New iterable serializer (#468)

Author: pjfanning

src/main/scala/com/fasterxml/jackson/module/scala/ser/IterableSerializerModule.scala

@@ -7,24 +7,22 @@ import java.{lang => jl}
 import com.fasterxml.jackson.core.JsonGenerator
 import com.fasterxml.jackson.databind.`type`.CollectionLikeType
 import com.fasterxml.jackson.databind.jsontype.TypeSerializer
-import com.fasterxml.jackson.databind.ser.std.{AsArraySerializerBase, CollectionSerializer}
+import com.fasterxml.jackson.databind.ser.std.AsArraySerializerBase
 import com.fasterxml.jackson.databind.ser.{ContainerSerializer, Serializers}
 import com.fasterxml.jackson.databind._
 import com.fasterxml.jackson.module.scala.modifiers.IterableTypeModifierModule
 
-import scala.collection.JavaConverters._
-
 private trait IterableSerializer
   extends AsArraySerializerBase[collection.Iterable[Any]]
 {
-  def collectionSerializer: CollectionSerializer
+  def collectionSerializer: ScalaIterableSerializer
 
   override def hasSingleElement(value: collection.Iterable[Any]): Boolean = {
     value.size == 1
   }
 
   override def serializeContents(value: collection.Iterable[Any], gen: JsonGenerator, provider: SerializerProvider): Unit = {
-    collectionSerializer.serializeContents(value.asJavaCollection, gen, provider)
+    collectionSerializer.serializeContents(value, gen, provider)
   }
 
   override def withResolved(property: BeanProperty,
@@ -45,7 +43,7 @@ private class ResolvedIterableSerializer( src: IterableSerializer,
   with IterableSerializer
 {
   val collectionSerializer =
-    new CollectionSerializer(src.collectionSerializer, property, vts, elementSerializer, unwrapSingle)
+    new ScalaIterableSerializer(src.collectionSerializer, property, vts, elementSerializer)
 
   override def _withValueTypeSerializer(newVts: TypeSerializer): ContainerSerializer[_] =
     new ResolvedIterableSerializer(this, property, newVts, elementSerializer, unwrapSingle)
@@ -61,7 +59,7 @@ private class UnresolvedIterableSerializer( cls: Class[_],
   with IterableSerializer
 {
   val collectionSerializer =
-    new CollectionSerializer(et, staticTyping, vts, elementSerializer)
+    new ScalaIterableSerializer(et, staticTyping, vts, elementSerializer)
 
   override def _withValueTypeSerializer(newVts: TypeSerializer): ContainerSerializer[_] =
     new UnresolvedIterableSerializer(cls, et, staticTyping, newVts, elementSerializer)

src/main/scala/com/fasterxml/jackson/module/scala/ser/ScalaIterableSerializer.scala

@@ -0,0 +1,101 @@
+package com.fasterxml.jackson.module.scala.ser
+
+import java.{lang => jl}
+
+import com.fasterxml.jackson.core.JsonGenerator
+import com.fasterxml.jackson.databind.jsontype.TypeSerializer
+import com.fasterxml.jackson.databind.ser.ContainerSerializer
+import com.fasterxml.jackson.databind.ser.std.AsArraySerializerBase
+import com.fasterxml.jackson.databind.{BeanProperty, JavaType, JsonSerializer, SerializationFeature, SerializerProvider}
+
+case class ScalaIterableSerializer(elemType: JavaType, staticTyping: Boolean, vts: TypeSerializer,
+                                   property: BeanProperty, valueSerializer: JsonSerializer[Object])
+  extends AsArraySerializerBase[collection.Iterable[Any]](collection.Iterable.getClass, elemType, staticTyping, vts, property, valueSerializer) {
+
+  def this(elemType: JavaType, staticTyping: Boolean, vts: TypeSerializer, valueSerializer: JsonSerializer[Object]) {
+    this(elemType, staticTyping, vts, None.orNull, valueSerializer.asInstanceOf[JsonSerializer[Object]])
+  }
+
+  def this(src: ScalaIterableSerializer, property: BeanProperty, vts: TypeSerializer, valueSerializer: JsonSerializer[_]) {
+    this(src.elemType, src.staticTyping, vts, property, valueSerializer.asInstanceOf[JsonSerializer[Object]])
+  }
+
+  override def isEmpty(prov: SerializerProvider, value: Iterable[Any]): Boolean = value.isEmpty
+
+  override def hasSingleElement(value: Iterable[Any]): Boolean = value.size == 1
+
+  override def serialize(value: Iterable[Any], g: JsonGenerator, provider: SerializerProvider): Unit = {
+    val len: Int = value.size
+    if (len == 1 &&
+        (_unwrapSingle == null && provider.isEnabled(SerializationFeature.WRITE_SINGLE_ELEM_ARRAYS_UNWRAPPED)) || (_unwrapSingle)) {
+      serializeContents(value, g, provider)
+    } else {
+      g.writeStartArray(value, len)
+      serializeContents(value, g, provider)
+      g.writeEndArray()
+    }
+  }
+
+  override def serializeContents(value: Iterable[Any], g: JsonGenerator, provider: SerializerProvider): Unit = {
+    g.setCurrentValue(value)
+    if (_elementSerializer != null) {
+      serializeContentsUsing(value, g, provider, _elementSerializer)
+    } else {
+      val it = value.iterator
+      if (it.hasNext) {
+        val typeSer = _valueTypeSerializer
+        var serializers = _dynamicSerializers
+        var i = 0
+        try do {
+          val elem = it.next
+          if (elem == null) provider.defaultSerializeNull(g)
+          else {
+            val cc = elem.getClass
+            var serializer = serializers.serializerFor(cc)
+            if (serializer == null) {
+              if (_elementType.hasGenericTypes) serializer = _findAndAddDynamic(serializers, provider.constructSpecializedType(_elementType, cc), provider)
+              else serializer = _findAndAddDynamic(serializers, cc, provider)
+              serializers = _dynamicSerializers
+            }
+            if (typeSer == null) serializer.serialize(elem.asInstanceOf[Object], g, provider)
+            else serializer.serializeWithType(elem.asInstanceOf[Object], g, provider, typeSer)
+          }
+          i += 1
+        } while (it.hasNext)
+        catch {
+          case e: Exception =>
+            wrapAndThrow(provider, e, value, i)
+        }
+      }
+    }
+  }
+
+  override def withResolved(property: BeanProperty, vts: TypeSerializer, elementSerializer: JsonSerializer[_],
+                            unwrapSingle: jl.Boolean): AsArraySerializerBase[Iterable[Any]] = {
+    new ScalaIterableSerializer(this, property, vts, elementSerializer)
+  }
+
+  override def _withValueTypeSerializer(vts: TypeSerializer): ContainerSerializer[_] = {
+    new ScalaIterableSerializer(this, _property, vts, _elementSerializer)
+  }
+
+  private def serializeContentsUsing(value: Iterable[Any], g: JsonGenerator, provider: SerializerProvider, ser: JsonSerializer[AnyRef]): Unit = {
+    val it = value.iterator
+    if (it.hasNext) {
+      val typeSer = _valueTypeSerializer
+      var i = 0
+      do {
+        val elem = it.next
+        try {
+          if (elem == null) provider.defaultSerializeNull(g)
+          else if (typeSer == null) ser.serialize(elem.asInstanceOf[Object], g, provider)
+          else ser.serializeWithType(elem.asInstanceOf[Object], g, provider, typeSer)
+          i += 1
+        } catch {
+          case e: Exception =>
+            wrapAndThrow(provider, e, value, i)
+        }
+      } while (it.hasNext)
+    }
+  }
+}