make ChatHistory thread safe

Author: David Grieve

aiservices/openai/src/main/java/com/microsoft/semantickernel/aiservices/openai/chatcompletion/OpenAIChatCompletion.java

@@ -183,7 +183,7 @@ private static class ChatMessages {
 
         private final List<ChatRequestMessage> newMessages;
         private final List<ChatRequestMessage> allMessages;
-        private final List<OpenAIChatMessageContent> newChatMessageContent;
+        private final List<OpenAIChatMessageContent<?>> newChatMessageContent;
 
         public ChatMessages(List<ChatRequestMessage> allMessages) {
             this.allMessages = Collections.unmodifiableList(allMessages);
@@ -194,7 +194,7 @@ public ChatMessages(List<ChatRequestMessage> allMessages) {
         private ChatMessages(
             List<ChatRequestMessage> allMessages,
             List<ChatRequestMessage> newMessages,
-            List<OpenAIChatMessageContent> newChatMessageContent) {
+            List<OpenAIChatMessageContent<?>> newChatMessageContent) {
             this.allMessages = Collections.unmodifiableList(allMessages);
             this.newMessages = Collections.unmodifiableList(newMessages);
             this.newChatMessageContent = Collections.unmodifiableList(newChatMessageContent);
@@ -218,8 +218,8 @@ public ChatMessages add(ChatRequestMessage requestMessage) {
         }
 
         @CheckReturnValue
-        public ChatMessages addChatMessage(List<OpenAIChatMessageContent> chatMessageContent) {
-            ArrayList<OpenAIChatMessageContent> tmpChatMessageContent = new ArrayList<>(
+        public ChatMessages addChatMessage(List<OpenAIChatMessageContent<?>> chatMessageContent) {
+            ArrayList<OpenAIChatMessageContent<?>> tmpChatMessageContent = new ArrayList<>(
                 newChatMessageContent);
             tmpChatMessageContent.addAll(chatMessageContent);
 
@@ -580,7 +580,7 @@ private OpenAIFunctionToolCall extractOpenAIFunctionToolCall(
             arguments);
     }
 
-    private Mono<List<OpenAIChatMessageContent>> getChatMessageContentsAsync(
+    private Mono<List<OpenAIChatMessageContent<?>>> getChatMessageContentsAsync(
         ChatCompletions completions) {
         FunctionResultMetadata<CompletionsUsage> completionMetadata = FunctionResultMetadata.build(
             completions.getId(),
@@ -594,22 +594,27 @@ private Mono<List<OpenAIChatMessageContent>> getChatMessageContentsAsync(
             .filter(Objects::nonNull)
             .collect(Collectors.toList());
 
-        return Flux.fromIterable(responseMessages)
-            .flatMap(response -> {
+        List<OpenAIChatMessageContent<?>> chatMessageContent = 
+            responseMessages
+            .stream()
+            .map(response -> {
                 try {
-                    return Mono.just(new OpenAIChatMessageContent(
+                    return new OpenAIChatMessageContent<>(
                         AuthorRole.ASSISTANT,
                         response.getContent(),
                         this.getModelId(),
                         null,
                         null,
                         completionMetadata,
-                        formOpenAiToolCalls(response)));
+                        formOpenAiToolCalls(response));
                 } catch (Exception e) {
-                    return Mono.error(e);
+                    return null;
                 }
             })
-            .collectList();
+            .filter(Objects::nonNull)
+            .collect(Collectors.toList());
+
+        return Mono.just(chatMessageContent);
     }
 
     private List<ChatMessageContent<?>> toOpenAIChatMessageContent(

aiservices/openai/src/main/java/com/microsoft/semantickernel/aiservices/openai/chatcompletion/OpenAIChatMessageContent.java

@@ -36,7 +36,7 @@ public OpenAIChatMessageContent(
         @Nullable String modelId,
         @Nullable T innerContent,
         @Nullable Charset encoding,
-        @Nullable FunctionResultMetadata metadata,
+        @Nullable FunctionResultMetadata<?> metadata,
         @Nullable List<OpenAIFunctionToolCall> toolCall) {
         super(authorRole, content, modelId, innerContent, encoding, metadata);
 

semantickernel-api/src/main/java/com/microsoft/semantickernel/services/chatcompletion/ChatHistory.java

@@ -5,11 +5,13 @@
 import com.microsoft.semantickernel.services.chatcompletion.message.ChatMessageTextContent;
 import java.nio.charset.Charset;
 import java.util.ArrayList;
+import java.util.Collection;
 import java.util.Collections;
 import java.util.Iterator;
 import java.util.List;
 import java.util.Optional;
 import java.util.Spliterator;
+import java.util.concurrent.ConcurrentLinkedQueue;
 import java.util.function.Consumer;
 import javax.annotation.Nullable;
 
@@ -18,7 +20,7 @@
  */
 public class ChatHistory implements Iterable<ChatMessageContent<?>> {
 
-    private final List<ChatMessageContent<?>> chatMessageContents;
+    private final Collection<ChatMessageContent<?>> chatMessageContents;
 
     /**
      * The default constructor
@@ -33,7 +35,7 @@ public ChatHistory() {
      * @param instructions The instructions to add to the chat history
      */
     public ChatHistory(@Nullable String instructions) {
-        this.chatMessageContents = new ArrayList<>();
+        this.chatMessageContents = new ConcurrentLinkedQueue<>();
         if (instructions != null) {
             this.chatMessageContents.add(
                 ChatMessageTextContent.systemMessage(instructions));
@@ -45,8 +47,8 @@ public ChatHistory(@Nullable String instructions) {
      *
      * @param chatMessageContents The chat message contents to add to the chat history
      */
-    public ChatHistory(List<? extends ChatMessageContent> chatMessageContents) {
-        this.chatMessageContents = new ArrayList(chatMessageContents);
+    public ChatHistory(List<? extends ChatMessageContent<?>> chatMessageContents) {
+        this.chatMessageContents = new ConcurrentLinkedQueue<>(chatMessageContents);
     }
 
     /**
@@ -55,7 +57,7 @@ public ChatHistory(List<? extends ChatMessageContent> chatMessageContents) {
      * @return List of messages in the chat
      */
     public List<ChatMessageContent<?>> getMessages() {
-        return Collections.unmodifiableList(chatMessageContents);
+        return Collections.unmodifiableList(new ArrayList<>(chatMessageContents));
     }
 
     /**
@@ -67,7 +69,7 @@ public Optional<ChatMessageContent<?>> getLastMessage() {
         if (chatMessageContents.isEmpty()) {
             return Optional.empty();
         }
-        return Optional.of(chatMessageContents.get(chatMessageContents.size() - 1));
+        return Optional.of(((ConcurrentLinkedQueue<ChatMessageContent<?>>)chatMessageContents).peek());
     }
 
     /**
@@ -114,7 +116,7 @@ public Spliterator<ChatMessageContent<?>> spliterator() {
      * @param metadata   The metadata of the message
      */
     public void addMessage(AuthorRole authorRole, String content, Charset encoding,
-        FunctionResultMetadata metadata) {
+        FunctionResultMetadata<?> metadata) {
         chatMessageContents.add(
             ChatMessageTextContent.builder()
                 .withAuthorRole(authorRole)