Cleanup changes for review and add docs.

Author: rpanackal

orchestration/src/main/java/com/sap/ai/sdk/orchestration/AssistantMessage.java

@@ -2,11 +2,24 @@
 
 import com.sap.ai.sdk.orchestration.client.model.ChatMessage;
 import javax.annotation.Nonnull;
+import lombok.Value;
+import lombok.experimental.Accessors;
 
-public record AssistantMessage(@Nonnull String content) implements Message {
+/** Represents a chat message as 'assistant' to the orchestration service. */
+@Value
+@Accessors(fluent = true)
+public class AssistantMessage implements Message {
 
-  public static final String ROLE = "assistant";
+  /** The role of the assistant. */
+  @Nonnull public static final String ROLE = "assistant";
 
+  @Nonnull String content;
+
+  /**
+   * Converts the message to a serializable ChatMessage object.
+   *
+   * @return the corresponding {@code ChatMessage} object.
+   */
   @Nonnull
   public ChatMessage toChatMessage() {
     return ChatMessage.create().role(ROLE).content(content);

orchestration/src/main/java/com/sap/ai/sdk/orchestration/Message.java

@@ -1,7 +1,16 @@
 package com.sap.ai.sdk.orchestration;
 
 import com.sap.ai.sdk.orchestration.client.model.ChatMessage;
+import javax.annotation.Nonnull;
 
+/** Represents a chat message to the orchestration service. */
 public sealed interface Message permits UserMessage, AssistantMessage, SystemMessage {
-  public ChatMessage toChatMessage();
+
+  /**
+   * Converts the message to a serializable ChatMessage object.
+   *
+   * @return the corresponding {@code ChatMessage} object.
+   */
+  @Nonnull
+  ChatMessage toChatMessage();
 }

orchestration/src/main/java/com/sap/ai/sdk/orchestration/SystemMessage.java

@@ -2,11 +2,24 @@
 
 import com.sap.ai.sdk.orchestration.client.model.ChatMessage;
 import javax.annotation.Nonnull;
+import lombok.Value;
+import lombok.experimental.Accessors;
 
-public record SystemMessage(@Nonnull String content) implements Message {
+/** Represents a chat message as 'system' to the orchestration service. */
+@Value
+@Accessors(fluent = true)
+public class SystemMessage implements Message {
 
-  public static final String ROLE = "system";
+  /** The role of the assistant. */
+  @Nonnull public static final String ROLE = "system";
 
+  @Nonnull String content;
+
+  /**
+   * Converts the message to a serializable ChatMessage object.
+   *
+   * @return the corresponding {@code ChatMessage} object.
+   */
   @Nonnull
   public ChatMessage toChatMessage() {
     return ChatMessage.create().role(ROLE).content(content);

orchestration/src/main/java/com/sap/ai/sdk/orchestration/UserMessage.java

@@ -2,11 +2,24 @@
 
 import com.sap.ai.sdk.orchestration.client.model.ChatMessage;
 import javax.annotation.Nonnull;
+import lombok.Value;
+import lombok.experimental.Accessors;
 
-public record UserMessage(@Nonnull String content) implements Message {
+/** Represents a chat message as 'user' to the orchestration service. */
+@Value
+@Accessors(fluent = true)
+public class UserMessage implements Message {
 
-  public static final String ROLE = "user";
+  /** The role of the assistant. */
+  @Nonnull public static final String ROLE = "user";
 
+  @Nonnull String content;
+
+  /**
+   * Converts the message to a serializable ChatMessage object.
+   *
+   * @return the corresponding {@code ChatMessage} object.
+   */
   @Nonnull
   public ChatMessage toChatMessage() {
     return ChatMessage.create().role(ROLE).content(content);

sample-code/spring-app/src/main/java/com/sap/ai/sdk/app/controllers/OrchestrationController.java

@@ -13,7 +13,6 @@
 import com.sap.ai.sdk.orchestration.OrchestrationPrompt;
 import com.sap.ai.sdk.orchestration.SystemMessage;
 import com.sap.ai.sdk.orchestration.UserMessage;
-import com.sap.ai.sdk.orchestration.client.model.ChatMessage;
 import com.sap.ai.sdk.orchestration.client.model.DPIEntities;
 import com.sap.ai.sdk.orchestration.client.model.Template;
 import java.util.List;
@@ -55,10 +54,8 @@ public OrchestrationChatResponse completion() {
   @Nonnull
   public OrchestrationChatResponse template() {
     final var template =
-        ChatMessage.create()
-            .role("user")
-            .content("Reply with 'Orchestration Service is working!' in {{?language}}");
-    final var templatingConfig = Template.create().template(List.of(template));
+        new UserMessage("Reply with 'Orchestration Service is working!' in {{?language}}");
+    final var templatingConfig = Template.create().template(List.of(template.toChatMessage()));
     final var configWithTemplate = config.withTemplateConfig(templatingConfig);
 
     final var inputParams = Map.of("language", "German");