Restore java configuration for 'benchmarks' (#2027)

* Restore java configuration for 'benchmarks'
* Apply 'jmh' plugin after java configuration
* Specify java.util.concurrent imports after migration to Java 11
* Remove duplicated dependency
* Use release version of 'jmh' plugin. '0.5.0-rc-2' -> '0.5.0'

benchmarks/build.gradle.kts

@@ -2,24 +2,31 @@
  * Copyright 2016-2020 JetBrains s.r.o. Use of this source code is governed by the Apache 2.0 license.
  */
 
-import org.jetbrains.kotlin.gradle.tasks.KotlinCompile
+import me.champeau.gradle.*
+import org.jetbrains.kotlin.gradle.tasks.*
 
 plugins {
     id("net.ltgt.apt")
     id("com.github.johnrengelman.shadow")
-    id("me.champeau.gradle.jmh")
+    id("me.champeau.gradle.jmh") apply false
 }
 
 repositories {
     maven("https://repo.typesafe.com/typesafe/releases/")
 }
 
-tasks.withType<KotlinCompile>().configureEach {
-    kotlinOptions.jvmTarget = "1.8"
+java {
+    sourceCompatibility = JavaVersion.VERSION_1_8
+    targetCompatibility = JavaVersion.VERSION_1_8
 }
 
-tasks.compileJmhKotlin {
-    kotlinOptions.freeCompilerArgs += "-Xjvm-default=enable"
+apply(plugin="me.champeau.gradle.jmh")
+
+tasks.named<KotlinCompile>("compileJmhKotlin") {
+    kotlinOptions {
+        jvmTarget = "1.8"
+        freeCompilerArgs += "-Xjvm-default=enable"
+    }
 }
 
 /*
@@ -39,20 +46,20 @@ val removeRedundantFiles = tasks.register<Delete>("removeRedundantFiles") {
     delete("$buildDir/classes/kotlin/jmh/benchmarks/flow/scrabble/FlowPlaysScrabbleOpt\$play\$histoOfLetters\$1\$\$special\$\$inlined\$fold\$1\$1.class")
     delete("$buildDir/classes/kotlin/jmh/benchmarks/flow/scrabble/FlowPlaysScrabbleBase\$play\$buildHistoOnScore\$1\$\$special\$\$inlined\$filter\$1\$1.class")
     delete("$buildDir/classes/kotlin/jmh/benchmarks/flow/scrabble/FlowPlaysScrabbleBase\$play\$histoOfLetters\$1\$\$special\$\$inlined\$fold\$1\$1.class")
-    delete("$buildDir/classes/kotlin/jmh/benchmarks/flow/scrabble//SaneFlowPlaysScrabble\$play\$buildHistoOnScore\$1\$\$special\$\$inlined\$filter\$1\$1.class")
+    delete("$buildDir/classes/kotlin/jmh/benchmarks/flow/scrabble/SaneFlowPlaysScrabble\$play\$buildHistoOnScore\$1\$\$special\$\$inlined\$filter\$1\$1.class")
 
     // Primes
     delete("$buildDir/classes/kotlin/jmh/benchmarks/flow/misc/Numbers\$\$special\$\$inlined\$filter\$1\$2\$1.class")
     delete("$buildDir/classes/kotlin/jmh/benchmarks/flow/misc/Numbers\$\$special\$\$inlined\$filter\$1\$1.class")
 }
 
-tasks.jmhRunBytecodeGenerator {
+tasks.named("jmhRunBytecodeGenerator") {
     dependsOn(removeRedundantFiles)
 }
 
 // It is better to use the following to run benchmarks, otherwise you may get unexpected errors:
 // ./gradlew --no-daemon cleanJmhJar jmh -Pjmh="MyBenchmark"
-jmh {
+extensions.configure<JMHPluginExtension>("jmh") {
     jmhVersion = "1.21"
     duplicateClassesStrategy = DuplicatesStrategy.INCLUDE
     failOnError = true
@@ -63,7 +70,7 @@ jmh {
 //    includeTests = false
 }
 
-tasks.jmhJar {
+tasks.named<Jar>("jmhJar") {
     baseName = "benchmarks"
     classifier = null
     version = null
@@ -76,10 +83,9 @@ dependencies {
     compile("io.reactivex.rxjava2:rxjava:2.1.9")
     compile("com.github.akarnokd:rxjava2-extensions:0.20.8")
 
-    compile("org.openjdk.jmh:jmh-core:1.21")
     compile("com.typesafe.akka:akka-actor_2.12:2.5.0")
     compile(project(":kotlinx-coroutines-core"))
 
     // add jmh dependency on main
-    jmhImplementation(sourceSets.main.get().runtimeClasspath)
+    "jmhImplementation"(sourceSets.main.get().runtimeClasspath)
 }

benchmarks/src/jmh/kotlin/benchmarks/flow/FlowFlattenMergeBenchmark.kt

@@ -8,7 +8,7 @@ import benchmarks.common.*
 import kotlinx.coroutines.*
 import kotlinx.coroutines.flow.*
 import org.openjdk.jmh.annotations.*
-import java.util.concurrent.*
+import java.util.concurrent.TimeUnit
 
 /**
  * Benchmark to measure performance of [kotlinx.coroutines.flow.FlowKt.flattenMerge].

benchmarks/src/jmh/kotlin/benchmarks/flow/NumbersBenchmark.kt

@@ -11,7 +11,8 @@ import io.reactivex.functions.*
 import kotlinx.coroutines.*
 import kotlinx.coroutines.flow.*
 import org.openjdk.jmh.annotations.*
-import java.util.concurrent.*
+import java.util.concurrent.TimeUnit
+import java.util.concurrent.Callable
 
 @Warmup(iterations = 7, time = 1, timeUnit = TimeUnit.SECONDS)
 @Measurement(iterations = 7, time = 1, timeUnit = TimeUnit.SECONDS)

benchmarks/src/jmh/kotlin/benchmarks/flow/TakeBenchmark.kt

@@ -7,7 +7,7 @@ package benchmarks.flow
 import kotlinx.coroutines.*
 import kotlinx.coroutines.flow.*
 import org.openjdk.jmh.annotations.*
-import java.util.concurrent.*
+import java.util.concurrent.TimeUnit
 import java.util.concurrent.CancellationException
 import kotlin.coroutines.*
 import kotlin.coroutines.intrinsics.*

benchmarks/src/jmh/kotlin/benchmarks/flow/scrabble/FlowPlaysScrabbleBase.kt

@@ -9,7 +9,7 @@ import kotlinx.coroutines.flow.*
 import org.openjdk.jmh.annotations.*
 import java.lang.Long.max
 import java.util.*
-import java.util.concurrent.*
+import java.util.concurrent.TimeUnit
 import kotlin.math.*
 
 @Warmup(iterations = 7, time = 1, timeUnit = TimeUnit.SECONDS)

benchmarks/src/jmh/kotlin/benchmarks/flow/scrabble/SaneFlowPlaysScrabble.kt

@@ -9,7 +9,7 @@ import kotlinx.coroutines.flow.*
 import org.openjdk.jmh.annotations.*
 import java.lang.Long.*
 import java.util.*
-import java.util.concurrent.*
+import java.util.concurrent.TimeUnit
 
 @Warmup(iterations = 7, time = 1, timeUnit = TimeUnit.SECONDS)
 @Measurement(iterations = 7, time = 1, timeUnit = TimeUnit.SECONDS)

settings.gradle

@@ -8,7 +8,7 @@ pluginManagement {
 
         // JMH
         id "net.ltgt.apt" version "0.21"
-        id "me.champeau.gradle.jmh" version "0.5.0-rc-2"
+        id "me.champeau.gradle.jmh" version "0.5.0"
     }
 }