From 4b3d32e64a286ccfae5f17160c5d75fc30a95cca Mon Sep 17 00:00:00 2001
From: Adriano Santos <sleipnir@bsd.com.br>
Date: Fri, 20 Oct 2023 12:16:22 -0300
Subject: [PATCH] Added Null guarantee

---
 lib/src/actors/actor.dart                 | 12 ++++++------
 lib/src/stateful_named_actor_handler.dart | 23 +++++++++++++++++------
 2 files changed, 23 insertions(+), 12 deletions(-)

diff --git a/lib/src/actors/actor.dart b/lib/src/actors/actor.dart
index 04ca4bc..a5a1dcd 100644
--- a/lib/src/actors/actor.dart
+++ b/lib/src/actors/actor.dart
@@ -20,24 +20,24 @@ class Context {
 }
 
 class Value {
-  late Object _state;
-  late Object _value;
+  Optional<Object> _state = Optional.empty();
+  Optional<Object> _value = Optional.empty();
 
-  Object get state {
+  Optional<Object> get state {
     return _state;
   }
 
-  Object get value {
+  Optional<Object> get value {
     return _value;
   }
 
   Value withReponse<R extends GeneratedMessage>(R response) {
-    _value = response;
+    _value = Optional.of(response);
     return this;
   }
 
   Value withState<S extends GeneratedMessage>(S newState) {
-    _state = newState;
+    _state = Optional.of(newState);
     return this;
   }
 }
diff --git a/lib/src/stateful_named_actor_handler.dart b/lib/src/stateful_named_actor_handler.dart
index 43f71ce..4b084ef 100644
--- a/lib/src/stateful_named_actor_handler.dart
+++ b/lib/src/stateful_named_actor_handler.dart
@@ -79,13 +79,24 @@ class StatefulNamedActorHandler implements ActorHandler {
         Value resultValue = result.value;
 
         spawn_protocol.Context updatedCtx = spawn_protocol.Context.create();
-        updatedCtx.state = Any.pack(resultValue.state as GeneratedMessage);
 
-        return spawn_protocol.ActorInvocationResponse.create()
-          ..actorName = invocation.actor.name
-          ..actorSystem = invocation.actor.system
-          ..updatedContext = updatedCtx
-          ..value = Any.pack(resultValue.value as GeneratedMessage);
+        if (resultValue.state.isPresent) {
+          updatedCtx.state =
+              Any.pack(resultValue.state.value as GeneratedMessage);
+        }
+
+        spawn_protocol.ActorInvocationResponse resp =
+            spawn_protocol.ActorInvocationResponse.create();
+
+        resp.actorName = invocation.actor.name;
+        resp.actorSystem = invocation.actor.system;
+        resp.updatedContext = updatedCtx;
+
+        if (resultValue.value.isPresent) {
+          resp.value = Any.pack(resultValue.value.value as GeneratedMessage);
+        }
+
+        return resp;
       }
     }