Json4s integration, fixes #121 (#123)

lloydmeta · Mar 7, 2017 · 260ffe7 · 260ffe7
1 parent de3c252
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diff --git a/README.md b/README.md
@@ -31,6 +31,7 @@ Integrations are available for:
 - [UPickle](http://www.lihaoyi.com/upickle-pprint/upickle/): JVM and ScalaJS
 - [ReactiveMongo BSON](http://reactivemongo.org/releases/0.11/documentation/bson/overview.html): JVM only
 - [Argonaut](http://www.argonaut.io): JVM only
+- [Json4s](http://json4s.org): JVM only
 
 ### Table of Contents
 
@@ -750,6 +751,63 @@ ArgonautDevice.values.foreach { item =>
 }
 ```
 
+## Json4s
+[![Maven Central](https://maven-badges.herokuapp.com/maven-central/com.beachape/enumeratum-json4s_2.11/badge.svg)](https://maven-badges.herokuapp.com/maven-central/com.beachape/enumeratum-json4s_2.11)
+
+### SBT
+
+To use enumeratum with [Json4s](http://json4s.org):
+
+```scala
+libraryDependencies ++= Seq(
+    "com.beachape" %% "enumeratum-json4s" % enumeratumVersion
+)
+```
+
+### Usage
+
+#### Enum
+
+```scala
+import enumeratum._
+
+sealed trait TrafficLight extends EnumEntry
+object TrafficLight extends Enum[TrafficLight] /* nothing extra here */ {
+  case object Red    extends TrafficLight
+  case object Yellow extends TrafficLight
+  case object Green  extends TrafficLight
+
+  val values = findValues
+}
+
+import org.json4s.DefaultFormats
+
+implicit val formats = DefaultFormats + Json4s.serializer(TrafficLight)
+
+```
+
+#### ValueEnum
+
+```scala
+import enumeratum.values._
+
+sealed abstract class Device(val value: Short) extends ShortEnumEntry
+case object Device
+  extends ShortEnum[Device] /* nothing extra here */  {
+  case object Phone   extends Device(1)
+  case object Laptop  extends Device(2)
+  case object Desktop extends Device(3)
+  case object Tablet  extends Device(4)
+
+  val values = findValues
+}
+
+import org.json4s.DefaultFormats
+
+implicit val formats = DefaultFormats + Json4s.serializer(Device)
+
+```
+
 ## Slick integration
 
 [Slick](http://slick.lightbend.com) doesn't have a separate integration at the moment. You just have to provide a `MappedColumnType` for each database column that should be represented as an enum on the Scala side.

diff --git a/build.sbt b/build.sbt
@@ -16,6 +16,7 @@ lazy val reactiveMongoVersion = "0.12.1"
 lazy val circeVersion         = "0.7.0"
 lazy val uPickleVersion       = "0.4.4"
 lazy val argonautVersion      = "6.2-RC2"
+lazy val json4sVersion        = "3.5.0"
 def thePlayVersion(scalaVersion: String) =
   CrossVersion.partialVersion(scalaVersion) match {
     case Some((2, scalaMajor)) if scalaMajor >= 11 => "2.5.12"
@@ -35,7 +36,8 @@ lazy val integrationProjectRefs = Seq(
   enumeratumCirceJs,
   enumeratumCirceJvm,
   enumeratumReactiveMongoBson,
-  enumeratumArgonaut
+  enumeratumArgonaut,
+  enumeratumJson4s
 ).map(Project.projectToRef)
 
 lazy val root =
@@ -76,6 +78,7 @@ lazy val scala_2_12 = Project(id = "scala_2_12",
         enumeratumUPickleJs,
         enumeratumUPickleJvm,
         enumeratumArgonaut,
+        enumeratumJson4s,
         enumeratumReactiveMongoBson
       ).map(Project.projectToRef): _*) // base plus known 2.12 friendly libs
 
@@ -275,6 +278,21 @@ lazy val enumeratumArgonaut =
       )
     )
 
+lazy val enumeratumJson4s =
+  Project(id = "enumeratum-json4s",
+          base = file("enumeratum-json4s"),
+          settings = commonWithPublishSettings)
+    .settings(testSettings: _*)
+    .settings(
+      version := "1.5.9-SNAPSHOT",
+      crossScalaVersions := scalaVersionsAll,
+      libraryDependencies ++= Seq(
+        "org.json4s"   %% "json4s-core"   % json4sVersion,
+        "org.json4s"   %% "json4s-native" % json4sVersion        % "test",
+        "com.beachape" %% "enumeratum"    % Versions.Core.stable
+      )
+    )
+
 lazy val commonSettings = Seq(
     organization := "com.beachape",
     incOptions := incOptions.value.withLogRecompileOnMacro(false),

diff --git a/enumeratum-json4s/src/main/scala/enumeratum/Json4s.scala b/enumeratum-json4s/src/main/scala/enumeratum/Json4s.scala
@@ -0,0 +1,18 @@
+package enumeratum
+
+import org.json4s.CustomSerializer
+import org.json4s.JsonAST.JString
+
+@SuppressWarnings(Array("org.wartremover.warts.Any"))
+object Json4s {
+
+  def serializer[A <: EnumEntry: Manifest](enum: Enum[A]): CustomSerializer[A] = new CustomSerializer[A](_ => (
+    {
+      case JString(s) if enum.withNameOption(s).isDefined => enum.withName(s)
+    },
+    {
+      case x: A => JString(x.entryName)
+    }
+  ))
+
+}
diff --git a/enumeratum-json4s/src/main/scala/enumeratum/values/Json4s.scala b/enumeratum-json4s/src/main/scala/enumeratum/values/Json4s.scala
@@ -0,0 +1,67 @@
+package enumeratum.values
+
+import org.json4s.CustomSerializer
+import org.json4s.JsonAST.{JInt, JLong, JString}
+
+@SuppressWarnings(Array("org.wartremover.warts.Any"))
+object Json4s {
+
+  def serializer[A <: IntEnumEntry: Manifest](enum: IntEnum[A]): CustomSerializer[A] = new CustomSerializer[A](_ => (
+    {
+      case JInt(i) if i <= Int.MaxValue && enum.withValueOpt(i.toInt).isDefined => enum.withValue(i.toInt)
+      case JLong(i) if i <= Int.MaxValue && enum.withValueOpt(i.toInt).isDefined => enum.withValue(i.toInt)
+    },
+    {
+      case x: A => JLong(x.value.toLong)
+    }
+  ))
+
+  def serializer[A <: LongEnumEntry: Manifest](enum: LongEnum[A]): CustomSerializer[A] = new CustomSerializer[A](_ => (
+    {
+      case JInt(i) if enum.withValueOpt(i.toLong).isDefined => enum.withValue(i.toLong)
+      case JLong(i) if enum.withValueOpt(i).isDefined => enum.withValue(i)
+    },
+    {
+      case x: A => JLong(x.value)
+    }
+  ))
+
+  def serializer[A <: ShortEnumEntry: Manifest](enum: ShortEnum[A]): CustomSerializer[A] = new CustomSerializer[A](_ => (
+    {
+      case JInt(i) if i <= Short.MaxValue.toInt && enum.withValueOpt(i.toShort).isDefined => enum.withValue(i.toShort)
+      case JLong(i) if i <= Short.MaxValue && enum.withValueOpt(i.toShort).isDefined => enum.withValue(i.toShort)
+    },
+    {
+      case x: A => JLong(x.value.toLong)
+    }
+  ))
+
+  def serializer[A <: StringEnumEntry: Manifest](enum: StringEnum[A]): CustomSerializer[A] = new CustomSerializer[A](_ => (
+    {
+      case JString(s) if enum.withValueOpt(s).isDefined => enum.withValue(s)
+    },
+    {
+      case x: A => JString(x.value)
+    }
+  ))
+
+  def serializer[A <: ByteEnumEntry: Manifest](enum: ByteEnum[A]): CustomSerializer[A] = new CustomSerializer[A](_ => (
+    {
+      case JInt(i) if i <= Byte.MaxValue.toInt && enum.withValueOpt(i.toByte).isDefined => enum.withValue(i.toByte)
+      case JLong(i) if i <= Byte.MaxValue && enum.withValueOpt(i.toByte).isDefined => enum.withValue(i.toByte)
+    },
+    {
+      case x: A => JLong(x.value.toLong)
+    }
+  ))
+
+  def serializer[A <: CharEnumEntry: Manifest](enum: CharEnum[A]): CustomSerializer[A] = new CustomSerializer[A](_ => (
+    {
+      case JString(s) if s.length == 1 && enum.withValueOpt(s.head).isDefined => enum.withValue(s.head)
+    },
+    {
+      case x: A => JString(x.value.toString)
+    }
+  ))
+
+}
diff --git a/enumeratum-json4s/src/test/scala/enumeratum/Json4sSpec.scala b/enumeratum-json4s/src/test/scala/enumeratum/Json4sSpec.scala
@@ -0,0 +1,65 @@
+package enumeratum
+
+import org.json4s.{DefaultFormats, MappingException}
+import org.json4s.native.Serialization
+import org.scalatest.{FunSpec, Matchers}
+
+class Json4sSpec extends FunSpec with Matchers {
+
+  implicit val formats = DefaultFormats + Json4s.serializer(TrafficLight)
+
+  case class Data(tr: TrafficLight)
+  case class DataOpt(tr: Option[TrafficLight])
+
+  describe("to JSON") {
+    it("should serialize plain value to entryName") {
+      TrafficLight.values.foreach { value =>
+        Serialization.write(Data(tr = value)) shouldBe ("""{"tr":"""" + value.entryName + """"}""")
+      }
+    }
+
+    it("should serialize Some(value) to entryName") {
+      TrafficLight.values.foreach { value =>
+        Serialization.write(DataOpt(tr = Some(value))) shouldBe ("""{"tr":"""" + value.entryName + """"}""")
+      }
+    }
+
+    it("should serialize None to nothing") {
+      Serialization.write(DataOpt(tr = None)) shouldBe """{}"""
+    }
+  }
+
+  describe("from JSON") {
+    it("should parse enum members when given proper encoding") {
+      TrafficLight.values.foreach { value =>
+        Serialization.read[Data]("""{"tr":"""" + value.entryName + """"}""").tr shouldBe value
+      }
+    }
+
+    it("should parse enum members into optional values") {
+      TrafficLight.values.foreach { value =>
+        Serialization.read[DataOpt]("""{"tr":"""" + value.entryName + """"}""").tr shouldBe Some(value)
+      }
+    }
+
+    it("should parse missing value into None") {
+      Serialization.read[DataOpt]("""{}""").tr shouldBe None
+    }
+
+    it("should parse invalid value into None") {
+      Serialization.read[DataOpt]("""{"tr":"bogus"}""").tr shouldBe None
+      Serialization.read[DataOpt]("""{"tr":17}""").tr shouldBe None
+      Serialization.read[DataOpt]("""{"tr":true}""").tr shouldBe None
+      Serialization.read[DataOpt]("""{"tr":null}""").tr shouldBe None
+    }
+
+    it("should fail to parse random JSON values to members") {
+      a [MappingException] shouldBe thrownBy (Serialization.read[Data]("""{"tr":"bogus"}"""))
+      a [MappingException] shouldBe thrownBy (Serialization.read[Data]("""{"tr":17}"""))
+      a [MappingException] shouldBe thrownBy (Serialization.read[Data]("""{"tr":true}"""))
+      a [MappingException] shouldBe thrownBy (Serialization.read[Data]("""{"tr":null}"""))
+      a [MappingException] shouldBe thrownBy (Serialization.read[Data]("""{}"""))
+    }
+  }
+
+}
diff --git a/enumeratum-json4s/src/test/scala/enumeratum/TrafficLight.scala b/enumeratum-json4s/src/test/scala/enumeratum/TrafficLight.scala
@@ -0,0 +1,10 @@
+package enumeratum
+
+sealed trait TrafficLight extends EnumEntry
+object TrafficLight extends Enum[TrafficLight] {
+  case object Red    extends TrafficLight
+  case object Yellow extends TrafficLight
+  case object Green  extends TrafficLight
+
+  val values = findValues
+}