import java.util.ArrayList;
-import java.util.Arrays;
-import java.util.List;
-import java.util.Locale;
-import java.util.Map;
+import java.util.*;
 import java.util.concurrent.locks.Condition;
 import java.util.concurrent.locks.Lock;
 import java.util.concurrent.locks.ReentrantLock;
@@ -46,34 +42,72 @@ public void init() {
     public void testPickupLocaleFromList() {
         Locale[] supportedLocales = { Locale.forLanguageTag("de"),
                 Locale.forLanguageTag("es"), Locale.forLanguageTag("fr"),
+                Locale.forLanguageTag("fr-CA"),
                 Locale.forLanguageTag("ja"), Locale.forLanguageTag("ko"),
+                Locale.forLanguageTag("zh"),
                 Locale.forLanguageTag("zh-Hans"),
                 Locale.forLanguageTag("zh-Hant")
 
         };
         Locale[] testLocales = { Locale.forLanguageTag("de"),
                 Locale.forLanguageTag("es"), Locale.forLanguageTag("fr"),
+                Locale.forLanguageTag("fr-CA"), Locale.forLanguageTag("fr-FR"),
                 Locale.forLanguageTag("ja"), Locale.forLanguageTag("ko"),
-                Locale.forLanguageTag("zh"), Locale.forLanguageTag("zh-CN"),
+                Locale.forLanguageTag("zh"),
+                Locale.forLanguageTag("zh-CN"),
                 Locale.forLanguageTag("zh-TW"),
                 Locale.forLanguageTag("zh-HANS-CN"),
                 Locale.forLanguageTag("zh-HANT-TW"),
                 Locale.forLanguageTag("zh-HANS"),
                 Locale.forLanguageTag("zh-HANT") };
 
-        String[] expectedLocales = { "de", "es", "fr", "ja", "ko", "zh",
+        String[] expectedLocales = { "de", "es", "fr", "fr-CA", "fr", "ja", "ko", "zh",
                 "zh-Hans", "zh-Hant", "zh-Hans", "zh-Hant", "zh-Hans", "zh-Hant" };
 
         for (int i = 0; i < testLocales.length; i++) {
             String matchedLanguageTag = LocaleUtility.pickupLocaleFromList(
-                    Arrays.asList(supportedLocales), testLocales[i])
+                    new HashSet<>(Arrays.asList(supportedLocales)), testLocales[i])
                     .toLanguageTag();
 
             logger.debug(matchedLanguageTag + "-----" + expectedLocales[i]);
             Assert.assertEquals(expectedLocales[i], matchedLanguageTag);
         }
     }
 
+    @Test
+    public void testPickupLocaleFromListNotFound() {
+        Locale[] supportedLocales = { Locale.forLanguageTag("de"),
+                Locale.forLanguageTag("es"), Locale.forLanguageTag("fr"),
+                Locale.forLanguageTag("fr-CA"),
+                Locale.forLanguageTag("ja"), Locale.forLanguageTag("ko"),
+                Locale.forLanguageTag("zh-Hans"),
+                Locale.forLanguageTag("zh-Hant")
+
+        };
+        Assert.assertNull(LocaleUtility.pickupLocaleFromList(new HashSet<>(Arrays.asList(supportedLocales)), Locale.forLanguageTag("fil")));
+    }
+
+    /**
+     *  For any Chinese locale (zh-*) that is not supported,
+     *  return null so that fallback locale will be used even if "zh" is supported.
+     *  For any non-Chinese locale, return the best match (e.g. 'de' if 'de-DE' is not supported).
+     */
+    @Test
+    public void testPickupLocaleFromListZh() {
+        Locale[] supportedLocales = {
+                Locale.forLanguageTag("zh"),
+                Locale.forLanguageTag("zh-Hans")
+
+        };
+        Assert.assertNull(LocaleUtility.pickupLocaleFromList(new HashSet<>(Arrays.asList(supportedLocales)), Locale.forLanguageTag("zh-HK")));
+        Assert.assertEquals("zh", LocaleUtility.pickupLocaleFromList(new HashSet<>(Arrays.asList(supportedLocales)),
+                Locale.forLanguageTag("zh")).toLanguageTag());
+        Assert.assertEquals("zh-Hans", LocaleUtility.pickupLocaleFromList(new HashSet<>(Arrays.asList(supportedLocales)),
+                Locale.forLanguageTag("zh-CN")).toLanguageTag());
+        Assert.assertNull(LocaleUtility.pickupLocaleFromList(new HashSet<>(Arrays.asList(supportedLocales)),
+                Locale.forLanguageTag("zh-TW")));
+    }
+
     @Test
     public void normalizeToLanguageTag() {
         String[] testLocaleStrs = { "de", "es", "fr", "ja", "ko", "en-US", "zh-CN", "zh-TW",