Fix #2133 Spring boot starter breaks configuration classes (#79)

Fixes langchain4j/langchain4j#2133

The problem is `beanfactory.getBeanswithanNotation()`. It creates an
instance of the Bean in advance.


https://github.com/langchain4j/langchain4j-spring/blob/405fddafbcf8c3463c7211dc82b7c5887f9531c6/langchain4j-spring-boot-starter/src/main/java/dev/langchain4j/service/spring/AiServiceScannerProcessor.java#L49

Author: qing-wq

langchain4j-spring-boot-starter/src/main/java/dev/langchain4j/service/spring/AiServiceScannerProcessor.java

@@ -46,25 +46,27 @@ private Set<String> getBasePackages(ConfigurableListableBeanFactory beanFactory)
     }
 
     private void addComponentScanPackages(ConfigurableListableBeanFactory beanFactory, Set<String> collectedBasePackages) {
-        beanFactory.getBeansWithAnnotation(ComponentScan.class).forEach((beanName, instance) -> {
-            Set<ComponentScan> componentScans = AnnotatedElementUtils.getMergedRepeatableAnnotations(instance.getClass(), ComponentScan.class);
-            for (ComponentScan componentScan : componentScans) {
-                Set<String> basePackages = new LinkedHashSet<>();
-                String[] basePackagesArray = componentScan.basePackages();
-                for (String pkg : basePackagesArray) {
-                    String[] tokenized = StringUtils.tokenizeToStringArray(this.environment.resolvePlaceholders(pkg),
-                            ConfigurableApplicationContext.CONFIG_LOCATION_DELIMITERS);
-                    Collections.addAll(basePackages, tokenized);
-                }
-                for (Class<?> clazz : componentScan.basePackageClasses()) {
-                    basePackages.add(ClassUtils.getPackageName(clazz));
-                }
-                if (basePackages.isEmpty()) {
-                    basePackages.add(ClassUtils.getPackageName(instance.getClass()));
+        for (String beanName : beanFactory.getBeanNamesForAnnotation(ComponentScan.class)) {
+            Class<?> beanClass = beanFactory.getType(beanName);
+            if (beanClass != null) {
+                Set<ComponentScan> componentScans = AnnotatedElementUtils.getMergedRepeatableAnnotations(beanClass, ComponentScan.class);
+                for (ComponentScan componentScan : componentScans) {
+                    Set<String> basePackages = new LinkedHashSet<>();
+                    for (String pkg : componentScan.basePackages()) {
+                        String[] tokenized = StringUtils.tokenizeToStringArray(this.environment.resolvePlaceholders(pkg),
+                                ConfigurableApplicationContext.CONFIG_LOCATION_DELIMITERS);
+                        Collections.addAll(basePackages, tokenized);
+                    }
+                    for (Class<?> clazz : componentScan.basePackageClasses()) {
+                        basePackages.add(ClassUtils.getPackageName(clazz));
+                    }
+                    if (basePackages.isEmpty()) {
+                        basePackages.add(ClassUtils.getPackageName(beanClass));
+                    }
+                    collectedBasePackages.addAll(basePackages);
                 }
-                collectedBasePackages.addAll(basePackages);
             }
-        });
+        }
     }
 
     private void removeAiServicesWithInactiveProfiles(BeanDefinitionRegistry registry) {

langchain4j-spring-boot-starter/src/test/java/dev/langchain4j/service/spring/mode/automatic/Issue2133/TestAutowireAiServiceApplication.java

@@ -0,0 +1,24 @@
+package dev.langchain4j.service.spring.mode.automatic.Issue2133;
+
+import org.springframework.beans.factory.annotation.Autowired;
+import org.springframework.boot.SpringApplication;
+import org.springframework.boot.autoconfigure.SpringBootApplication;
+
+/**
+ * @author: qing
+ * @Date: 2024/11/20
+ */
+@SpringBootApplication
+public class TestAutowireAiServiceApplication {
+
+    @Autowired
+    TestAutowireConfiguration testAutowireConfiguration;
+
+    public static void main(String[] args) {
+        SpringApplication.run(TestAutowireAiServiceApplication.class, args);
+    }
+
+    TestAutowireConfiguration getConfiguration() {
+        return testAutowireConfiguration;
+    }
+}

langchain4j-spring-boot-starter/src/test/java/dev/langchain4j/service/spring/mode/automatic/Issue2133/TestAutowireClassAiServiceIT.java

@@ -0,0 +1,28 @@
+package dev.langchain4j.service.spring.mode.automatic.Issue2133;
+
+import dev.langchain4j.service.spring.AiServicesAutoConfig;
+import org.junit.jupiter.api.Test;
+import org.springframework.boot.autoconfigure.AutoConfigurations;
+import org.springframework.boot.test.context.runner.ApplicationContextRunner;
+
+import static org.junit.jupiter.api.Assertions.assertNotNull;
+
+class TestAutowireClassAiServiceIT {
+
+    ApplicationContextRunner contextRunner = new ApplicationContextRunner()
+            .withConfiguration(AutoConfigurations.of(AiServicesAutoConfig.class));
+
+    @Test
+    void should_get_configuration_class() {
+        contextRunner
+                .withUserConfiguration(TestAutowireAiServiceApplication.class)
+                .withBean(TestAutowireConfiguration.class)
+                .run(context -> {
+                    // given
+                    TestAutowireAiServiceApplication application = context.getBean(TestAutowireAiServiceApplication.class);
+
+                    // should get the configuration class
+                    assertNotNull(application.getConfiguration(), "TestConfiguration class should be not null");
+                });
+    }
+}

langchain4j-spring-boot-starter/src/test/java/dev/langchain4j/service/spring/mode/automatic/Issue2133/TestAutowireConfiguration.java

@@ -0,0 +1,11 @@
+package dev.langchain4j.service.spring.mode.automatic.Issue2133;
+
+import org.springframework.context.annotation.Configuration;
+
+/**
+ * @author: qing
+ * @Date: 2024/11/20
+ */
+@Configuration
+class TestAutowireConfiguration {
+}