Simplify fieldName logic

src/main/scala/com/codahale/jerkson/ser/CaseClassSerializer.scala

@@ -14,7 +14,7 @@ class CaseClassSerializer[A <: Product](klass: Class[_]) extends JsonSerializer[
   private val ignoredFields = if (klass.isAnnotationPresent(classOf[JsonIgnoreProperties])) {
     klass.getAnnotation(classOf[JsonIgnoreProperties]).value().toSet
   } else Set.empty[String]
-  
+
   private val nonIgnoredFields = klass.getDeclaredFields.filterNot { f =>
     f.getAnnotation(classOf[JsonIgnore]) != null ||
     ignoredFields(f.getName) ||
@@ -25,14 +25,14 @@ class CaseClassSerializer[A <: Product](klass: Class[_]) extends JsonSerializer[
   private val methods = klass.getDeclaredMethods
                                 .filter { _.getParameterTypes.isEmpty }
                                 .map { m => m.getName -> m }.toMap
-  
+
   def serialize(value: A, json: JsonGenerator, provider: SerializerProvider) {
     json.writeStartObject()
     for (field <- nonIgnoredFields) {
-      val methodOpt = methods.get(field.getName)
+      val fieldName = field.getName
+      val methodOpt = methods.get(fieldName)
       val fieldValue: Object = methodOpt.map { _.invoke(value) }.getOrElse(field.get(value))
       if (fieldValue != None) {
-        val fieldName = methodOpt.map { _.getName }.getOrElse(field.getName)
         provider.defaultSerializeField(if (isSnakeCase) snakeCase(fieldName) else fieldName, fieldValue, json)
       }
     }