Annotations.findAnnotation() added

core/descriptors/src/org/jetbrains/jet/lang/descriptors/annotations/Annotations.java

@@ -17,6 +17,8 @@
 package org.jetbrains.jet.lang.descriptors.annotations;
 
 import org.jetbrains.annotations.NotNull;
+import org.jetbrains.annotations.Nullable;
+import org.jetbrains.jet.lang.resolve.name.FqName;
 
 import java.util.Collections;
 import java.util.Iterator;
@@ -28,6 +30,12 @@ public interface Annotations extends Iterable<AnnotationDescriptor> {
             return true;
         }
 
+        @Nullable
+        @Override
+        public AnnotationDescriptor findAnnotation(@NotNull FqName fqName) {
+            return null;
+        }
+
         @NotNull
         @Override
         public Iterator<AnnotationDescriptor> iterator() {
@@ -36,4 +44,7 @@ public interface Annotations extends Iterable<AnnotationDescriptor> {
     };
 
     boolean isEmpty();
+
+    @Nullable
+    AnnotationDescriptor findAnnotation(@NotNull FqName fqName);
 }

core/descriptors/src/org/jetbrains/jet/lang/descriptors/annotations/AnnotationsImpl.java

@@ -17,6 +17,11 @@
 package org.jetbrains.jet.lang.descriptors.annotations;
 
 import org.jetbrains.annotations.NotNull;
+import org.jetbrains.annotations.Nullable;
+import org.jetbrains.jet.lang.descriptors.ClassDescriptor;
+import org.jetbrains.jet.lang.descriptors.ClassifierDescriptor;
+import org.jetbrains.jet.lang.resolve.DescriptorUtils;
+import org.jetbrains.jet.lang.resolve.name.FqName;
 
 import java.util.Iterator;
 import java.util.List;
@@ -38,6 +43,18 @@ public class AnnotationsImpl implements Annotations {
         return getAnnotationDescriptors().isEmpty();
     }
 
+    @Nullable
+    @Override
+    public AnnotationDescriptor findAnnotation(@NotNull FqName fqName) {
+        for (AnnotationDescriptor annotation : annotations) {
+            ClassifierDescriptor descriptor = annotation.getType().getConstructor().getDeclarationDescriptor();
+            if (descriptor instanceof ClassDescriptor && fqName.toUnsafe().equals(DescriptorUtils.getFqName(descriptor))) {
+                return annotation;
+            }
+        }
+        return null;
+    }
+
     @NotNull
     @Override
     public Iterator<AnnotationDescriptor> iterator() {