Added addSerializer and addDeserializer extensions to SimpleModule for registering KClasses

release-notes/CREDITS-2.x

@@ -50,3 +50,7 @@ Drew Stephens (dinomite@github)
 
 Mateusz Stefek (MateuszStefek@github)
 * Reported #321: Make MissingKotlinParameterException a descendant of MismatchedInputException
+
+John Flynn (Neuman968@github)
+* Contributed extension methods for SimpleModule to add serializer and deserializer extension functions for KClass #322
+    (2.12.x)

release-notes/VERSION-2.x

@@ -4,6 +4,12 @@ Project: jackson-module-kotlin
 === Releases ===
 ------------------------------------------------------------------------
 
+2.12.0 (not yet released)
+
+#322 Added extension methods to SimpleModule addSerializer and addDeserializer to support KClass arguments that
+    register the serializer/deserializer for both the java type and java class.
+-
+
 2.11.1 (not yet released)
 
 -

src/main/kotlin/com/fasterxml/jackson/module/kotlin/Extensions.kt

@@ -7,10 +7,14 @@ import com.fasterxml.jackson.databind.JsonMappingException
 import com.fasterxml.jackson.databind.MappingIterator
 import com.fasterxml.jackson.databind.ObjectMapper
 import com.fasterxml.jackson.databind.ObjectReader
+import com.fasterxml.jackson.databind.module.SimpleModule
+import com.fasterxml.jackson.databind.JsonDeserializer
+import com.fasterxml.jackson.databind.JsonSerializer
 import java.io.File
 import java.io.InputStream
 import java.io.Reader
 import java.net.URL
+import kotlin.reflect.KClass
 
 fun jacksonObjectMapper(): ObjectMapper = ObjectMapper().registerKotlinModule()
 fun ObjectMapper.registerKotlinModule(): ObjectMapper = this.registerModule(KotlinModule())
@@ -35,4 +39,14 @@ inline fun <reified T> ObjectReader.readValuesTyped(jp: JsonParser): Iterator<T>
 inline fun <reified T> ObjectReader.treeToValue(n: TreeNode): T? = treeToValue(n, T::class.java)
 
 internal fun JsonMappingException.wrapWithPath(refFrom: Any?, refFieldName: String) = JsonMappingException.wrapWithPath(this, refFrom, refFieldName)
-internal fun JsonMappingException.wrapWithPath(refFrom: Any?, index: Int) = JsonMappingException.wrapWithPath(this, refFrom, index)
+internal fun JsonMappingException.wrapWithPath(refFrom: Any?, index: Int) = JsonMappingException.wrapWithPath(this, refFrom, index)
+
+inline fun <reified T : Any> SimpleModule.addSerializer(kClass: KClass<T>, serializer: JsonSerializer<T>) = this.apply {
+    addSerializer(kClass.java, serializer)
+    addSerializer(kClass.javaObjectType, serializer)
+}
+
+inline fun <reified T : Any> SimpleModule.addDeserializer(kClass: KClass<T>, deserializer: JsonDeserializer<T>) = this.apply {
+    addDeserializer(kClass.java, deserializer)
+    addDeserializer(kClass.javaObjectType, deserializer)
+}

src/test/kotlin/com/fasterxml/jackson/module/kotlin/test/KClassSerializerDeserializerTest.kt

@@ -0,0 +1,65 @@
+package com.fasterxml.jackson.module.kotlin.test
+
+import com.fasterxml.jackson.core.JsonGenerator
+import com.fasterxml.jackson.core.JsonParser
+import com.fasterxml.jackson.databind.*
+import com.fasterxml.jackson.databind.module.SimpleModule
+import com.fasterxml.jackson.module.kotlin.addDeserializer
+import com.fasterxml.jackson.module.kotlin.addSerializer
+import com.fasterxml.jackson.module.kotlin.jacksonObjectMapper
+import com.fasterxml.jackson.module.kotlin.readValue
+import org.hamcrest.CoreMatchers.equalTo
+import org.hamcrest.MatcherAssert.assertThat
+import org.junit.Test
+import java.math.BigDecimal
+import java.math.RoundingMode
+
+class KClassSerializerDeserializerTest {
+
+    val objectMapper = jacksonObjectMapper()
+            .registerModule(SimpleModule()
+                    .addSerializer(Double::class, RoundingSerializer())
+                    .addDeserializer(Double::class, RoundingDeserializer()))
+
+
+    @Test
+    fun `test custom serializer expecting object serialized with rounding serializer applied`() {
+        val jsonString = objectMapper.writeValueAsString(TestDoubleData(nonNullVal = 1.5567, nullVal = 1.5678))
+        val testResult = objectMapper.readValue(jsonString, TestDoubleData::class.java)
+        assertThat(testResult.nonNullVal, equalTo(1.56))
+        assertThat(testResult.nullVal, equalTo(1.57))
+    }
+
+    @Test
+    fun `test custom deserializer expecting object deserialized with rounding deserializer applied`() {
+        val testResult = objectMapper.readValue<TestDoubleData>("""
+            {
+                "nonNullVal":1.5567,
+                "nullVal":1.5678
+            }
+        """.trimIndent())
+        assertThat(testResult.nonNullVal, equalTo(1.56))
+        assertThat(testResult.nullVal, equalTo(1.57))
+    }
+}
+
+data class TestDoubleData(
+        val nonNullVal: Double,
+        val nullVal: Double?
+)
+
+class RoundingSerializer : JsonSerializer<Double>() {
+    override fun serialize(value: Double?, gen: JsonGenerator?, serializers: SerializerProvider?) {
+        value?.let {
+            gen?.writeNumber(BigDecimal(it).setScale(2, RoundingMode.HALF_UP))
+        }
+    }
+}
+
+class RoundingDeserializer : JsonDeserializer<Double>() {
+    override fun deserialize(p: JsonParser?, ctxt: DeserializationContext?): Double? {
+        return BigDecimal(p?.valueAsString)
+                .setScale(2, RoundingMode.HALF_UP)
+                .toDouble()
+    }
+}