Locale Lookup

Trying to find a best-match for a given locale. Otherwise, returning a
fallback but never returning an unsupported locale.

src/main/java/de/mstock/monolith/config/I18nConfig.java

@@ -10,11 +10,13 @@ import org.springframework.web.servlet.LocaleResolver;
 import org.springframework.web.servlet.config.annotation.WebMvcConfigurerAdapter;
 import org.springframework.web.servlet.i18n.AcceptHeaderLocaleResolver;
 
+import de.mstock.monolith.web.i18n.AcceptHeaderLookupLocaleResolver;
+
 @Configuration
 public class I18nConfig extends WebMvcConfigurerAdapter {
 
   private static final List<Locale> SUPPORTED_LOCALES =
-      Arrays.asList(new Locale("de_DE"), new Locale("en_US"));
+      Arrays.asList(new Locale("en", "US"), new Locale("de", "DE"));
 
   /**
    * Creates a Bean, managed by Spring.
@@ -23,9 +25,10 @@ public class I18nConfig extends WebMvcConfigurerAdapter {
    */
   @Bean
   public LocaleResolver localeResolver() {
-    AcceptHeaderLocaleResolver localeResolver = new AcceptHeaderLocaleResolver();
+    Locale defaultLocale = SUPPORTED_LOCALES.get(0);
+    AcceptHeaderLocaleResolver localeResolver = new AcceptHeaderLookupLocaleResolver(defaultLocale);
     localeResolver.setSupportedLocales(SUPPORTED_LOCALES);
-    localeResolver.setDefaultLocale(Locale.US);
+    localeResolver.setDefaultLocale(defaultLocale);
     return localeResolver;
   }
 

src/main/java/de/mstock/monolith/web/i18n/AcceptHeaderLookupLocaleResolver.java

@@ -0,0 +1,44 @@
+package de.mstock.monolith.web.i18n;
+
+import java.util.ArrayList;
+import java.util.Arrays;
+import java.util.List;
+import java.util.Locale;
+import java.util.Locale.LanguageRange;
+
+import javax.servlet.http.HttpServletRequest;
+
+import org.springframework.web.servlet.i18n.AcceptHeaderLocaleResolver;
+
+public class AcceptHeaderLookupLocaleResolver extends AcceptHeaderLocaleResolver {
+
+  private final Locale fallback;
+  private final ArrayList<LanguageRange> ranges = new ArrayList<>();
+
+  public AcceptHeaderLookupLocaleResolver(Locale fallback) {
+    this.fallback = fallback;
+  }
+
+  @Override
+  public void setSupportedLocales(List<Locale> locales) {
+    super.setSupportedLocales(locales);
+    ranges.clear();
+    for (Locale supportedLocale : getSupportedLocales()) {
+      ranges.add(new LanguageRange(supportedLocale.getLanguage() + "-*"));
+    }
+  }
+
+  @Override
+  public Locale resolveLocale(HttpServletRequest request) {
+    Locale resolvedLocale = super.resolveLocale(request);
+    if (getSupportedLocales().contains(resolvedLocale)) {
+      return resolvedLocale;
+    }
+    Locale lookup = Locale.lookup(ranges, Arrays.asList(resolvedLocale));
+    if (lookup != null) {
+      return lookup;
+    }
+    return fallback;
+  }
+
+}

src/main/resources/messages.properties

@@ -1,18 +1 @@
 company = Mosh
-general.backToTop = Back to top
-general.sampleImage = Sample image
-navigation.toggle = Toggle navigation
-navigation.legalNotice = Legal Notice
-products.kiwis=Kiwis
-products.blueberries=Blueberries
-products.cherries=Cherries
-products.kiwis.prettyUrlFragment=kiwis
-products.blueberries.prettyUrlFragment=blueberries
-products.cherries.prettyUrlFragment=cherries
-products.goto = Go to product
-features.headline1 = Delicious Fruits.
-features.subheadline1 = It'll blow your mind.
-features.headline2 = Oh yeah, it's that good.
-features.subheadline2 = See for yourself.
-features.headline3 = And lastly, this one.
-features.subheadline3 = Checkmate.

src/main/resources/messages_en.properties

@@ -0,0 +1,17 @@
+general.backToTop = Back to top
+general.sampleImage = Sample image
+navigation.toggle = Toggle navigation
+navigation.legalNotice = Legal Notice
+products.kiwis=Kiwis
+products.blueberries=Blueberries
+products.cherries=Cherries
+products.kiwis.prettyUrlFragment=kiwis
+products.blueberries.prettyUrlFragment=blueberries
+products.cherries.prettyUrlFragment=cherries
+products.goto = Go to product
+features.headline1 = Delicious Fruits.
+features.subheadline1 = It'll blow your mind.
+features.headline2 = Oh yeah, it's that good.
+features.subheadline2 = See for yourself.
+features.headline3 = And lastly, this one.
+features.subheadline3 = Checkmate.

src/test/java/de/mstock/monolith/MonolithApplicationTests.java

@@ -1,19 +0,0 @@
-package de.mstock.monolith;
-
-import static org.junit.Assert.assertTrue;
-
-import org.junit.Test;
-import org.junit.runner.RunWith;
-import org.springframework.boot.test.context.SpringBootTest;
-import org.springframework.test.context.junit4.SpringRunner;
-
-@RunWith(SpringRunner.class)
-@SpringBootTest
-public class MonolithApplicationTests {
-
-  @Test
-  public void contextLoads() {
-    assertTrue(true);
-  }
-
-}

src/test/java/de/mstock/monolith/web/HomepageControllerTest.java

@@ -0,0 +1,80 @@
+package de.mstock.monolith.web;
+
+import static org.hamcrest.CoreMatchers.containsString;
+import static org.springframework.test.web.servlet.request.MockMvcRequestBuilders.get;
+import static org.springframework.test.web.servlet.result.MockMvcResultMatchers.content;
+import static org.springframework.test.web.servlet.result.MockMvcResultMatchers.status;
+
+import java.util.Locale;
+
+import org.junit.Before;
+import org.junit.Test;
+import org.junit.runner.RunWith;
+import org.springframework.beans.factory.annotation.Autowired;
+import org.springframework.boot.test.context.SpringBootTest;
+import org.springframework.http.HttpHeaders;
+import org.springframework.test.context.junit4.SpringRunner;
+import org.springframework.test.context.web.WebAppConfiguration;
+import org.springframework.test.web.servlet.MockMvc;
+import org.springframework.test.web.servlet.setup.MockMvcBuilders;
+import org.springframework.web.context.WebApplicationContext;
+
+@RunWith(SpringRunner.class)
+@SpringBootTest
+@WebAppConfiguration
+public class HomepageControllerTest {
+
+  @Autowired
+  private WebApplicationContext webApplicationContext;
+
+  private MockMvc mockMvc;
+
+  @Before
+  public void setup() {
+    mockMvc = MockMvcBuilders.webAppContextSetup(webApplicationContext).build();
+  }
+
+  @Test
+  public void shouldPrintEnglishTexts() throws Exception {
+    mockMvc.perform(get("/").header(HttpHeaders.ACCEPT_LANGUAGE, "en").locale(new Locale("en")))
+        .andExpect(status().isOk()).andExpect(content().string(containsString("Fruits")))
+        .andExpect(content().string(containsString("to top")));
+  }
+
+  @Test
+  public void shouldPrintGermanTexts() throws Exception {
+    mockMvc.perform(get("/").header(HttpHeaders.ACCEPT_LANGUAGE, "de").locale(new Locale("de")))
+        .andExpect(status().isOk()).andExpect(status().isOk())
+        .andExpect(content().string(containsString("Obst")))
+        .andExpect(content().string(containsString("nach oben")));
+  }
+
+  @Test
+  public void shouldPrintEnglishTextsForAustralia() throws Exception {
+    mockMvc
+        .perform(
+            get("/").header(HttpHeaders.ACCEPT_LANGUAGE, "en-AU").locale(new Locale("en", "AU")))
+        .andExpect(status().isOk()).andExpect(content().string(containsString("Fruits")))
+        .andExpect(content().string(containsString("to top")));
+  }
+
+  @Test
+  public void shouldPrintGermanTextsForAustria() throws Exception {
+    mockMvc
+        .perform(
+            get("/").header(HttpHeaders.ACCEPT_LANGUAGE, "de-AT").locale(new Locale("de", "AT")))
+        .andExpect(status().isOk()).andExpect(status().isOk())
+        .andExpect(content().string(containsString("Obst")))
+        .andExpect(content().string(containsString("nach oben")));
+  }
+
+  @Test
+  public void shouldPrintEnglishTextsForChina() throws Exception {
+    mockMvc
+        .perform(
+            get("/").header(HttpHeaders.ACCEPT_LANGUAGE, "zh-CN").locale(new Locale("zh", "CN")))
+        .andExpect(status().isOk()).andExpect(content().string(containsString("Fruits")))
+        .andExpect(content().string(containsString("to top")));
+  }
+
+}