From 4e646605b621dcc6a65ffd8793a864abf6078b11 Mon Sep 17 00:00:00 2001
From: Denis Anisimov <denis@vaadin.com>
Date: Sat, 22 Nov 2014 12:27:01 +0200
Subject: [PATCH] Use @Inherited for annotations that have inherited semantic
 (#12351).

Change-Id: I70f0d79095bfd05b83905df6a3eedd1a5e93b48e
---
 WebContent/release-notes.html                 |   2 +
 .../vaadin/annotations/PreserveOnRefresh.java |   2 +
 server/src/com/vaadin/annotations/Push.java   |   2 +
 server/src/com/vaadin/annotations/Theme.java  |   2 +
 server/src/com/vaadin/annotations/Title.java  |   2 +
 .../VaadinServletConfiguration.java           |   2 +
 .../src/com/vaadin/annotations/Widgetset.java |   2 +
 server/src/com/vaadin/server/UIProvider.java  |  34 ++++--
 .../src/com/vaadin/server/UIProviderTest.java | 113 ++++++++++++++++++
 9 files changed, 152 insertions(+), 9 deletions(-)
 create mode 100644 server/tests/src/com/vaadin/server/UIProviderTest.java

diff --git a/WebContent/release-notes.html b/WebContent/release-notes.html
index bccb867c4d..debf544ed5 100644
--- a/WebContent/release-notes.html
+++ b/WebContent/release-notes.html
@@ -147,6 +147,8 @@
                 This default can be changed in deployment configuration.</li>
             <li>Server-side timings of request processing are only sent to the client when not in production mode. Using the
                 timings in TestBench tests requires the server not to be in production mode.</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 {
+    }
+
+}
-- 
2.39.5