#22 - better serialisation for Tuples

src/main/scala/com/codahale/jerkson/deser/ScalaDeserializers.scala

@@ -6,6 +6,7 @@ import com.codahale.jerkson.AST.{JNull, JValue}
 import scala.collection.generic.{MapFactory, GenericCompanion}
 import com.fasterxml.jackson.databind.deser.Deserializers
 import com.fasterxml.jackson.databind.Module.SetupContext
+import com.codahale.jerkson.ser.TupleSerializer
 
 class ScalaDeserializers(classLoader: ClassLoader, context: SetupContext) extends Deserializers.Base {
   override def findBeanDeserializer(javaType: JavaType, config: DeserializationConfig,
@@ -88,6 +89,8 @@ class ScalaDeserializers(classLoader: ClassLoader, context: SetupContext) extend
       new BigDecimalDeserializer
     } else if (klass == classOf[Either[_,_]]) {
       new EitherDeserializer(config, javaType)
+    } else if (TupleSerializer.allTupleClasses.exists(_.isAssignableFrom(beanDesc.getBeanClass()))) {
+      new TupleDeserializer(javaType)
     } else if (classOf[Product].isAssignableFrom(klass)) {
       new CaseClassDeserializer(config, javaType, classLoader)
     } else null

src/main/scala/com/codahale/jerkson/deser/TupleDeserializer.scala

@@ -0,0 +1,38 @@
+package com.codahale.jerkson.deser
+import com.fasterxml.jackson.databind.JsonDeserializer
+import com.fasterxml.jackson.databind.DeserializationContext
+import com.fasterxml.jackson.core.JsonParser
+import com.fasterxml.jackson.core.JsonToken
+import com.fasterxml.jackson.databind.node.TreeTraversingParser
+import com.fasterxml.jackson.databind.JsonNode
+import com.fasterxml.jackson.databind.`type`.SimpleType
+import com.fasterxml.jackson.databind.JavaType
+import com.codahale.jerkson.ser.TupleSerializer
+
+class TupleDeserializer(javaType: JavaType) extends JsonDeserializer[Product] {
+  val types = for (i <- 0 until javaType.containedTypeCount()) yield javaType.containedType(i)
+
+  def deserialize(jp: JsonParser, ctxt: DeserializationContext): Product = {
+    if (jp.getCurrentToken != JsonToken.START_ARRAY) {
+      throw ctxt.mappingException("Tuple expected as an array")
+    }
+
+    val builder = collection.mutable.ListBuffer[Object]()
+
+    for (t <- types) {
+      jp.nextToken()
+      val elementDeserializer = ctxt.findRootValueDeserializer(t)
+      builder += elementDeserializer.deserialize(jp, ctxt)
+    }
+
+    if (jp.nextToken() != JsonToken.END_ARRAY) {
+      throw ctxt.mappingException("More elements than expected for Tuple" + types.size)
+    }
+
+    val c: Class[_ <: Product] = TupleSerializer.allTupleClasses(types.size - 1)
+
+    val consArgs = for (n <- 1 to types.size) yield classOf[Object]
+
+    c.getConstructor(consArgs: _*).newInstance(builder.toArray: _*)
+  }
+}

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

@@ -22,6 +22,8 @@ class ScalaSerializers extends Serializers.Base {
       new JValueSerializer
     } else if (classOf[Either[_,_]].isAssignableFrom(beanDesc.getBeanClass)) {
       new EitherSerializer
+    } else if (TupleSerializer.allTupleClasses.exists(_.isAssignableFrom(beanDesc.getBeanClass()))) {
+      new TupleSerializer
     } else if (classOf[Product].isAssignableFrom(beanDesc.getBeanClass)) {
       new CaseClassSerializer(beanDesc.getBeanClass)
     } else {

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

@@ -0,0 +1,42 @@
+package com.codahale.jerkson.ser
+import com.fasterxml.jackson.databind.JsonSerializer
+import com.fasterxml.jackson.databind.SerializerProvider
+import com.fasterxml.jackson.core.JsonGenerator
+
+class TupleSerializer extends JsonSerializer[Product] {
+  def serialize(value: Product, json: JsonGenerator, provider: SerializerProvider) {
+    json.writeStartArray()
+    for (v <- value.productIterator.toList) {
+    	provider.defaultSerializeValue(v, json)
+    }
+    json.writeEndArray()
+  }
+}
+
+object TupleSerializer {
+  val allTupleClasses: List[Class[_ <: Product]] = List(
+      classOf[Tuple1[_]],
+      classOf[Tuple2[_,_]],
+      classOf[Tuple3[_,_,_]],
+      classOf[Tuple4[_,_,_,_]],
+      classOf[Tuple5[_,_,_,_,_]],
+      classOf[Tuple6[_,_,_,_,_,_]],
+      classOf[Tuple7[_,_,_,_,_,_,_]],
+      classOf[Tuple8[_,_,_,_,_,_,_,_]],
+      classOf[Tuple9[_,_,_,_,_,_,_,_,_]],
+      classOf[Tuple10[_,_,_,_,_,_,_,_,_,_]],
+      classOf[Tuple11[_,_,_,_,_,_,_,_,_,_,_]],
+      classOf[Tuple12[_,_,_,_,_,_,_,_,_,_,_,_]],
+      classOf[Tuple13[_,_,_,_,_,_,_,_,_,_,_,_,_]],
+      classOf[Tuple14[_,_,_,_,_,_,_,_,_,_,_,_,_,_]],
+      classOf[Tuple15[_,_,_,_,_,_,_,_,_,_,_,_,_,_,_]],
+      classOf[Tuple16[_,_,_,_,_,_,_,_,_,_,_,_,_,_,_,_]],
+      classOf[Tuple17[_,_,_,_,_,_,_,_,_,_,_,_,_,_,_,_,_]],
+      classOf[Tuple18[_,_,_,_,_,_,_,_,_,_,_,_,_,_,_,_,_,_]],
+      classOf[Tuple19[_,_,_,_,_,_,_,_,_,_,_,_,_,_,_,_,_,_,_]],
+      classOf[Tuple20[_,_,_,_,_,_,_,_,_,_,_,_,_,_,_,_,_,_,_,_]],
+      classOf[Tuple21[_,_,_,_,_,_,_,_,_,_,_,_,_,_,_,_,_,_,_,_,_]],
+      classOf[Tuple22[_,_,_,_,_,_,_,_,_,_,_,_,_,_,_,_,_,_,_,_,_,_]]
+//      classOf[Tuple23[_,_,_,_,_,_,_,_,_,_,_,_,_,_,_,_,_,_,_,_,_,_,_]],
+  )
+}

src/test/scala/com/codahale/jerkson/tests/TupleSerializationSpec.scala

@@ -0,0 +1,52 @@
+package com.codahale.jerkson.tests
+
+import org.junit.Test
+import com.codahale.jerkson.Json
+import com.codahale.jerkson.ParsingException
+import com.codahale.simplespec.Spec
+
+class TupleSerializationSpec extends Spec {
+  class `Serialization` {
+    @Test def serializedAsArray() = {
+      Json.generate((1, "two", 3.0)).must(be("[1,\"two\",3.0]"))
+    }
+
+    @Test def serializedAsArrayWithUniformType() = {
+      Json.generate((1, 2, 3)).must(be("[1,2,3]"))
+    }
+  }
+
+  class `Parsing from arrays` {
+    @Test def parsedAsArrayWithAllIntegers() = {
+      Json.parse[(Int, Int, Int)]("[1, 2, 3]").must(be((1, 2, 3)))
+    }
+
+    @Test def parsedAsArray() = {
+      Json.parse[(Int, String, Double)]("[1, \"two\", 3.0]").must(be((1, "two", 3.0)))
+    }
+  }
+
+  class `Expected parsing failures` {
+    @Test(expected = classOf[ParsingException])
+    def errorWhenTooFewFieldsForTuple() = {
+      Json.parse[(Int, Int)]("[1]")
+    }
+
+    @Test(expected = classOf[ParsingException])
+    def errorWhenTooManyFieldsForTuple() = {
+      Json.parse[(Int)]("[1,2]")
+    }
+  }
+
+  class `Parses up to largest defined tuple` {
+    @Test def longestTupleLengthIsParsedWithAllIntegers() = {
+      val numbers  = 1 to 22
+      val str = "[" + numbers.mkString(",") + "]"
+
+      val t = (1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22)
+
+      Json.parse[(Int, Int, Int, Int, Int, Int, Int, Int, Int, Int, Int, Int, Int, Int, Int, Int, Int, Int, Int, Int, Int, Int)](str).must(
+          be(t))
+    }
+  }
+}