Use @Inherited for annotations that have inherited semantic (#12351).

Change-Id: I70f0d79095bfd05b83905df6a3eedd1a5e93b48e

9 files changed, 152 insertions, 9 deletions

diff --git a/WebContent/release-notes.html b/WebContent/release-notes.html
index 4286b3ace0..f7b5611be5 100644
--- a/WebContent/release-notes.html
+++ b/WebContent/release-notes.html
@@ -140,6 +140,8 @@
                 cause problems with external libraries compiled against said versions.</li>
             <li>Declarative format is now using "vaadin-" as a default prefix instead of the "v-" prefix used in 7.5. 
                 This default can be changed in deployment configuration.</li>
+            <li>The annotations @PreserveOnRefresh, @Push, @Theme, @Title, @VaadinServletConfiguration and @Widgetset now use
+                @Inherited. The annotation is also looked up in extended interfaces for backwards compatibility.</li>
         </ul>
         <h3 id="knownissues">Known Issues and Limitations</h3>
         <ul>
diff --git a/server/src/com/vaadin/annotations/PreserveOnRefresh.java b/server/src/com/vaadin/annotations/PreserveOnRefresh.java
index 7f4ef3ffe5..86723b97fc 100644
--- a/server/src/com/vaadin/annotations/PreserveOnRefresh.java
+++ b/server/src/com/vaadin/annotations/PreserveOnRefresh.java
@@ -17,6 +17,7 @@
 package com.vaadin.annotations;
 
 import java.lang.annotation.ElementType;
+import java.lang.annotation.Inherited;
 import java.lang.annotation.Retention;
 import java.lang.annotation.RetentionPolicy;
 import java.lang.annotation.Target;
@@ -45,6 +46,7 @@ import com.vaadin.ui.UI;
  */
 @Target(ElementType.TYPE)
 @Retention(RetentionPolicy.RUNTIME)
+@Inherited
 public @interface PreserveOnRefresh {
     // Empty marker annotation
 }
diff --git a/server/src/com/vaadin/annotations/Push.java b/server/src/com/vaadin/annotations/Push.java
index b6a28c1560..736bc4488b 100644
--- a/server/src/com/vaadin/annotations/Push.java
+++ b/server/src/com/vaadin/annotations/Push.java
@@ -17,6 +17,7 @@
 package com.vaadin.annotations;
 
 import java.lang.annotation.ElementType;
+import java.lang.annotation.Inherited;
 import java.lang.annotation.Retention;
 import java.lang.annotation.RetentionPolicy;
 import java.lang.annotation.Target;
@@ -38,6 +39,7 @@ import com.vaadin.ui.UI;
  */
 @Retention(RetentionPolicy.RUNTIME)
 @Target(ElementType.TYPE)
+@Inherited
 public @interface Push {
     /**
      * Returns the {@link PushMode} to use for the annotated UI. The default
diff --git a/server/src/com/vaadin/annotations/Theme.java b/server/src/com/vaadin/annotations/Theme.java
index 61c47389ad..03fa1179bc 100644
--- a/server/src/com/vaadin/annotations/Theme.java
+++ b/server/src/com/vaadin/annotations/Theme.java
@@ -17,6 +17,7 @@
 package com.vaadin.annotations;
 
 import java.lang.annotation.ElementType;
+import java.lang.annotation.Inherited;
 import java.lang.annotation.Retention;
 import java.lang.annotation.RetentionPolicy;
 import java.lang.annotation.Target;
@@ -28,6 +29,7 @@ import com.vaadin.ui.UI;
  */
 @Retention(RetentionPolicy.RUNTIME)
 @Target(ElementType.TYPE)
+@Inherited
 public @interface Theme {
     /**
      * @return simple name of the theme
diff --git a/server/src/com/vaadin/annotations/Title.java b/server/src/com/vaadin/annotations/Title.java
index 38a3d75f17..07eaf17e33 100644
--- a/server/src/com/vaadin/annotations/Title.java
+++ b/server/src/com/vaadin/annotations/Title.java
@@ -17,6 +17,7 @@
 package com.vaadin.annotations;
 
 import java.lang.annotation.ElementType;
+import java.lang.annotation.Inherited;
 import java.lang.annotation.Retention;
 import java.lang.annotation.RetentionPolicy;
 import java.lang.annotation.Target;
@@ -28,6 +29,7 @@ import com.vaadin.ui.UI;
  */
 @Retention(RetentionPolicy.RUNTIME)
 @Target(ElementType.TYPE)
+@Inherited
 public @interface Title {
     /**
      * Gets the HTML title that should be used if the UI is used on it's own.
diff --git a/server/src/com/vaadin/annotations/VaadinServletConfiguration.java b/server/src/com/vaadin/annotations/VaadinServletConfiguration.java
index 00af38ecc1..907f2c3a0c 100644
--- a/server/src/com/vaadin/annotations/VaadinServletConfiguration.java
+++ b/server/src/com/vaadin/annotations/VaadinServletConfiguration.java
@@ -18,6 +18,7 @@ package com.vaadin.annotations;
 
 import java.lang.annotation.Documented;
 import java.lang.annotation.ElementType;
+import java.lang.annotation.Inherited;
 import java.lang.annotation.Retention;
 import java.lang.annotation.RetentionPolicy;
 import java.lang.annotation.Target;
@@ -44,6 +45,7 @@ import com.vaadin.ui.UI;
  */
 @Retention(RetentionPolicy.RUNTIME)
 @Target(ElementType.TYPE)
+@Inherited
 public @interface VaadinServletConfiguration {
     /**
      * Defines the init parameter name for methods in
diff --git a/server/src/com/vaadin/annotations/Widgetset.java b/server/src/com/vaadin/annotations/Widgetset.java
index c6ef6a7194..2dcf93af13 100644
--- a/server/src/com/vaadin/annotations/Widgetset.java
+++ b/server/src/com/vaadin/annotations/Widgetset.java
@@ -17,6 +17,7 @@
 package com.vaadin.annotations;
 
 import java.lang.annotation.ElementType;
+import java.lang.annotation.Inherited;
 import java.lang.annotation.Retention;
 import java.lang.annotation.RetentionPolicy;
 import java.lang.annotation.Target;
@@ -28,6 +29,7 @@ import com.vaadin.ui.UI;
  */
 @Retention(RetentionPolicy.RUNTIME)
 @Target(ElementType.TYPE)
+@Inherited
 public @interface Widgetset {
     /**
      * @return name of the widgetset
diff --git a/server/src/com/vaadin/server/UIProvider.java b/server/src/com/vaadin/server/UIProvider.java
index d3d834cad7..4ed86b9c31 100644
--- a/server/src/com/vaadin/server/UIProvider.java
+++ b/server/src/com/vaadin/server/UIProvider.java
@@ -18,6 +18,7 @@ package com.vaadin.server;
 
 import java.io.Serializable;
 import java.lang.annotation.Annotation;
+import java.lang.annotation.Inherited;
 
 import com.vaadin.annotations.PreserveOnRefresh;
 import com.vaadin.annotations.Push;
@@ -43,8 +44,15 @@ public abstract class UIProvider implements Serializable {
 
     /**
      * Helper to get an annotation for a class. If the annotation is not present
-     * on the target class, its super classes and implemented interfaces are
-     * also searched for the annotation.
+     * on the target class, its super classes and directly implemented
+     * interfaces are also searched for the annotation. Interfaces implemented
+     * by superclasses are not taken into account.
+     * <p>
+     * Note that searching implemented interfaces for {@code @Inherited}
+     * annotations and searching for superclasses for non-inherited annotations
+     * do not follow the standard semantics and are supported for backwards
+     * compatibility. Future versions of the framework might only support the
+     * standard semantics of {@code @Inherited}.
      * 
      * @param clazz
      *            the class from which the annotation should be found
@@ -55,18 +63,26 @@ public abstract class UIProvider implements Serializable {
      */
     protected static <T extends Annotation> T getAnnotationFor(Class<?> clazz,
             Class<T> annotationType) {
-        // Find from the class hierarchy
-        Class<?> currentType = clazz;
-        while (currentType != Object.class) {
-            T annotation = currentType.getAnnotation(annotationType);
+        // Don't discover hierarchy if annotation is inherited
+        if (annotationType.getAnnotation(Inherited.class) != null) {
+            T annotation = clazz.getAnnotation(annotationType);
             if (annotation != null) {
                 return annotation;
-            } else {
-                currentType = currentType.getSuperclass();
+            }
+        } else {
+            // Find from the class hierarchy
+            Class<?> currentType = clazz;
+            while (currentType != Object.class) {
+                T annotation = currentType.getAnnotation(annotationType);
+                if (annotation != null) {
+                    return annotation;
+                } else {
+                    currentType = currentType.getSuperclass();
+                }
             }
         }
 
-        // Find from an implemented interface
+        // Find from a directly implemented interface
         for (Class<?> iface : clazz.getInterfaces()) {
             T annotation = iface.getAnnotation(annotationType);
             if (annotation != null) {
diff --git a/server/tests/src/com/vaadin/server/UIProviderTest.java b/server/tests/src/com/vaadin/server/UIProviderTest.java
new file mode 100644
index 0000000000..579a3f1858
--- /dev/null
+++ b/server/tests/src/com/vaadin/server/UIProviderTest.java
@@ -0,0 +1,113 @@
+/*
+ * Copyright 2000-2014 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.server;
+
+import java.lang.annotation.ElementType;
+import java.lang.annotation.Retention;
+import java.lang.annotation.RetentionPolicy;
+import java.lang.annotation.Target;
+
+import org.junit.Assert;
+import org.junit.Test;
+
+import com.vaadin.annotations.Theme;
+import com.vaadin.annotations.Widgetset;
+
+/**
+ * Tests for {@link UIProvider} class.
+ * 
+ * @author Vaadin Ltd
+ */
+public class UIProviderTest {
+
+    @Test
+    public void getAnnotationFor_widgetsetAnnotationForSubclass_annotationFound() {
+        Assert.assertNotNull("Widgetset annotation is not found for subclass",
+                UIProvider.getAnnotationFor(TestClass.class, Widgetset.class));
+    }
+
+    @Test
+    public void getAnnotationFor_themeAnnotationForSubclass_annotationFound() {
+        Assert.assertNotNull("Theme annotation is not found for subclass",
+                UIProvider.getAnnotationFor(TestClass.class, Theme.class));
+    }
+
+    @Test
+    public void getAnnotationFor_themeAnnotationForSubclass_annotationOverridden() {
+        Assert.assertEquals(
+                "Theme annotation is not overridden correctly in subclass",
+                "c", UIProvider.getAnnotationFor(TestClass.class, Theme.class)
+                        .value());
+    }
+
+    @Test
+    public void getAnnotationFor_notInheritedAnnotationForSubclass_annotationFound() {
+        Assert.assertNotNull(
+                "TestAnnotation annotation is not found for subclass",
+                UIProvider.getAnnotationFor(TestClass.class,
+                        TestAnnotation.class));
+    }
+
+    @Test
+    public void getAnnotationFor_directAnnotationForSubclass_annotationFound() {
+        Assert.assertNotNull(
+                "TestAnnotation1 annotation is not found for subclass",
+                UIProvider.getAnnotationFor(TestClass.class,
+                        TestAnnotation1.class));
+    }
+
+    @Test
+    public void getAnnotationFor_annotationInheritedFromInterface_annotationFound() {
+        Assert.assertNotNull(
+                "Theme annotation is not inherited from interface", UIProvider
+                        .getAnnotationFor(ClassImplementingInterface.class,
+                                Theme.class));
+    }
+
+    @Retention(RetentionPolicy.RUNTIME)
+    @Target(ElementType.TYPE)
+    public @interface TestAnnotation {
+
+    }
+
+    @Retention(RetentionPolicy.RUNTIME)
+    @Target(ElementType.TYPE)
+    public @interface TestAnnotation1 {
+
+    }
+
+    @Widgetset("a")
+    @Theme("b")
+    @TestAnnotation
+    public static class TestSuperClass {
+
+    }
+
+    @TestAnnotation1
+    @Theme("c")
+    public static class TestClass extends TestSuperClass {
+
+    }
+
+    @Theme("d")
+    public interface InterfaceWithAnnotation {
+    }
+
+    public static class ClassImplementingInterface implements
+            InterfaceWithAnnotation {
+    }
+
+}