feat: introduce i18n support for side nav flow counterpart (#5208)

Author: ugur-vaadin

vaadin-side-nav-flow-parent/vaadin-side-nav-flow-integration-tests/src/main/java/com/vaadin/flow/component/sidenav/tests/SideNavI18NPage.java

@@ -0,0 +1,38 @@
+/*
+ * Copyright 2023 Vaadin Ltd.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License"); you may not
+ * use this file except in compliance with the License. You may obtain a copy of
+ * the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
+ * WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
+ * License for the specific language governing permissions and limitations under
+ * the License.
+ */
+package com.vaadin.flow.component.sidenav.tests;
+
+import com.vaadin.flow.component.html.Div;
+import com.vaadin.flow.component.html.NativeButton;
+import com.vaadin.flow.component.sidenav.SideNav;
+import com.vaadin.flow.component.sidenav.SideNavItem;
+import com.vaadin.flow.router.Route;
+
+@Route("vaadin-side-nav/side-nav-i18n")
+public class SideNavI18NPage extends Div {
+
+    public SideNavI18NPage() {
+        SideNav sideNav = new SideNav();
+        sideNav.addItem(new SideNavItem("Item 1"));
+        sideNav.addItem(new SideNavItem("Item 2"));
+
+        NativeButton setI18n = new NativeButton("Set i18n", e -> sideNav
+                .setI18n(new SideNav.SideNavI18n().setToggle("Updated")));
+        setI18n.setId("set-i18n");
+
+        add(sideNav, setI18n);
+    }
+}

vaadin-side-nav-flow-parent/vaadin-side-nav-flow-integration-tests/src/test/java/com/vaadin/flow/component/sidenav/tests/SideNavI18NIT.java

@@ -0,0 +1,62 @@
+/*
+ * Copyright 2023 Vaadin Ltd.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License"); you may not
+ * use this file except in compliance with the License. You may obtain a copy of
+ * the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
+ * WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
+ * License for the specific language governing permissions and limitations under
+ * the License.
+ */
+
+package com.vaadin.flow.component.sidenav.tests;
+
+import com.vaadin.flow.component.sidenav.testbench.SideNavItemElement;
+import com.vaadin.flow.testutil.TestPath;
+import com.vaadin.tests.AbstractComponentIT;
+import org.junit.Assert;
+import org.junit.Before;
+import org.junit.Test;
+import org.openqa.selenium.By;
+
+import java.util.List;
+
+/**
+ * Integration tests for the {@link SideNavI18NPage}.
+ *
+ * @author Vaadin Ltd.
+ */
+@TestPath("vaadin-side-nav/side-nav-i18n")
+public class SideNavI18NIT extends AbstractComponentIT {
+
+    @Before
+    public void init() {
+        open();
+    }
+
+    @Test
+    public void itemsHaveCorrectDefaultI18N() {
+        List<SideNavItemElement> elements = $(SideNavItemElement.class).all();
+        elements.forEach(element -> Assert.assertEquals("Toggle child items",
+                getI18nText(element)));
+    }
+
+    @Test
+    public void setI18n_i18nIsUpdated() {
+        $("button").id("set-i18n").click();
+
+        List<SideNavItemElement> elements = $(SideNavItemElement.class).all();
+        elements.forEach(element -> Assert.assertEquals("Updated",
+                getI18nText(element)));
+    }
+
+    private String getI18nText(SideNavItemElement element) {
+        return element.getWrappedElement().getShadowRoot()
+                .findElement(By.id("i18n")).getText();
+    }
+}

vaadin-side-nav-flow-parent/vaadin-side-nav-flow/src/main/java/com/vaadin/flow/component/sidenav/SideNav.java

@@ -25,6 +25,10 @@
 import com.vaadin.flow.component.dependency.JsModule;
 import com.vaadin.flow.component.dependency.NpmPackage;
 import com.vaadin.flow.dom.Element;
+import com.vaadin.flow.internal.JsonSerializer;
+
+import java.io.Serializable;
+import java.util.Objects;
 
 /**
  * A side navigation menu with support for hierarchical and flat menus.
@@ -42,6 +46,8 @@ public class SideNav extends SideNavItemContainer implements HasSize, HasStyle {
 
     private Element labelElement;
 
+    private SideNavI18n i18n;
+
     /**
      * Creates a new menu without any label.
      */
@@ -151,6 +157,35 @@ protected void onAttach(AttachEvent attachEvent) {
         checkFeatureFlag();
     }
 
+    /**
+     * Gets the internationalization object previously set for this component.
+     * <p>
+     * Note: updating the object content that is gotten from this method will
+     * not update the lang on the component if not set back using
+     * {@link SideNav#setI18n(SideNavI18n)}
+     *
+     * @return the i18n object. It will be <code>null</code>, If the i18n
+     *         properties weren't set.
+     */
+    public SideNavI18n getI18n() {
+        return i18n;
+    }
+
+    /**
+     * Updates the i18n settings in the web component. Merges the
+     * {@link SideNavI18n} settings with the current / default settings of the
+     * web component.
+     *
+     * @param i18n
+     *            the internationalized properties, not <code>null</code>
+     */
+    public void setI18n(SideNavI18n i18n) {
+        Objects.requireNonNull(i18n,
+                "The i18N properties object should not be null");
+        this.i18n = i18n;
+        getElement().setPropertyJson("i18n", JsonSerializer.toJson(i18n));
+    }
+
     /**
      * Checks whether the SideNav component feature flag is active. Succeeds if
      * the flag is enabled, and throws otherwise.
@@ -180,4 +215,33 @@ protected FeatureFlags getFeatureFlags() {
                 .get(UI.getCurrent().getSession().getService().getContext());
     }
 
+    /**
+     * The internationalization properties for {@link SideNav}.
+     */
+    public static class SideNavI18n implements Serializable {
+        private String toggle;
+
+        /**
+         * The text announced by screen readers when focusing the button for
+         * toggling child items.
+         *
+         * @return the translated expression for toggling child items
+         */
+        public String getToggle() {
+            return toggle;
+        }
+
+        /**
+         * Sets the text announced by screen readers when focusing the button
+         * for toggling child items.
+         *
+         * @param toggle
+         *            the translated expression for toggling child items
+         * @return this instance for method chaining
+         */
+        public SideNavI18n setToggle(String toggle) {
+            this.toggle = toggle;
+            return this;
+        }
+    }
 }