refactor: Simplify chat memory advisor hierarchy and remove deprecated API

Remove deprecated method in ChatMemory and refactor chat memory advisor classes

- Refactored AbstractChatMemoryAdvisor to inherit from BaseAdvisor, leveraging its default implementations for adviseCall and adviseStream methods
- Updated MessageChatMemoryAdvisor, PromptChatMemoryAdvisor, and VectorStoreChatMemoryAdvisor to directly implement their own before/after methods
- Removed deprecated ChatMemory.get(String conversationId, int lastN) method in favor of using MessageWindowChatMemory
- Fixed a bug in PromptChatMemoryAdvisor where it was only storing the last user message from a prompt with multiple messages
- Enhanced logging in memory advisors to aid in debugging
- Added comprehensive tests for advisor implementations:
  - Unit tests for MessageChatMemoryAdvisor and PromptChatMemoryAdvisor to check builder behavior
  - Integration tests for VectorStoreChatMemoryAdvisor with semantic memory retrieval

Signed-off-by: Mark Pollack <[email protected]>

Author: markpollack

advisors/spring-ai-advisors-vector-store/src/main/java/org/springframework/ai/chat/client/advisor/vectorstore/VectorStoreChatMemoryAdvisor.java

@@ -20,24 +20,17 @@
 import java.util.HashMap;
 import java.util.List;
 import java.util.Map;
-import java.util.stream.Collectors;
 
-import reactor.core.publisher.Flux;
-
-import org.springframework.ai.chat.client.advisor.AbstractChatMemoryAdvisor;
 import org.springframework.ai.chat.client.ChatClientRequest;
 import org.springframework.ai.chat.client.ChatClientResponse;
-import org.springframework.ai.chat.client.advisor.api.CallAdvisorChain;
-import org.springframework.ai.chat.client.advisor.api.StreamAdvisorChain;
+import org.springframework.ai.chat.client.advisor.AbstractChatMemoryAdvisor;
+import org.springframework.ai.chat.client.advisor.api.AdvisorChain;
 import org.springframework.ai.chat.messages.AssistantMessage;
 import org.springframework.ai.chat.messages.Message;
 import org.springframework.ai.chat.messages.MessageType;
-import org.springframework.ai.chat.messages.SystemMessage;
 import org.springframework.ai.chat.messages.UserMessage;
-import org.springframework.ai.chat.model.MessageAggregator;
 import org.springframework.ai.chat.prompt.PromptTemplate;
 import org.springframework.ai.document.Document;
-import org.springframework.ai.vectorstore.SearchRequest;
 import org.springframework.ai.vectorstore.VectorStore;
 
 /**
@@ -48,14 +41,22 @@
  * @author Christian Tzolov
  * @author Thomas Vitale
  * @author Oganes Bozoyan
+ * @author Mark Pollack
  * @since 1.0.0
  */
 public class VectorStoreChatMemoryAdvisor extends AbstractChatMemoryAdvisor<VectorStore> {
 
+	public static final String CHAT_MEMORY_RETRIEVE_SIZE_KEY = "chat_memory_response_size";
+
 	private static final String DOCUMENT_METADATA_CONVERSATION_ID = "conversationId";
 
 	private static final String DOCUMENT_METADATA_MESSAGE_TYPE = "messageType";
 
+	/**
+	 * The default chat memory retrieve size to use when no retrieve size is provided.
+	 */
+	public static final int DEFAULT_CHAT_MEMORY_RESPONSE_SIZE = 100;
+
 	private static final PromptTemplate DEFAULT_SYSTEM_PROMPT_TEMPLATE = new PromptTemplate("""
 			{instructions}
 
@@ -69,71 +70,64 @@ public class VectorStoreChatMemoryAdvisor extends AbstractChatMemoryAdvisor<Vect
 
 	private final PromptTemplate systemPromptTemplate;
 
-	private VectorStoreChatMemoryAdvisor(VectorStore vectorStore, String defaultConversationId,
-			int chatHistoryWindowSize, boolean protectFromBlocking, PromptTemplate systemPromptTemplate, int order) {
-		super(vectorStore, defaultConversationId, chatHistoryWindowSize, protectFromBlocking, order);
+	protected final int defaultChatMemoryRetrieveSize;
+
+	public VectorStoreChatMemoryAdvisor(VectorStore chatMemory, String defaultConversationId,
+			int defaultChatMemoryRetrieveSize, boolean protectFromBlocking, PromptTemplate systemPromptTemplate,
+			int order) {
+		super(chatMemory, defaultConversationId, protectFromBlocking, order);
 		this.systemPromptTemplate = systemPromptTemplate;
+		this.defaultChatMemoryRetrieveSize = defaultChatMemoryRetrieveSize;
 	}
 
 	public static Builder builder(VectorStore chatMemory) {
 		return new Builder(chatMemory);
 	}
 
 	@Override
-	public ChatClientResponse adviseCall(ChatClientRequest chatClientRequest, CallAdvisorChain callAdvisorChain) {
-		chatClientRequest = this.before(chatClientRequest);
-
-		ChatClientResponse chatClientResponse = callAdvisorChain.nextCall(chatClientRequest);
-
-		this.after(chatClientResponse);
-
-		return chatClientResponse;
-	}
-
-	@Override
-	public Flux<ChatClientResponse> adviseStream(ChatClientRequest chatClientRequest,
-			StreamAdvisorChain streamAdvisorChain) {
-		Flux<ChatClientResponse> chatClientResponses = this.doNextWithProtectFromBlockingBefore(chatClientRequest,
-				streamAdvisorChain, this::before);
-
-		return new MessageAggregator().aggregateChatClientResponse(chatClientResponses, this::after);
-	}
-
-	private ChatClientRequest before(ChatClientRequest chatClientRequest) {
-		String conversationId = this.doGetConversationId(chatClientRequest.context());
-		int chatMemoryRetrieveSize = this.doGetChatMemoryRetrieveSize(chatClientRequest.context());
-
-		// 1. Retrieve the chat memory for the current conversation.
-		var searchRequest = SearchRequest.builder()
-			.query(chatClientRequest.prompt().getUserMessage().getText())
-			.topK(chatMemoryRetrieveSize)
-			.filterExpression(DOCUMENT_METADATA_CONVERSATION_ID + "=='" + conversationId + "'")
+	public ChatClientRequest before(ChatClientRequest request, AdvisorChain advisorChain) {
+		String conversationId = doGetConversationId(request.context());
+		String query = request.prompt().getUserMessage() != null ? request.prompt().getUserMessage().getText() : "";
+		int topK = doGetChatMemoryRetrieveSize(request.context());
+		String filter = DOCUMENT_METADATA_CONVERSATION_ID + "=='" + conversationId + "'";
+		var searchRequest = org.springframework.ai.vectorstore.SearchRequest.builder()
+			.query(query)
+			.topK(topK)
+			.filterExpression(filter)
 			.build();
+		java.util.List<org.springframework.ai.document.Document> documents = this.getChatMemoryStore()
+			.similaritySearch(searchRequest);
 
-		List<Document> documents = this.getChatMemoryStore().similaritySearch(searchRequest);
-
-		// 2. Processed memory messages as a string.
 		String longTermMemory = documents == null ? ""
-				: documents.stream().map(Document::getText).collect(Collectors.joining(System.lineSeparator()));
+				: documents.stream()
+					.map(org.springframework.ai.document.Document::getText)
+					.collect(java.util.stream.Collectors.joining(System.lineSeparator()));
 
-		// 2. Augment the system message.
-		SystemMessage systemMessage = chatClientRequest.prompt().getSystemMessage();
+		org.springframework.ai.chat.messages.SystemMessage systemMessage = request.prompt().getSystemMessage();
 		String augmentedSystemText = this.systemPromptTemplate
-			.render(Map.of("instructions", systemMessage.getText(), "long_term_memory", longTermMemory));
+			.render(java.util.Map.of("instructions", systemMessage.getText(), "long_term_memory", longTermMemory));
 
-		// 3. Create a new request with the augmented system message.
-		ChatClientRequest processedChatClientRequest = chatClientRequest.mutate()
-			.prompt(chatClientRequest.prompt().augmentSystemMessage(augmentedSystemText))
+		ChatClientRequest processedChatClientRequest = request.mutate()
+			.prompt(request.prompt().augmentSystemMessage(augmentedSystemText))
 			.build();
 
-		// 4. Add the new user message to the conversation memory.
-		UserMessage userMessage = processedChatClientRequest.prompt().getUserMessage();
-		this.getChatMemoryStore().write(toDocuments(List.of(userMessage), conversationId));
+		org.springframework.ai.chat.messages.UserMessage userMessage = processedChatClientRequest.prompt()
+			.getUserMessage();
+		if (userMessage != null) {
+			this.getChatMemoryStore().write(toDocuments(java.util.List.of(userMessage), conversationId));
+		}
 
 		return processedChatClientRequest;
 	}
 
-	private void after(ChatClientResponse chatClientResponse) {
+	protected int doGetChatMemoryRetrieveSize(Map<String, Object> context) {
+		return context.containsKey(CHAT_MEMORY_RETRIEVE_SIZE_KEY)
+				? Integer.parseInt(context.get(CHAT_MEMORY_RETRIEVE_SIZE_KEY).toString())
+				: this.defaultChatMemoryRetrieveSize;
+	}
+
+	@Override
+	public ChatClientResponse after(ChatClientResponse chatClientResponse, AdvisorChain advisorChain) {
 		List<Message> assistantMessages = new ArrayList<>();
 		if (chatClientResponse.chatResponse() != null) {
 			assistantMessages = chatClientResponse.chatResponse()
@@ -144,6 +138,7 @@ private void after(ChatClientResponse chatClientResponse) {
 		}
 		this.getChatMemoryStore()
 			.write(toDocuments(assistantMessages, this.doGetConversationId(chatClientResponse.context())));
+		return chatClientResponse;
 	}
 
 	private List<Document> toDocuments(List<Message> messages, String conversationId) {
@@ -173,22 +168,56 @@ else if (message instanceof AssistantMessage assistantMessage) {
 		return docs;
 	}
 
-	public static class Builder extends AbstractChatMemoryAdvisor.AbstractBuilder<VectorStore> {
+	/**
+	 * Builder for VectorStoreChatMemoryAdvisor.
+	 */
+	public static class Builder extends AbstractChatMemoryAdvisor.AbstractBuilder<VectorStore, Builder> {
 
 		private PromptTemplate systemPromptTemplate = DEFAULT_SYSTEM_PROMPT_TEMPLATE;
 
-		protected Builder(VectorStore chatMemory) {
-			super(chatMemory);
+		private Integer chatMemoryRetrieveSize = DEFAULT_CHAT_MEMORY_RESPONSE_SIZE;
+
+		/**
+		 * Creates a new builder instance.
+		 * @param vectorStore the vector store to use
+		 */
+		protected Builder(VectorStore vectorStore) {
+			super(vectorStore);
 		}
 
-		public Builder systemTextAdvise(String systemTextAdvise) {
-			this.systemPromptTemplate = new PromptTemplate(systemTextAdvise);
+		@Override
+		protected Builder self() {
 			return this;
 		}
 
+		/**
+		 * Set the system prompt template.
+		 * @param systemPromptTemplate the system prompt template
+		 * @return this builder
+		 */
 		public Builder systemPromptTemplate(PromptTemplate systemPromptTemplate) {
 			this.systemPromptTemplate = systemPromptTemplate;
-			return this;
+			return self();
+		}
+
+		/**
+		 * Set the system prompt template using a text template.
+		 * @param systemTextAdvise the system prompt text template
+		 * @return this builder
+		 */
+		public Builder systemTextAdvise(String systemTextAdvise) {
+			this.systemPromptTemplate = new PromptTemplate(systemTextAdvise);
+			return self();
+		}
+
+		/**
+		 * Set the chat memory retrieve size.
+		 * @param chatMemoryRetrieveSize the chat memory retrieve size
+		 * @return this builder
+		 */
+		public Builder chatMemoryRetrieveSize(int chatMemoryRetrieveSize) {
+			this.chatMemoryRetrieveSize = chatMemoryRetrieveSize;
+			return self();
 		}
 
 		@Override