Patch to enable hacky keyserializer support for CaseClasses in the Jackson Scala module

keySerializers.patch

From 5ec37ea1d859430b950cf49c8bba5bf8499522cc Mon Sep 17 00:00:00 2001
From: Jesse C <crimson.corelio@gmail.com>
Date: Mon, 13 Aug 2012 14:36:51 -0400
Subject: [PATCH] Hacky proof-of-concept for keySerializers in caseClasses

---
 .../scala/deser/CaseClassDeserializerModule.scala  | 41 ++++++++++++++++++++--
 .../module/scala/ser/MapSerializerModule.scala     | 23 ++++++++++--
 2 files changed, 58 insertions(+), 6 deletions(-)

diff --git a/src/main/scala/com/fasterxml/jackson/module/scala/deser/CaseClassDeserializerModule.scala b/src/main/scala/com/fasterxml/jackson/module/scala/deser/CaseClassDeserializerModule.scala
index bdc2884..1736d69 100644
--- a/src/main/scala/com/fasterxml/jackson/module/scala/deser/CaseClassDeserializerModule.scala
+++ b/src/main/scala/com/fasterxml/jackson/module/scala/deser/CaseClassDeserializerModule.scala
@@ -2,10 +2,10 @@ package com.fasterxml.jackson.module.scala.deser
 
 import com.fasterxml.jackson.module.scala.JacksonModule
 import com.fasterxml.jackson.module.scala.util.ScalaBeansUtil
-
-import com.fasterxml.jackson.databind.introspect.{AnnotatedField, AnnotatedConstructor, AnnotatedParameter, NopAnnotationIntrospector};
-
+import com.fasterxml.jackson.databind.introspect.{Annotated, AnnotatedField, AnnotatedConstructor, AnnotatedParameter, NopAnnotationIntrospector}
 import org.scalastuff.scalabeans.{DeserializablePropertyDescriptor, ConstructorParameter}
+import com.fasterxml.jackson.databind.introspect.AnnotatedMethod
+import com.fasterxml.jackson.databind.annotation.JsonSerialize
 
 private object CaseClassAnnotationIntrospector extends NopAnnotationIntrospector {
   lazy val PRODUCT = classOf[Product]
@@ -19,6 +19,39 @@ private object CaseClassAnnotationIntrospector extends NopAnnotationIntrospector
     else if (cls.getName.startsWith("scala.Tuple")) false
     else true
   }
+  
+  override def findKeySerializer(a: Annotated): Object = {
+    a match {
+      // If we're serializing a method, see if we have a constructor arg with the
+      // same name (we should).  That will have any applicable annotations on it.
+      case am: AnnotatedMethod => {
+        val cls = am.getDeclaringClass
+        if (!maybeIsCaseClass(cls)) null
+        else {
+          val fieldName = am.getName
+          val properties = ScalaBeansUtil.propertiesOf(cls)
+          properties.find {
+            case cp: ConstructorParameter => fieldName == cp.name
+            case _ => false
+          } match {
+            case Some(prop) =>  {
+              val cp = prop.asInstanceOf[ConstructorParameter]
+              val idx = cp.index
+              val constructors = cls.getConstructors()
+              val paramAnnots = constructors.head.getParameterAnnotations
+              val pa = paramAnnots(idx)
+              val annot = pa.find {
+                case a => a.annotationType() == classOf[JsonSerialize]
+              }
+              annot.map(a => a.asInstanceOf[JsonSerialize].keyUsing) getOrElse null
+            } 
+            case None => null
+          }
+        } 
+      }
+     case _ => null
+    }
+  }
 
   override def findDeserializationName(af: AnnotatedField): String = {
     val cls = af.getDeclaringClass
@@ -32,6 +65,8 @@ private object CaseClassAnnotationIntrospector extends NopAnnotationIntrospector
       } map (_.name) getOrElse null
     }
   }
+  
+  
 
   override def findDeserializationName(param: AnnotatedParameter): String = {
     val cls = param.getDeclaringClass
diff --git a/src/main/scala/com/fasterxml/jackson/module/scala/ser/MapSerializerModule.scala b/src/main/scala/com/fasterxml/jackson/module/scala/ser/MapSerializerModule.scala
index 58c7366..bbb8211 100644
--- a/src/main/scala/com/fasterxml/jackson/module/scala/ser/MapSerializerModule.scala
+++ b/src/main/scala/com/fasterxml/jackson/module/scala/ser/MapSerializerModule.scala
@@ -12,12 +12,26 @@ import com.fasterxml.jackson.databind.`type`.MapLikeType;
 
 import com.fasterxml.jackson.module.scala.modifiers.MapTypeModifierModule;
 
-private class MapSerializer
+private class MapSerializer(val keySerializer: JsonSerializer[AnyRef])
   extends JsonSerializer[Map[_,_]]
 {
   def serialize(value: Map[_, _], jgen: JsonGenerator, provider: SerializerProvider) {
     jgen.writeStartObject()
-    value.foreach { case (k,v) => jgen.writeObjectField(k.toString,v) }
+    value.foreach { case (k,v) => {
+      if (keySerializer == null) {
+        jgen.writeObjectField(k.toString,v) 
+      }
+      else {
+        k match {
+          case a: AnyRef => {
+            keySerializer.serialize(a, jgen, provider)
+            jgen.writeObject(v)
+          } 
+          case _ => jgen.writeObjectField(k.toString,v)
+        }
+        
+     } 
+    }}
     jgen.writeEndObject()
   }
 
@@ -37,9 +51,12 @@ private object MapSerializerResolver extends Serializers.Base {
 
 
     val rawClass = mapLikeType.getRawClass
+    
+    val keyType = mapLikeType.getKeyType
+    val handler = keyType.getValueHandler[Object]
 
     if (!BASE.isAssignableFrom(rawClass)) null
-    else new MapSerializer
+    else new MapSerializer(keySerializer)
   }
 
 }
-- 
1.7.11.2