Support ActorMethod to change method's name.

examples/src/main/java/io/dapr/examples/actors/DemoActor.java

@@ -17,6 +17,7 @@ public interface DemoActor {
 
   void registerReminder();
 
+  @ActorMethod(name = "echo_message")
   String say(String something);
 
   void clock(String message);

examples/src/main/java/io/dapr/examples/actors/README.md

@@ -105,6 +105,8 @@ public class DemoActorImpl extends AbstractActor implements DemoActor, Remindabl
 An actor inherits from `AbstractActor` and implements the constructor to pass through `ActorRuntimeContext` and `ActorId`. By default, the actor's name will be the same as the class' name. Optionally, it can be annotated with `ActorType` and override the actor's name. The actor's methods can be synchronously or use [Project Reactor's Mono](https://projectreactor.io/docs/core/release/api/reactor/core/publisher/Mono.html) return type. Finally, state management is done via methods in `super.getActorStateManager()`. The `DemoActor` interface is used by the Actor runtime and also client. See how `DemoActor` interface can be annotated as Dapr Actor.
 
 ```java
+import io.dapr.actors.ActorMethod;
+
 /**
  * Example of implementation of an Actor.
  */
@@ -113,6 +115,7 @@ public interface DemoActor {
 
   void registerReminder();
 
+  @ActorMethod(name = "echo_message")
   String say(String something);
 
   void clock(String message);
@@ -123,7 +126,10 @@ public interface DemoActor {
 
 ```
 
-The `@ActorType` annotation indicates the Dapr Java SDK that this interface is an Actor Type, allowing a name for the type to be defined. Some methods can return a `Mono` object. In these cases, the `@ActorMethod` annotation is used to hint the Dapr Java SDK of the type encapsulated in the `Mono` object. You can read more about Java generic type erasure [here](https://docs.oracle.com/javase/tutorial/java/generics/erasure.html).  
+The `@ActorType` annotation indicates the Dapr Java SDK that this interface is an Actor Type, allowing a name for the type to be defined. 
+
+The `@ActorMethod` annotation can be applied to an interface method to specify configuration for that method. In this example, the `say` method, is renamed to `echo_message` - this can be used when invoking an actor method implemented in a different programming language (like C# or Python) and the method name does not match Java's naming conventions.
+Some methods can return a `Mono` object. In these cases, the `@ActorMethod` annotation is used to hint the Dapr Java SDK of the type encapsulated in the `Mono` object. You can read more about Java generic type erasure [here](https://docs.oracle.com/javase/tutorial/java/generics/erasure.html).  
 
 
 Now, execute the following script in order to run DemoActorService:

sdk-actors/src/main/java/io/dapr/actors/ActorMethod.java

@@ -21,5 +21,13 @@
    *
    * @return Actor's method return type.
    */
-  Class returns();
+  Class returns() default Undefined.class;
+
+  /**
+   * Actor's method name. This is optional and will override the method's default name for actor invocation.
+   *
+   * @return Actor's method name.
+   */
+  String name() default "";
+
 }

sdk-actors/src/main/java/io/dapr/actors/Undefined.java

@@ -0,0 +1,16 @@
+/*
+ * Copyright (c) Microsoft Corporation.
+ * Licensed under the MIT License.
+ */
+
+package io.dapr.actors;
+
+/**
+ * Internal class to represent the undefined value for an optional Class attribute.
+ */
+final class Undefined {
+
+  private Undefined() {
+  }
+
+}

sdk-actors/src/main/java/io/dapr/actors/client/ActorProxyImpl.java

@@ -21,6 +21,8 @@
  */
 class ActorProxyImpl implements ActorProxy, InvocationHandler {
 
+  private static final String UNDEFINED_CLASS_NAME = "io.dapr.actors.Undefined";
+
   /**
    * Actor's identifier for this Actor instance.
    */
@@ -136,29 +138,33 @@ public Object invoke(Object proxy, Method method, Object[] args) {
       throw new UnsupportedOperationException("Actor methods can only have zero or one arguments.");
     }
 
+    ActorMethod actorMethodAnnotation = method.getDeclaredAnnotation(ActorMethod.class);
+    String methodName = method.getName();
+    if ((actorMethodAnnotation != null) && !actorMethodAnnotation.name().isEmpty()) {
+      methodName = actorMethodAnnotation.name();
+    }
+
     if (method.getParameterCount() == 0) {
       if (method.getReturnType().equals(Mono.class)) {
-        ActorMethod actorMethodAnnotation = method.getDeclaredAnnotation(ActorMethod.class);
-        if (actorMethodAnnotation == null) {
-          return invokeMethod(method.getName());
+        if ((actorMethodAnnotation == null) || UNDEFINED_CLASS_NAME.equals(actorMethodAnnotation.returns().getName())) {
+          return invokeMethod(methodName);
         }
 
-        return invokeMethod(method.getName(), actorMethodAnnotation.returns());
+        return invokeMethod(methodName, actorMethodAnnotation.returns());
       }
 
-      return invokeMethod(method.getName(), method.getReturnType()).block();
+      return invokeMethod(methodName, method.getReturnType()).block();
     }
 
     if (method.getReturnType().equals(Mono.class)) {
-      ActorMethod actorMethodAnnotation = method.getDeclaredAnnotation(ActorMethod.class);
-      if (actorMethodAnnotation == null) {
-        return invokeMethod(method.getName(), args[0]);
+      if ((actorMethodAnnotation == null) || UNDEFINED_CLASS_NAME.equals(actorMethodAnnotation.returns().getName())) {
+        return invokeMethod(methodName, args[0]);
       }
 
-      return invokeMethod(method.getName(), args[0], actorMethodAnnotation.returns());
+      return invokeMethod(methodName, args[0], actorMethodAnnotation.returns());
     }
 
-    return invokeMethod(method.getName(), args[0], method.getReturnType()).block();
+    return invokeMethod(methodName, args[0], method.getReturnType()).block();
   }
 
   /**

sdk-actors/src/main/java/io/dapr/actors/runtime/ActorMethodInfoMap.java

@@ -5,6 +5,8 @@
 
 package io.dapr.actors.runtime;
 
+import io.dapr.actors.ActorMethod;
+
 import java.lang.reflect.Method;
 import java.util.Collection;
 import java.util.Collections;
@@ -35,7 +37,12 @@ class ActorMethodInfoMap {
         if (methodInfo.getParameterCount() <= 1) {
           // If Actor class uses overloading, then one will win.
           // Document this behavior, so users know how to write their code.
-          methods.put(methodInfo.getName(), methodInfo);
+          String methodName = methodInfo.getName();
+          ActorMethod actorMethodAnnotation = methodInfo.getAnnotation(ActorMethod.class);
+          if ((actorMethodAnnotation != null) && !actorMethodAnnotation.name().isEmpty()) {
+            methodName = actorMethodAnnotation.name();
+          }
+          methods.put(methodName, methodInfo);
         }
       }
     }

sdk-actors/src/test/java/io/dapr/actors/runtime/ActorNoStateTest.java

@@ -6,6 +6,7 @@
 package io.dapr.actors.runtime;
 
 import io.dapr.actors.ActorId;
+import io.dapr.actors.ActorMethod;
 import io.dapr.actors.ActorType;
 import io.dapr.actors.client.ActorProxy;
 import io.dapr.actors.client.ActorProxyForTestsImpl;
@@ -43,6 +44,8 @@ public interface MyActor {
     Mono<MyData> classInClassOut(MyData input);
     Mono<String> registerBadCallbackName();
     String registerTimerAutoName();
+    @ActorMethod(name = "DotNetMethodASync")
+    Mono<Void> dotNetMethod();
   }
 
   @ActorType(name = "MyActor")
@@ -108,6 +111,11 @@ public Mono<String> registerBadCallbackName() {
     public String registerTimerAutoName() {
       return super.registerActorTimer("", "anything", "state", Duration.ofSeconds(1), Duration.ofSeconds(1)).block();
     }
+
+    @Override
+    public Mono<Void> dotNetMethod() {
+      return Mono.empty();
+    }
   }
 
   static class MyData {
@@ -174,6 +182,12 @@ public void stringInVoidOutIntentionallyThrows() {
     actorProxy.invokeMethod("stringInVoidOutIntentionallyThrows", "hello world").block();
   }
 
+  @Test
+  public void testMethodNameChange() {
+    MyActor actor = createActorProxy(MyActor.class);
+    actor.dotNetMethod();
+  }
+
   @Test
   public void classInClassOut() {
     ActorProxy actorProxy = createActorProxy();

sdk-tests/src/test/java/io/dapr/it/actors/ActorMethodNameIT.java

@@ -0,0 +1,62 @@
+/*
+ * Copyright (c) Microsoft Corporation.
+ * Licensed under the MIT License.
+ */
+
+package io.dapr.it.actors;
+
+import io.dapr.actors.ActorId;
+import io.dapr.actors.client.ActorProxy;
+import io.dapr.actors.client.ActorProxyBuilder;
+import io.dapr.it.BaseIT;
+import io.dapr.it.actors.app.MyActor;
+import io.dapr.it.actors.app.MyActorService;
+import org.junit.Test;
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
+
+import static io.dapr.it.Retry.callWithRetry;
+import static org.junit.Assert.assertTrue;
+
+public class ActorMethodNameIT extends BaseIT {
+
+  private static Logger logger = LoggerFactory.getLogger(ActorMethodNameIT.class);
+
+  @Test
+  public void actorMethodNameChange() throws Exception {
+    // The call below will fail if service cannot start successfully.
+    startDaprApp(
+        ActorMethodNameIT.class.getSimpleName(),
+        MyActorService.SUCCESS_MESSAGE,
+        MyActorService.class,
+        true,
+        60000);
+
+    logger.debug("Creating proxy builder");
+    ActorProxyBuilder<MyActor> proxyBuilder = deferClose(new ActorProxyBuilder("MyActorTest", MyActor.class));
+    logger.debug("Creating actorId");
+    ActorId actorId1 = new ActorId("1");
+    logger.debug("Building proxy");
+    MyActor proxy = proxyBuilder.build(actorId1);
+
+    callWithRetry(() -> {
+      logger.debug("Invoking dotNetMethod from Proxy");
+      boolean response = proxy.dotNetMethod();
+      logger.debug("asserting true response: [" + response + "]");
+      assertTrue(response);
+    }, 60000);
+
+    logger.debug("Creating proxy builder 2");
+    ActorProxyBuilder<ActorProxy> proxyBuilder2 = deferClose(new ActorProxyBuilder("MyActorTest", ActorProxy.class));
+    logger.debug("Building proxy 2");
+    ActorProxy proxy2 = proxyBuilder2.build(actorId1);
+
+    callWithRetry(() -> {
+      logger.debug("Invoking DotNetMethodAsync from Proxy 2");
+      boolean response = proxy2.invokeMethod("DotNetMethodAsync", boolean.class).block();
+      logger.debug("asserting true response 2: [" + response + "]");
+      assertTrue(response);
+    }, 60000);
+
+  }
+}

sdk-tests/src/test/java/io/dapr/it/actors/app/MyActor.java

@@ -5,6 +5,8 @@
 
 package io.dapr.it.actors.app;
 
+import io.dapr.actors.ActorMethod;
+
 import java.util.ArrayList;
 import java.util.List;
 
@@ -26,4 +28,7 @@ public interface MyActor {
   ArrayList<String> getCallLog();
 
   String getIdentifier();
+
+  @ActorMethod(name = "DotNetMethodAsync")
+  boolean dotNetMethod();
 }

sdk-tests/src/test/java/io/dapr/it/actors/app/MyActorImpl.java

@@ -199,6 +199,11 @@ public String getIdentifier() {
     return System.getenv("DAPR_HTTP_PORT");
   }
 
+  @Override
+  public boolean dotNetMethod() {
+    return true;
+  }
+
   private void formatAndLog(boolean isEnter, String methodName) {
     Calendar utcNow = Calendar.getInstance(TimeZone.getTimeZone("GMT"));