Introduce TemplateInstance.setVariant

Dairdevil · Apr 15, 2024 · f0c5435 · f0c5435
1 parent 9f66268
commit f0c5435
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Showing 3 changed files with 31 additions and 3 deletions.
diff --git a/docs/src/main/asciidoc/qute-reference.adoc b/docs/src/main/asciidoc/qute-reference.adoc
@@ -1659,7 +1659,7 @@ public class CustomLocator implements TemplateLocator {
 === Template Variants
 
 Sometimes it's useful to render a specific variant of the template based on the content negotiation.
-This can be done by setting a special attribute via `TemplateInstance.setAttribute()`:
+This can be done by setting a special attribute via `TemplateInstance.setVariant()`:
 
 [source,java]
 ----
@@ -1672,7 +1672,9 @@ class MyService {
     ItemManager manager;
 
     String renderItems() {
-       return items.data("items",manager.findItems()).setAttribute(TemplateInstance.SELECTED_VARIANT, new Variant(Locale.getDefault(),"text/html","UTF-8")).render();
+       return items.data("items", manager.findItems())
+                   .setVariant(new Variant(Locale.getDefault(), "text/html", "UTF-8"))
+                   .render();
     }
 }
 ----

diff --git a/independent-projects/qute/core/src/main/java/io/quarkus/qute/TemplateInstance.java b/independent-projects/qute/core/src/main/java/io/quarkus/qute/TemplateInstance.java
@@ -201,6 +201,16 @@ default TemplateInstance setLocale(Locale locale) {
         return setAttribute(LOCALE, locale);
     }
 
+    /**
+     * Sets the variant attribute that can be used to select a specific variant of the template.
+     *
+     * @param variant the variant
+     * @return self
+     */
+    default TemplateInstance setVariant(Variant variant) {
+        return setAttribute(SELECTED_VARIANT, variant);
+    }
+
     /**
      * This component can be used to initialize a template instance, i.e. the data and attributes.
      *

diff --git a/independent-projects/qute/core/src/test/java/io/quarkus/qute/TemplateInstanceTest.java b/independent-projects/qute/core/src/test/java/io/quarkus/qute/TemplateInstanceTest.java
@@ -4,7 +4,6 @@
 import static org.junit.jupiter.api.Assertions.assertFalse;
 import static org.junit.jupiter.api.Assertions.assertTrue;
 
-import java.util.List;
 import java.util.Locale;
 import java.util.concurrent.atomic.AtomicBoolean;
 
@@ -78,4 +77,21 @@ public void testLocale() throws Exception {
         Template hello = engine.parse("Hello {locale}!");
         assertEquals("Hello fr!", hello.instance().setLocale(Locale.FRENCH).render());
     }
+
+    @Test
+    public void testVariant() {
+        Engine engine = Engine.builder().addDefaults()
+                .addValueResolver(ValueResolver.builder()
+                        .applyToName("variant")
+                        .resolveSync(ctx -> ctx.getAttribute(TemplateInstance.SELECTED_VARIANT))
+                        .build())
+                .addValueResolver(ValueResolver.builder()
+                        .appliesTo(ctx -> ctx.getBase() instanceof Variant && ctx.getName().equals("contentType"))
+                        .resolveSync(ctx -> ((Variant) ctx.getBase()).getContentType())
+                        .build())
+                .build();
+        Template hello = engine.parse("Hello {variant.contentType}!");
+        String render = hello.instance().setVariant(Variant.forContentType(Variant.TEXT_HTML)).render();
+        assertEquals("Hello text/html!", render);
+    }
 }