fix: Java ProducerPushDestination transformation and interceptor did …

…not work as expected

akka-projection-grpc-tests/src/test/scala/akka/projection/grpc/consumer/javadsl/EventProducerPushDestinationSpec.scala

@@ -0,0 +1,45 @@
+/*
+ * Copyright (C) 2009-2023 Lightbend Inc. <https://www.lightbend.com>
+ */
+package akka.projection.grpc.consumer.javadsl
+
+import akka.Done
+import akka.actor.testkit.typed.scaladsl.ScalaTestWithActorTestKit
+import akka.grpc.scaladsl.MetadataBuilder
+import org.scalatest.wordspec.AnyWordSpecLike
+
+import java.util.Collections
+import java.util.concurrent.CompletableFuture
+import scala.annotation.nowarn
+
+class EventProducerPushDestinationSpec extends ScalaTestWithActorTestKit with AnyWordSpecLike {
+
+  "The Java DSL EventProducerPushDestination" should {
+
+    "correctly map the transformationForOrigin to accept Scala GRPC metadata" in {
+      @nowarn("msg=never used")
+      val epsd = EventProducerPushDestination
+        .create("origin-id", Collections.emptyList(), system)
+        .withTransformationForOrigin((originId, metadata) => Transformation.identity)
+      val scalaEpsd = epsd.asScala
+
+      val transformation = scalaEpsd.transformationForOrigin("someOrigin", MetadataBuilder.empty)
+
+      transformation should be(Transformation.identity.delegate)
+    }
+
+    "correctly map the interceptor to accept Scala GRPC metadata" in {
+      @nowarn("msg=never used")
+      val epsd = EventProducerPushDestination
+        .create("origin-id", Collections.emptyList(), system)
+        .withInterceptor((originId, metadata) => CompletableFuture.completedFuture(Done))
+      val scalaEpsd = epsd.asScala
+
+      val interceptResult = scalaEpsd.interceptor.get.intercept("someOrigin", MetadataBuilder.empty)
+
+      interceptResult.futureValue should be(Done)
+    }
+
+  }
+
+}

akka-projection-grpc/src/main/scala/akka/projection/grpc/consumer/javadsl/EventProducerPushDestination.scala

@@ -8,6 +8,7 @@ import akka.actor.typed.ActorSystem
 import akka.annotation.ApiMayChange
 import akka.annotation.InternalApi
 import akka.dispatch.ExecutionContexts
+import akka.grpc.internal.JavaMetadataImpl
 import akka.grpc.javadsl.Metadata
 import akka.http.javadsl.model.HttpRequest
 import akka.http.javadsl.model.HttpResponse
@@ -155,9 +156,9 @@ final class EventProducerPushDestination private (
     new scaladsl.EventProducerPushDestination(
       journalPluginId.asScala,
       acceptedStreamId,
-      (origin, meta) => transformationForOrigin.apply(origin, meta.asInstanceOf[akka.grpc.javadsl.Metadata]).delegate,
+      (origin, meta) => transformationForOrigin.apply(origin, new JavaMetadataImpl(meta)).delegate,
       interceptor.asScala.map(javaInterceptor =>
-        (streamId, meta) => javaInterceptor.intercept(streamId, meta.asInstanceOf[akka.grpc.javadsl.Metadata]).toScala),
+        (streamId, meta) => javaInterceptor.intercept(streamId, new JavaMetadataImpl(meta)).toScala),
       filters.asScala.toVector,
       protobufDescriptors.asScala.toVector,
       settings)