From 5ede0e91dbfff557333937fd6c816c96ae7b9da0 Mon Sep 17 00:00:00 2001
From: Sam Wright <samuel.wright314@gmail.com>
Date: Tue, 20 Oct 2015 17:49:46 +0100
Subject: [PATCH] #664 Annotate mapper implementations with @Singleton when
 using jsr330.

---
 .../src/main/java/org/mapstruct/DecoratedWith.java     |  6 +++---
 core-common/src/main/java/org/mapstruct/Mapper.java    |  2 +-
 .../src/main/java/org/mapstruct/MapperConfig.java      |  2 +-
 .../org/mapstruct/itest/jsr330/other/DateMapper.java   |  2 ++
 .../internal/processor/Jsr330ComponentProcessor.java   | 10 +++++++---
 5 files changed, 14 insertions(+), 8 deletions(-)

diff --git a/core-common/src/main/java/org/mapstruct/DecoratedWith.java b/core-common/src/main/java/org/mapstruct/DecoratedWith.java
index c3b3d191a..095fdccf8 100644
--- a/core-common/src/main/java/org/mapstruct/DecoratedWith.java
+++ b/core-common/src/main/java/org/mapstruct/DecoratedWith.java
@@ -123,9 +123,9 @@ import java.lang.annotation.Target;
  * <p>
  * JSR 330 doesn't specify qualifiers and only allows to specifically name the beans. Hence, the generated
  * implementation of the original mapper is annotated with {@code @Named("fully-qualified-name-of-generated-impl")}
- * (please note that when using a decorator, the class name of the mapper implementation ends with an underscore). To
- * inject that bean in your decorator, add the same annotation to the delegate field (e.g. by copy/pasting it from the
- * generated class):
+ * and {@code @Singleton} (please note that when using a decorator, the class name of the mapper implementation ends
+ * with an underscore). To inject that bean in your decorator, add the same annotation to the delegate field (e.g. by
+ * copy/pasting it from the generated class):
  *
  * <pre>
  * public abstract class PersonMapperDecorator implements PersonMapper {
diff --git a/core-common/src/main/java/org/mapstruct/Mapper.java b/core-common/src/main/java/org/mapstruct/Mapper.java
index 4406e72d3..6428cb114 100644
--- a/core-common/src/main/java/org/mapstruct/Mapper.java
+++ b/core-common/src/main/java/org/mapstruct/Mapper.java
@@ -75,7 +75,7 @@ public @interface Mapper {
      * can be retrieved via {@code @Autowired}</li>
      * <li>
      * {@code jsr330}: the generated mapper is annotated with {@code @Named} and
-     * can be retrieved via {@code @Inject}</li>
+     * {@code @Singleton}, and can be retrieved via {@code @Inject}</li>
      * </ul>
      * The method overrides an unmappedTargetPolicy set in a central configuration set
      * by {@link #config() }
diff --git a/core-common/src/main/java/org/mapstruct/MapperConfig.java b/core-common/src/main/java/org/mapstruct/MapperConfig.java
index 183ba25d4..d6a2ad243 100644
--- a/core-common/src/main/java/org/mapstruct/MapperConfig.java
+++ b/core-common/src/main/java/org/mapstruct/MapperConfig.java
@@ -77,7 +77,7 @@ public @interface MapperConfig {
      * can be retrieved via {@code @Autowired}</li>
      * <li>
      * {@code jsr330}: the generated mapper is annotated with {@code @Named} and
-     * can be retrieved via {@code @Inject}</li>
+     * {@code @Singleton}, and can be retrieved via {@code @Inject}</li>
      * </ul>
      *
      * @return The component model for the generated mapper.
diff --git a/integrationtest/src/test/resources/jsr330Test/src/main/java/org/mapstruct/itest/jsr330/other/DateMapper.java b/integrationtest/src/test/resources/jsr330Test/src/main/java/org/mapstruct/itest/jsr330/other/DateMapper.java
index 683b708c1..895aa4c41 100644
--- a/integrationtest/src/test/resources/jsr330Test/src/main/java/org/mapstruct/itest/jsr330/other/DateMapper.java
+++ b/integrationtest/src/test/resources/jsr330Test/src/main/java/org/mapstruct/itest/jsr330/other/DateMapper.java
@@ -23,7 +23,9 @@ import java.text.SimpleDateFormat;
 import java.util.Date;
 
 import javax.inject.Named;
+import javax.inject.Singleton;
 
+@Singleton
 @Named
 public class DateMapper {
 
diff --git a/processor/src/main/java/org/mapstruct/ap/internal/processor/Jsr330ComponentProcessor.java b/processor/src/main/java/org/mapstruct/ap/internal/processor/Jsr330ComponentProcessor.java
index 75315f625..05b8020aa 100644
--- a/processor/src/main/java/org/mapstruct/ap/internal/processor/Jsr330ComponentProcessor.java
+++ b/processor/src/main/java/org/mapstruct/ap/internal/processor/Jsr330ComponentProcessor.java
@@ -42,16 +42,16 @@ public class Jsr330ComponentProcessor extends AnnotationBasedComponentModelProce
     @Override
     protected List<Annotation> getTypeAnnotations(Mapper mapper) {
         if ( mapper.getDecorator() == null ) {
-            return Collections.singletonList( named() );
+            return Arrays.asList( singleton(), named() );
         }
         else {
-            return Collections.singletonList( namedDelegate( mapper ) );
+            return Arrays.asList( singleton(), namedDelegate( mapper ) );
         }
     }
 
     @Override
     protected List<Annotation> getDecoratorAnnotations() {
-        return Collections.singletonList( named() );
+        return Arrays.asList( singleton(), named() );
     }
 
     @Override
@@ -69,6 +69,10 @@ public class Jsr330ComponentProcessor extends AnnotationBasedComponentModelProce
         return true;
     }
 
+    private Annotation singleton() {
+        return new Annotation( getTypeFactory().getType( "javax.inject.Singleton" ) );
+    }
+
     private Annotation named() {
         return new Annotation( getTypeFactory().getType( "javax.inject.Named" ) );
     }