THRIFT-5548: add kotlin code gen
Client: kotlin
Patch: Jiayu Liu

This closes #2556
diff --git a/lib/kotlin/cross-test-server/build.gradle.kts b/lib/kotlin/cross-test-server/build.gradle.kts
new file mode 100644
index 0000000..6b20de1
--- /dev/null
+++ b/lib/kotlin/cross-test-server/build.gradle.kts
@@ -0,0 +1,82 @@
+/*
+ * Licensed to the Apache Software Foundation (ASF) under one
+ * or more contributor license agreements.  See the NOTICE file
+ * distributed with this work for additional information
+ * regarding copyright ownership.  The ASF licenses this file
+ * to you under the Apache License, Version 2.0 (the
+ * "License"); you may not use this file except in compliance
+ * with the License.  You may obtain a copy of the License at
+ *
+ *   http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing,
+ * software distributed under the License is distributed on an
+ * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+ * KIND, either express or implied.  See the License for the
+ * specific language governing permissions and limitations
+ * under the License.
+ */
+
+plugins {
+    kotlin("jvm") version "1.5.31"
+    id("com.ncorti.ktfmt.gradle") version "0.4.0"
+    java
+    application
+}
+
+repositories {
+    mavenCentral()
+}
+
+dependencies {
+    implementation(platform("org.jetbrains.kotlin:kotlin-bom"))
+    implementation("org.jetbrains.kotlin:kotlin-stdlib-jdk8")
+    // https://mvnrepository.com/artifact/org.jetbrains.kotlinx/kotlinx-coroutines-jdk8
+    implementation("org.jetbrains.kotlinx:kotlinx-coroutines-jdk8:1.6.1")
+    // https://mvnrepository.com/artifact/org.apache.thrift/libthrift
+    implementation("org.apache.thrift:libthrift:INCLUDED")
+    // https://mvnrepository.com/artifact/ch.qos.logback/logback-classic
+    implementation("ch.qos.logback:logback-classic:1.3.0-alpha14")
+    testImplementation("org.jetbrains.kotlin:kotlin-test")
+    testImplementation("org.jetbrains.kotlin:kotlin-test-junit")
+}
+
+tasks {
+    application {
+        applicationName = "TestServer"
+        mainClass.set("org.apache.thrift.test.TestServerKt")
+    }
+
+    ktfmt {
+        kotlinLangStyle()
+    }
+
+    task<Exec>("compileThrift") {
+        val thriftBin = if (hasProperty("thrift.compiler")) {
+            file(property("thrift.compiler"))
+        } else {
+            project.rootDir.resolve("../../compiler/cpp/thrift")
+        }
+        val outputDir = layout.buildDirectory.dir("generated-sources")
+        doFirst {
+            mkdir(outputDir)
+        }
+        commandLine = listOf(
+            thriftBin.absolutePath,
+            "-gen",
+            "kotlin",
+            "-out",
+            outputDir.get().toString(),
+            project.rootDir.resolve("../../test/ThriftTest.thrift").absolutePath
+        )
+        group = LifecycleBasePlugin.BUILD_GROUP
+    }
+
+    compileKotlin {
+        dependsOn("compileThrift")
+    }
+}
+
+sourceSets["main"].java {
+    srcDir(layout.buildDirectory.dir("generated-sources"))
+}