Refactoring of ChatClient to add fluent API and introduce Model as de…

…pendent object

* Rename the ModelClient class hierarchy into Model:
  - Rename ModelClient into Model. Update all code and doc references.
  - Rename ChatClient to ChatModel. Update all ChatClient suffixes and chatClient fields and variables in code and doc.
  - Rename EmbeddingClient into EmbeddingModel. Update the XxxEmbeddingClient class and variable suffixes and embeddingClient variables and fields in code and docs.
  - Rename ImageClient into ImageModel.
  - Rename SpeechClient into SpeechModel.
  - Rename TranscriptionClient into TranscriptionModel.
  - Update all javadocs and antora pages. Update the related diagrams.

* Create fluent API in ChatClient interface that now includes streaming support
* Add OpenAI FunctionCallbackWrapper2IT auto-config tests.
* Add ChatClientTest mockito testing.
* Add ChatModel#getDefaultOptions(), and remove @FunctionalInterface

* ChatModel enums extend the new ModelDescription interface.
* Implement fromOptions copy method in every ChatOptions implementation.
* Extend ChatClient to use the model default options if not provided explicitly.

* Update readme to provide guidance on how to adapt to breaking changes.

Co-authored-by: Christian Tzolov <ctzolov@vmware.com>
Co-authored-by: Mark Pollack <mpollack@vmware.com>

README.md

@@ -8,9 +8,147 @@ Let's make your `@Beans` intelligent!
 
 For further information go to our [Spring AI reference documentation](https://docs.spring.io/spring-ai/reference/).
 
-### Breaking changes
-(15.05.2024)
-On our march to release 1.0 M1 we have made several breaking changes.  Apologies, it is for the best!
+## Breaking changes
+
+On our march to release 1.0.0 M1 we have made several breaking changes.  Apologies, it is for the best!
+
+**(22.05.2024)**
+
+A major change was made that took the 'old' `ChatClient` and moved the functionality into `ChatModel`.  The 'new' `ChatClient` now takes an instance of `ChatModel`. This was done do support a fluent API for creating and executing prompts in a style similar to other client classes in the Spring ecosystem, such as `RestClient`, `WebClient`, and `JdbcClient`.  Refer to the [JavaDoc](https://docs.spring.io/spring-ai/docs/1.0.0-SNAPSHOT/api/) for more information on the Fluent API, proper reference documentation is coming shortly. 
+
+We renamed the 'old' `ModelClient` to `Model` and renamed implementing classes, for example `ImageClient` was renamed to `ImageModel`.  The `Model` implementation represent the portability layer that converts between the Spring AI API and the underlying AI Model API.
+
+### Adapting to the changes
+
+#### Approach 1
+
+Now, instead of getting an Autoconfigured `ChatClient` instance, you will get a `ChatModel` instance.  The `call` method signatures after renaming remain the same.
+To adapt your code should refactor you code to change use of the type `ChatClient` to `ChatModel` 
+Here is an example of existing code before the change
+
+```java
+@RestController
+public class OldSimpleAiController {
+
+	private final ChatClient chatClient;
+
+	@Autowired
+	public OldSimpleAiController(ChatClient chatClient) {
+		this.chatClient = chatClient;
+	}
+
+	@GetMapping("/ai/simple")
+	public Map<String, String> completion(@RequestParam(value = "message", defaultValue = "Tell me a joke") String message) {
+		return Map.of("generation", chatClient.call(message));
+	}
+}
+```
+
+Now after the changes this will be 
+
+```java
+@RestController
+public class SimpleAiController {
+
+	private final ChatModel chatModel;
+
+	@Autowired
+	public SimpleAiController(ChatModel chatModel) {
+		this.chatModel = chatModel;
+	}
+
+	@GetMapping("/ai/simple")
+	public Map<String, String> completion(@RequestParam(value = "message", defaultValue = "Tell me a joke") String message) {
+		return Map.of("generation", chatModel.call(message));
+	}
+}
+```
+
+NOTE: The renaming also applies to the classes
+* `StreamingChatClient` -> `StreamingChatModel`
+* `EmbeddingClient` -> `EmbeddingModel`
+* `ImageClient` -> `ImageModel`
+* `SpeechClient` -> `SpeechModel`
+* and similar for other `<XYZ>Client` classes
+
+#### Approach 2
+
+In this approach you will use the new fluent API available on the 'new' `ChatClient`
+
+Here is an example of existing code before the change
+
+```java
+@RestController
+public class OldSimpleAiController {
+
+	private final ChatClient chatClient;
+
+	@Autowired
+	public OldSimpleAiController(ChatClient chatClient) {
+		this.chatClient = chatClient;
+	}
+
+	@GetMapping("/ai/simple")
+	public Map<String, String> completion(@RequestParam(value = "message", defaultValue = "Tell me a joke") String message) {
+		return Map.of(
+                "generation",
+                chatClient.call(message)
+        );
+	}
+}
+```
+
+
+Now after the changes this will be
+
+```java
+@RestController
+public class SimpleAiController {
+
+	private final ChatClient chatClient;
+
+	@Autowired
+	public SimpleAiController(ChatClient chatClient) {
+		this.chatClient = chatClient;
+	}
+
+	@GetMapping("/ai/simple")
+	public Map<String, String> completion(@RequestParam(value = "message", defaultValue = "Tell me a joke") String message) {
+		return Map.of(
+                "generation", 
+                chatClient.prompt().user(message).call().content()
+        );
+	}
+}
+```
+
+and in your `@Configuration` class you need to define an `@Bean` as shown below
+
+```java
+@Configuration
+public class ApplicationConfiguration {
+
+  @Bean
+  ChatClient chatClient(ChatModel chatModel) {
+    return ChatClient.builder(chatModel).build();
+  }
+}
+```
+
+NOTE: The `ChatModel` instance is made available to you through autoconfiguration.
+
+#### Approach 3
+
+There is a tag in the GitHub repository called [v1.0.0-SNAPSHOT-before-chatclient-changes](https://github.com/spring-projects/spring-ai/tree/v1.0.0-SNAPSHOT-before-chatclient-changes) that you can checkout and do a local build to avoid updating any of your code until you are ready to migrate your code base.
+
+```bash
+git checkout tags/v1.0.0-SNAPSHOT-before-chatclient-changes
+
+./mvnw clean install -DskipTests  
+```
+
+
+**(15.05.2024)**
 
 Renamed POM artifact names:
  - spring-ai-qdrant -> spring-ai-qdrant-store

models/spring-ai-anthropic/src/main/java/org/springframework/ai/anthropic/AnthropicChatClient.java → models/spring-ai-anthropic/src/main/java/org/springframework/ai/anthropic/AnthropicChatModel.java

@@ -26,6 +26,7 @@
 
 import org.slf4j.Logger;
 import org.slf4j.LoggerFactory;
+import org.springframework.ai.chat.ChatModel;
 import reactor.core.publisher.Flux;
 
 import org.springframework.ai.anthropic.api.AnthropicApi;
@@ -38,10 +39,9 @@
 import org.springframework.ai.anthropic.api.AnthropicApi.StreamResponse;
 import org.springframework.ai.anthropic.api.AnthropicApi.Usage;
 import org.springframework.ai.anthropic.metadata.AnthropicChatResponseMetadata;
-import org.springframework.ai.chat.ChatClient;
 import org.springframework.ai.chat.ChatResponse;
 import org.springframework.ai.chat.Generation;
-import org.springframework.ai.chat.StreamingChatClient;
+import org.springframework.ai.chat.StreamingChatModel;
 import org.springframework.ai.chat.messages.MessageType;
 import org.springframework.ai.chat.metadata.ChatGenerationMetadata;
 import org.springframework.ai.chat.prompt.ChatOptions;
@@ -56,16 +56,16 @@
 import org.springframework.util.CollectionUtils;
 
 /**
- * The {@link ChatClient} implementation for the Anthropic service.
+ * The {@link ChatModel} implementation for the Anthropic service.
  *
  * @author Christian Tzolov
  * @since 1.0.0
  */
-public class AnthropicChatClient extends
+public class AnthropicChatModel extends
 		AbstractFunctionCallSupport<AnthropicApi.RequestMessage, AnthropicApi.ChatCompletionRequest, ResponseEntity<AnthropicApi.ChatCompletion>>
-		implements ChatClient, StreamingChatClient {
+		implements ChatModel, StreamingChatModel {
 
-	private static final Logger logger = LoggerFactory.getLogger(AnthropicChatClient.class);
+	private static final Logger logger = LoggerFactory.getLogger(AnthropicChatModel.class);
 
 	public static final String DEFAULT_MODEL_NAME = AnthropicApi.ChatModel.CLAUDE_3_OPUS.getValue();
 
@@ -89,10 +89,10 @@ public class AnthropicChatClient extends
 	public final RetryTemplate retryTemplate;
 
 	/**
-	 * Construct a new {@link AnthropicChatClient} instance.
+	 * Construct a new {@link AnthropicChatModel} instance.
 	 * @param anthropicApi the lower-level API for the Anthropic service.
 	 */
-	public AnthropicChatClient(AnthropicApi anthropicApi) {
+	public AnthropicChatModel(AnthropicApi anthropicApi) {
 		this(anthropicApi,
 				AnthropicChatOptions.builder()
 					.withModel(DEFAULT_MODEL_NAME)
@@ -102,34 +102,34 @@ public AnthropicChatClient(AnthropicApi anthropicApi) {
 	}
 
 	/**
-	 * Construct a new {@link AnthropicChatClient} instance.
+	 * Construct a new {@link AnthropicChatModel} instance.
 	 * @param anthropicApi the lower-level API for the Anthropic service.
 	 * @param defaultOptions the default options used for the chat completion requests.
 	 */
-	public AnthropicChatClient(AnthropicApi anthropicApi, AnthropicChatOptions defaultOptions) {
+	public AnthropicChatModel(AnthropicApi anthropicApi, AnthropicChatOptions defaultOptions) {
 		this(anthropicApi, defaultOptions, RetryUtils.DEFAULT_RETRY_TEMPLATE);
 	}
 
 	/**
-	 * Construct a new {@link AnthropicChatClient} instance.
+	 * Construct a new {@link AnthropicChatModel} instance.
 	 * @param anthropicApi the lower-level API for the Anthropic service.
 	 * @param defaultOptions the default options used for the chat completion requests.
 	 * @param retryTemplate the retry template used to retry the Anthropic API calls.
 	 */
-	public AnthropicChatClient(AnthropicApi anthropicApi, AnthropicChatOptions defaultOptions,
+	public AnthropicChatModel(AnthropicApi anthropicApi, AnthropicChatOptions defaultOptions,
 			RetryTemplate retryTemplate) {
 		this(anthropicApi, defaultOptions, retryTemplate, null);
 	}
 
 	/**
-	 * Construct a new {@link AnthropicChatClient} instance.
+	 * Construct a new {@link AnthropicChatModel} instance.
 	 * @param anthropicApi the lower-level API for the Anthropic service.
 	 * @param defaultOptions the default options used for the chat completion requests.
 	 * @param retryTemplate the retry template used to retry the Anthropic API calls.
 	 * @param functionCallbackContext the function callback context used to store the
 	 * state of the function calls.
 	 */
-	public AnthropicChatClient(AnthropicApi anthropicApi, AnthropicChatOptions defaultOptions,
+	public AnthropicChatModel(AnthropicApi anthropicApi, AnthropicChatOptions defaultOptions,
 			RetryTemplate retryTemplate, FunctionCallbackContext functionCallbackContext) {
 
 		super(functionCallbackContext);
@@ -457,4 +457,9 @@ protected Flux<ResponseEntity<ChatCompletion>> doChatCompletionStream(ChatComple
 				"Streaming (stream=true) is not yet supported. We plan to add streaming support in a future beta version.");
 	}
 
+	@Override
+	public ChatOptions getDefaultOptions() {
+		return AnthropicChatOptions.fromOptions(this.defaultOptions);
+	}
+
 }

models/spring-ai-anthropic/src/main/java/org/springframework/ai/anthropic/AnthropicChatOptions.java

@@ -51,11 +51,11 @@ public class AnthropicChatOptions implements ChatOptions, FunctionCallingOptions
 	private @JsonProperty("top_k") Integer topK;
 
 	/**
-	 * Tool Function Callbacks to register with the ChatClient. For Prompt
+	 * Tool Function Callbacks to register with the ChatModel. For Prompt
 	 * Options the functionCallbacks are automatically enabled for the duration of the
 	 * prompt execution. For Default Options the functionCallbacks are registered but
 	 * disabled by default. Use the enableFunctions to set the functions from the registry
-	 * to be used by the ChatClient chat completion requests.
+	 * to be used by the ChatModel chat completion requests.
 	 */
 	@NestedConfigurationProperty
 	@JsonIgnore
@@ -223,4 +223,17 @@ public void setFunctions(Set<String> functions) {
 		this.functions = functions;
 	}
 
+	public static AnthropicChatOptions fromOptions(AnthropicChatOptions fromOptions) {
+		return builder().withModel(fromOptions.getModel())
+			.withMaxTokens(fromOptions.getMaxTokens())
+			.withMetadata(fromOptions.getMetadata())
+			.withStopSequences(fromOptions.getStopSequences())
+			.withTemperature(fromOptions.getTemperature())
+			.withTopP(fromOptions.getTopP())
+			.withTopK(fromOptions.getTopK())
+			.withFunctionCallbacks(fromOptions.getFunctionCallbacks())
+			.withFunctions(fromOptions.getFunctions())
+			.build();
+	}
+
 }

models/spring-ai-anthropic/src/main/java/org/springframework/ai/anthropic/api/AnthropicApi.java

@@ -26,6 +26,7 @@
 import reactor.core.publisher.Flux;
 import reactor.core.publisher.Mono;
 
+import org.springframework.ai.model.ModelDescription;
 import org.springframework.ai.model.ModelOptionsUtils;
 import org.springframework.ai.retry.RetryUtils;
 import org.springframework.http.HttpHeaders;
@@ -116,7 +117,7 @@ public AnthropicApi(String baseUrl, String anthropicApiKey, String anthropicVers
 	 * "https://docs.anthropic.com/claude/docs/models-overview#model-comparison">model
 	 * comparison</a> for additional details and options.
 	 */
-	public enum ChatModel {
+	public enum ChatModel implements ModelDescription {
 
 		// @formatter:off
 		CLAUDE_3_OPUS("claude-3-opus-20240229"),
@@ -140,6 +141,11 @@ public String getValue() {
 			return this.value;
 		}
 
+		@Override
+		public String getModelName() {
+			return this.value;
+		}
+
 	}
 
 	/**