use methodhandle

apache · Jan 17, 2024 · c0d7e15 · c0d7e15
1 parent 5bd8e4f
commit c0d7e15
Showing 1 changed file with 17 additions and 7 deletions.
diff --git a/actor/src/main/scala/org/apache/pekko/dispatch/ForkJoinExecutorConfigurator.scala b/actor/src/main/scala/org/apache/pekko/dispatch/ForkJoinExecutorConfigurator.scala
@@ -15,6 +15,7 @@ package org.apache.pekko.dispatch
 
 import com.typesafe.config.Config
 
+import java.lang.invoke.{ MethodHandle, MethodHandles, MethodType }
 import java.util.concurrent.{ ExecutorService, ForkJoinPool, ForkJoinTask, ThreadFactory }
 import scala.util.Try
 
@@ -93,17 +94,26 @@ class ForkJoinExecutorConfigurator(config: Config, prerequisites: DispatcherPrer
         parallelism: Int,
         asyncMode: Boolean) = this(threadFactory, parallelism, asyncMode, ForkJoinPoolConstants.MaxCap)
 
-    private lazy val pekkoJdk9ForkJoinPoolClassOpt: Option[Class[_]] =
+    private def pekkoJdk9ForkJoinPoolClassOpt: Option[Class[_]] =
       Try(Class.forName("org.apache.pekko.dispatch.PekkoJdk9ForkJoinPool")).toOption
 
+    private lazy val pekkoJdk9ForkJoinPoolHandleOpt: Option[MethodHandle] = {
+      pekkoJdk9ForkJoinPoolClassOpt.map { clz =>
+        val methodHandleLookup = MethodHandles.lookup()
+        val mt = MethodType.methodType(classOf[Unit], classOf[Int],
+          classOf[ForkJoinPool.ForkJoinWorkerThreadFactory],
+          classOf[Int], classOf[Thread.UncaughtExceptionHandler], classOf[Boolean])
+        methodHandleLookup.findConstructor(clz, mt)
+      }
+    }
+
     def this(threadFactory: ForkJoinPool.ForkJoinWorkerThreadFactory, parallelism: Int) =
       this(threadFactory, parallelism, asyncMode = true)
-    def createExecutorService: ExecutorService = pekkoJdk9ForkJoinPoolClassOpt match {
-      case Some(clz) =>
-        // there is only one constructor (Object conversion required by Scala 2.12)
-        clz.getConstructors.head.newInstance(parallelism.asInstanceOf[Object], threadFactory,
-          maxPoolSize.asInstanceOf[Object], MonitorableThreadFactory.doNothing,
-          asyncMode.asInstanceOf[Object]).asInstanceOf[ExecutorService]
+
+    def createExecutorService: ExecutorService = pekkoJdk9ForkJoinPoolHandleOpt match {
+      case Some(handle) =>
+        handle.invokeExact(parallelism, threadFactory, maxPoolSize,
+          MonitorableThreadFactory.doNothing, asyncMode).asInstanceOf[ExecutorService]
       case _ =>
         new PekkoForkJoinPool(parallelism, threadFactory, MonitorableThreadFactory.doNothing, asyncMode)
     }