convert middleware jackson to kotlin

build.gradle

@@ -2,7 +2,7 @@ apply from: 'buildsystem/dependencies.gradle'
 
 // Top-level build file where you can add configuration options common to all sub-projects/modules.
 buildscript {
-    ext.kotlin_version = '1.2.41'
+    ext.kotlin_version = '1.2.51'
     repositories {
         mavenLocal()
         maven {
@@ -19,11 +19,11 @@ buildscript {
     }
 
     rootProject.ext.versions = [
-        kotlin: '1.2.21'
+        kotlin: '1.2.51'
     ]
 
     dependencies {
-        classpath 'com.android.tools.build:gradle:3.2.0-alpha16'
+        classpath 'com.android.tools.build:gradle:3.2.0-beta02'
         classpath 'com.google.gms:google-services:3.0.0'
         classpath 'com.getkeepsafe.dexcount:dexcount-gradle-plugin:0.5.6'
         classpath 'net.ltgt.gradle:gradle-errorprone-plugin:0.0.11'

buildsystem/dependencies.gradle

@@ -39,7 +39,7 @@ ext.versions = [
         okio                 : '1.13.0',
         gson                 : '2.8.1',
         moshi                : '1.5.0',
-        jackson              : '2.8.8',
+        jackson              : '2.9.6',
         guava                : '19.0',
         javapoet             : '1.8.0',
         immutables           : '2.2.1',
@@ -96,6 +96,7 @@ ext.libraries = [
         gson                    : "com.google.code.gson:gson:$versions.gson",
         moshi                   : "com.squareup.moshi:moshi:$versions.moshi",
         jacksonCore             : "com.fasterxml.jackson.core:jackson-core:$versions.jackson",
+        jacksonKotlin           : "com.fasterxml.jackson.module:jackson-module-kotlin:$versions.jackson",
         jacksonDatabind         : "com.fasterxml.jackson.core:jackson-databind:$versions.jackson",
         guava                   : "com.google.guava:guava:$versions.guava",
         javapoet                : "com.squareup:javapoet:$versions.javapoet",

middleware-jackson/build.gradle

@@ -1,3 +1,7 @@
+plugins {
+    id 'org.jetbrains.kotlin.jvm'
+}
+
 apply plugin: 'java'
 
 group = GROUP
@@ -8,20 +12,28 @@ dependencies {
     implementation project(path: ':filesystem')
     compileOnly libraries.jsr305
     implementation libraries.jacksonCore
+    implementation libraries.jacksonKotlin
     implementation libraries.jacksonDatabind
     implementation libraries.okio
     compileOnly libraries.javax
     testImplementation libraries.mockito
     testImplementation libraries.junit
-}
-
-buildscript {
-    tasks.withType(JavaCompile) {
-        sourceCompatibility = JavaVersion.VERSION_1_8
-        targetCompatibility = JavaVersion.VERSION_1_8
-    }
+    compile "org.jetbrains.kotlin:kotlin-stdlib-jdk8"
 }
 
 apply from: rootProject.file("gradle/maven-push.gradle")
 apply from: rootProject.file("gradle/checkstyle.gradle")
 apply from: rootProject.file("gradle/pmd.gradle")
+repositories {
+    mavenCentral()
+}
+compileKotlin {
+    kotlinOptions {
+        jvmTarget = "1.8"
+    }
+}
+compileTestKotlin {
+    kotlinOptions {
+        jvmTarget = "1.8"
+    }
+}

middleware-jackson/src/main/java/com/nytimes/android/external/store3/middleware/jackson/JacksonBufferedSourceAdapter.kt

@@ -0,0 +1,28 @@
+package com.nytimes.android.external.store3.middleware.jackson
+
+import com.fasterxml.jackson.core.JsonProcessingException
+import com.fasterxml.jackson.databind.ObjectMapper
+import com.nytimes.android.external.fs3.BufferedSourceAdapter
+
+import java.io.ByteArrayInputStream
+import javax.inject.Inject
+
+import io.reactivex.exceptions.Exceptions
+import okio.BufferedSource
+import okio.Okio
+
+/**
+ * An implementation of [BufferedSourceAdapter] that uses [ObjectMapper] to convert Java values to JSON.
+ */
+class JacksonBufferedSourceAdapter<Parsed> @Inject
+constructor(private val objectMapper: ObjectMapper) : BufferedSourceAdapter<Parsed> {
+
+    override fun toJson(value: Parsed): BufferedSource {
+        try {
+            return Okio.buffer(Okio.source(ByteArrayInputStream(objectMapper.writeValueAsBytes(value))))
+        } catch (e: JsonProcessingException) {
+            throw Exceptions.propagate(e)
+        }
+
+    }
+}