Resolve "Préciser la locale dans les appels REST"

Closes #16 (closed)

www-client/src/main/java/fr/agrometinfo/www/client/App.java

 package fr.agrometinfo.www.client;
 
+import org.dominokit.domino.api.shared.extension.ContextAggregator;
 import org.dominokit.rest.DominoRestConfig;
+import org.dominokit.rest.shared.request.RequestInterceptor;
+import org.dominokit.rest.shared.request.ServerRequest;
 import org.gwtproject.event.shared.Event;
 import org.gwtproject.event.shared.EventBus;
 import org.gwtproject.event.shared.SimpleEventBus;
+import org.gwtproject.i18n.shared.cldr.LocaleInfo;
 import org.pepstock.charba.client.Charba;
 
 import com.google.gwt.core.client.EntryPoint;
@@ -20,6 +24,22 @@ import fr.agrometinfo.www.client.presenter.LoginPresenter;
  * @author Olivier Maury
  */
 public class App implements EntryPoint {
+    /**
+     * Global interceptors allows us to intercept the requests of domino-rest and
+     * modify the requests before they are sent to the server.
+     *
+     * Add the locale from the interface to make sure server response match the
+     * interface.
+     */
+    class LocaleInterceptor implements RequestInterceptor {
+        @Override
+        public void interceptRequest(final ServerRequest request,
+                final ContextAggregator.ContextWait<ServerRequest> contextWait) {
+            request.setHeader("Accept-Language", LocaleInfo.getCurrentLocale().getLocaleName());
+            contextWait.complete(request);
+        }
+    }
+
     /**
      * Dispatches {@link Event}s to interested parties.
      */
@@ -45,6 +65,7 @@ public class App implements EntryPoint {
         GWT.log("onModuleLoad()");
 
         DominoRestConfig.initDefaults();
+        DominoRestConfig.getInstance().addRequestInterceptor(new LocaleInterceptor());
         DominoRestConfig.getInstance().setDefaultResourceRootPath(Window.Location.getPath() + "/rs");
 
         // enabling Charba