From 8fa0adda4ddf8abd0e7321eead4cd2f1c0f8785d Mon Sep 17 00:00:00 2001
From: Xia Zuojie <zuojie@alibaba-inc.com>
Date: Tue, 23 Mar 2021 15:42:06 +0800
Subject: [PATCH 1/2] Use Mono.empty() instead of a State with null value

---
 sdk/src/main/java/io/dapr/client/DaprClientGrpc.java | 9 ++++++---
 sdk/src/main/java/io/dapr/client/DaprClientHttp.java | 9 ++++++---
 2 files changed, 12 insertions(+), 6 deletions(-)

diff --git a/sdk/src/main/java/io/dapr/client/DaprClientGrpc.java b/sdk/src/main/java/io/dapr/client/DaprClientGrpc.java
index 92cb523f69..d9c9043101 100644
--- a/sdk/src/main/java/io/dapr/client/DaprClientGrpc.java
+++ b/sdk/src/main/java/io/dapr/client/DaprClientGrpc.java
@@ -283,7 +283,7 @@ public <T> Mono<State<T>> getState(GetStateRequest request, TypeRef<T> type) {
               this.<DaprProtos.GetStateResponse>createMono(
                   it -> intercept(context, asyncStub).getState(envelope, it)
               )
-      ).map(
+      ).flatMap(
           it -> {
             try {
               return buildStateKeyValue(it, key, options, type);
@@ -369,7 +369,7 @@ private <T> State<T> buildStateKeyValue(
     return new State<>(key, value, etag, item.getMetadataMap(), null);
   }
 
-  private <T> State<T> buildStateKeyValue(
+  private <T> Mono<State<T>> buildStateKeyValue(
       DaprProtos.GetStateResponse response,
       String requestedKey,
       StateOptions stateOptions,
@@ -377,11 +377,14 @@ private <T> State<T> buildStateKeyValue(
     ByteString payload = response.getData();
     byte[] data = payload == null ? null : payload.toByteArray();
     T value = stateSerializer.deserialize(data, type);
+    if (value == null) {
+      return Mono.empty();
+    }
     String etag = response.getEtag();
     if (etag.equals("")) {
       etag = null;
     }
-    return new State<>(requestedKey, value, etag, response.getMetadataMap(), stateOptions);
+    return Mono.just(new State<>(requestedKey, value, etag, response.getMetadataMap(), stateOptions));
   }
 
   /**
diff --git a/sdk/src/main/java/io/dapr/client/DaprClientHttp.java b/sdk/src/main/java/io/dapr/client/DaprClientHttp.java
index 76a8c6c058..3ba895c24f 100644
--- a/sdk/src/main/java/io/dapr/client/DaprClientHttp.java
+++ b/sdk/src/main/java/io/dapr/client/DaprClientHttp.java
@@ -350,7 +350,7 @@ public <T> Mono<State<T>> getState(GetStateRequest request, TypeRef<T> type) {
           .invokeApi(DaprHttp.HttpMethods.GET.name(), pathSegments, queryParams, null, context)
       ).flatMap(s -> {
         try {
-          return Mono.justOrEmpty(buildState(s, key, options, type));
+          return buildState(s, key, options, type);
         } catch (Exception ex) {
           return DaprException.wrapMono(ex);
         }
@@ -513,15 +513,18 @@ public Mono<Void> deleteState(DeleteStateRequest request) {
    * @return A State instance
    * @throws IOException If there's a issue deserializing the response.
    */
-  private <T> State<T> buildState(
+  private <T> Mono<State<T>> buildState(
       DaprHttp.Response response, String requestedKey, StateOptions stateOptions, TypeRef<T> type) throws IOException {
     // The state is in the body directly, so we use the state serializer here.
     T value = stateSerializer.deserialize(response.getBody(), type);
+    if (value == null) {
+      return Mono.empty();
+    }
     String etag = null;
     if (response.getHeaders() != null && response.getHeaders().containsKey("Etag")) {
       etag = response.getHeaders().get("Etag");
     }
-    return new State<>(requestedKey, value, etag, stateOptions);
+    return Mono.just(new State<>(requestedKey, value, etag, stateOptions));
   }
 
   /**

From db4e6d3b77d9fc274423060a8892cb9a9231dd6a Mon Sep 17 00:00:00 2001
From: Xia Zuojie <zuojie@alibaba-inc.com>
Date: Wed, 24 Mar 2021 11:29:40 +0800
Subject: [PATCH 2/2] change: only null and empty byte[] are considered empty

---
 sdk/src/main/java/io/dapr/client/DaprClientGrpc.java | 4 ++--
 sdk/src/main/java/io/dapr/client/DaprClientHttp.java | 4 ++--
 2 files changed, 4 insertions(+), 4 deletions(-)

diff --git a/sdk/src/main/java/io/dapr/client/DaprClientGrpc.java b/sdk/src/main/java/io/dapr/client/DaprClientGrpc.java
index d9c9043101..426856ff10 100644
--- a/sdk/src/main/java/io/dapr/client/DaprClientGrpc.java
+++ b/sdk/src/main/java/io/dapr/client/DaprClientGrpc.java
@@ -376,10 +376,10 @@ private <T> Mono<State<T>> buildStateKeyValue(
       TypeRef<T> type) throws IOException {
     ByteString payload = response.getData();
     byte[] data = payload == null ? null : payload.toByteArray();
-    T value = stateSerializer.deserialize(data, type);
-    if (value == null) {
+    if (data == null || data.length == 0) {
       return Mono.empty();
     }
+    T value = stateSerializer.deserialize(data, type);
     String etag = response.getEtag();
     if (etag.equals("")) {
       etag = null;
diff --git a/sdk/src/main/java/io/dapr/client/DaprClientHttp.java b/sdk/src/main/java/io/dapr/client/DaprClientHttp.java
index 3ba895c24f..11ca07e6a8 100644
--- a/sdk/src/main/java/io/dapr/client/DaprClientHttp.java
+++ b/sdk/src/main/java/io/dapr/client/DaprClientHttp.java
@@ -516,10 +516,10 @@ public Mono<Void> deleteState(DeleteStateRequest request) {
   private <T> Mono<State<T>> buildState(
       DaprHttp.Response response, String requestedKey, StateOptions stateOptions, TypeRef<T> type) throws IOException {
     // The state is in the body directly, so we use the state serializer here.
-    T value = stateSerializer.deserialize(response.getBody(), type);
-    if (value == null) {
+    if (response.getBody() == null || response.getBody().length == 0) {
       return Mono.empty();
     }
+    T value = stateSerializer.deserialize(response.getBody(), type);
     String etag = null;
     if (response.getHeaders() != null && response.getHeaders().containsKey("Etag")) {
       etag = response.getHeaders().get("Etag");