Split logic of sample-app into service and controller

sample-code/spring-app/pom.xml

@@ -95,6 +95,11 @@
       <artifactId>spring-webmvc</artifactId>
       <version>${springframework.version}</version>
     </dependency>
+    <dependency>
+      <groupId>org.springframework</groupId>
+      <artifactId>spring-beans</artifactId>
+      <version>${springframework.version}</version>
+    </dependency>
     <dependency>
       <groupId>com.google.code.findbugs</groupId>
       <artifactId>jsr305</artifactId>
@@ -111,6 +116,10 @@
       <groupId>com.fasterxml.jackson.core</groupId>
       <artifactId>jackson-core</artifactId>
     </dependency>
+    <dependency>
+      <groupId>com.fasterxml.jackson.core</groupId>
+      <artifactId>jackson-annotations</artifactId>
+    </dependency>
     <!-- scope "runtime" -->
     <dependency>
       <groupId>ch.qos.logback</groupId>

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

@@ -34,7 +34,7 @@
 /** Endpoints for OpenAI operations */
 @Slf4j
 @RestController
-class OpenAiController {
+public class OpenAiController {
   /**
    * Chat request to OpenAI
    *
@@ -123,7 +123,13 @@ ResponseEntity<ResponseBodyEmitter> streamChatCompletion() {
     return ResponseEntity.ok().contentType(MediaType.TEXT_EVENT_STREAM).body(emitter);
   }
 
-  static void send(@Nonnull final ResponseBodyEmitter emitter, @Nonnull final String chunk) {
+  /**
+   * Send a chunk to the emitter
+   *
+   * @param emitter The emitter to send the chunk to
+   * @param chunk The chunk to send
+   */
+  public static void send(@Nonnull final ResponseBodyEmitter emitter, @Nonnull final String chunk) {
     try {
       emitter.send(chunk);
     } catch (final IOException e) {