[FEATURE] support tools enhanced by AOP (#80)

Issues link:
langchain4j/langchain4j#2113

langchain4j-spring-boot-starter/pom.xml

@@ -53,6 +53,13 @@
             <scope>test</scope>
         </dependency>
 
+        <dependency>
+            <groupId>org.springframework.boot</groupId>
+            <artifactId>spring-boot-starter-aop</artifactId>
+            <version>${spring.boot.version}</version>
+            <scope>test</scope>
+        </dependency>
+
         <dependency>
             <groupId>dev.langchain4j</groupId>
             <artifactId>langchain4j-core</artifactId>

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

@@ -1,5 +1,7 @@
 package dev.langchain4j.service.spring;
 
+import dev.langchain4j.agent.tool.Tool;
+import dev.langchain4j.agent.tool.ToolSpecification;
 import dev.langchain4j.memory.ChatMemory;
 import dev.langchain4j.memory.chat.ChatMemoryProvider;
 import dev.langchain4j.model.chat.ChatLanguageModel;
@@ -8,11 +10,20 @@
 import dev.langchain4j.rag.RetrievalAugmentor;
 import dev.langchain4j.rag.content.retriever.ContentRetriever;
 import dev.langchain4j.service.AiServices;
+import dev.langchain4j.service.tool.DefaultToolExecutor;
+import dev.langchain4j.service.tool.ToolExecutor;
 import org.springframework.beans.factory.FactoryBean;
 
+import java.lang.reflect.Method;
+import java.util.Arrays;
+import java.util.HashMap;
 import java.util.List;
+import java.util.Map;
 
+import static dev.langchain4j.agent.tool.ToolSpecifications.toolSpecificationFrom;
 import static dev.langchain4j.internal.Utils.isNullOrEmpty;
+import static org.springframework.aop.framework.AopProxyUtils.ultimateTargetClass;
+import static org.springframework.aop.support.AopUtils.isAopProxy;
 
 class AiServiceFactory implements FactoryBean<Object> {
 
@@ -94,7 +105,13 @@ public Object getObject() {
         }
 
         if (!isNullOrEmpty(tools)) {
-            builder = builder.tools(tools);
+            for (Object tool : tools) {
+                if (isAopProxy(tool)) {
+                    builder = builder.tools(aopEnhancedTools(tool));
+                } else {
+                    builder = builder.tools(tool);
+                }
+            }
         }
 
         return builder.build();
@@ -120,4 +137,21 @@ public boolean isSingleton() {
      * (such as java.io.Closeable.close()) will not be called automatically.
      * Instead, a FactoryBean should implement DisposableBean and delegate any such close call to the underlying object.
      */
+
+    private Map<ToolSpecification, ToolExecutor> aopEnhancedTools(Object enhancedTool) {
+        Map<ToolSpecification, ToolExecutor> toolExecutors = new HashMap<>();
+        Class<?> originalToolClass = ultimateTargetClass(enhancedTool);
+        for (Method originalToolMethod : originalToolClass.getDeclaredMethods()) {
+            if (originalToolMethod.isAnnotationPresent(Tool.class)) {
+                Arrays.stream(enhancedTool.getClass().getDeclaredMethods())
+                      .filter(m -> m.getName().equals(originalToolMethod.getName()))
+                      .findFirst()
+                      .ifPresent(enhancedMethod -> {
+                          ToolSpecification toolSpecification = toolSpecificationFrom(originalToolMethod);
+                          toolExecutors.put(toolSpecification, new DefaultToolExecutor(enhancedTool, enhancedMethod));
+                      });
+            }
+        }
+        return toolExecutors;
+    }
 }

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

@@ -49,7 +49,11 @@ BeanFactoryPostProcessor aiServicesRegisteringBeanFactoryPostProcessor() {
             Set<String> tools = new HashSet<>();
             for (String beanName : beanFactory.getBeanDefinitionNames()) {
                 try {
-                    Class<?> beanClass = Class.forName(beanFactory.getBeanDefinition(beanName).getBeanClassName());
+                    String beanClassName = beanFactory.getBeanDefinition(beanName).getBeanClassName();
+                    if (beanClassName == null) {
+                        continue;
+                    }
+                    Class<?> beanClass = Class.forName(beanClassName);
                     for (Method beanMethod : beanClass.getDeclaredMethods()) {
                         if (beanMethod.isAnnotationPresent(Tool.class)) {
                             tools.add(beanName);

langchain4j-spring-boot-starter/src/test/java/dev/langchain4j/service/spring/mode/automatic/withTools/AiServicesAutoConfigIT.java

@@ -1,14 +1,22 @@
 package dev.langchain4j.service.spring.mode.automatic.withTools;
 
 import dev.langchain4j.service.spring.AiServicesAutoConfig;
+import dev.langchain4j.service.spring.mode.automatic.withTools.aop.ToolObserverAspect;
 import org.junit.jupiter.api.Test;
 import org.springframework.boot.autoconfigure.AutoConfigurations;
 import org.springframework.boot.test.context.runner.ApplicationContextRunner;
 
 import static dev.langchain4j.service.spring.mode.ApiKeys.OPENAI_API_KEY;
+import static dev.langchain4j.service.spring.mode.automatic.withTools.AopEnhancedTools.TOOL_OBSERVER_KEY;
+import static dev.langchain4j.service.spring.mode.automatic.withTools.AopEnhancedTools.TOOL_OBSERVER_KEY_NAME_DESCRIPTION;
+import static dev.langchain4j.service.spring.mode.automatic.withTools.AopEnhancedTools.TOOL_OBSERVER_PACKAGE_NAME;
+import static dev.langchain4j.service.spring.mode.automatic.withTools.AopEnhancedTools.TOOL_OBSERVER_PACKAGE_NAME_DESCRIPTION;
 import static dev.langchain4j.service.spring.mode.automatic.withTools.PackagePrivateTools.CURRENT_TIME;
 import static dev.langchain4j.service.spring.mode.automatic.withTools.PublicTools.CURRENT_DATE;
 import static org.assertj.core.api.Assertions.assertThat;
+import static org.junit.jupiter.api.Assertions.assertEquals;
+import static org.junit.jupiter.api.Assertions.assertFalse;
+import static org.junit.jupiter.api.Assertions.assertTrue;
 
 class AiServicesAutoConfigIT {
 
@@ -61,6 +69,46 @@ void should_create_AI_service_with_tool_that_is_package_private_method_in_packag
                 });
     }
 
+    @Test
+    void should_create_AI_service_with_tool_which_is_enhanced_by_spring_aop() {
+        contextRunner
+                .withPropertyValues(
+                        "langchain4j.open-ai.chat-model.api-key=" + OPENAI_API_KEY,
+                        "langchain4j.open-ai.chat-model.temperature=0.0",
+                        "langchain4j.open-ai.chat-model.log-requests=true",
+                        "langchain4j.open-ai.chat-model.log-responses=true"
+                )
+                .withUserConfiguration(AiServiceWithToolsApplication.class)
+                .run(context -> {
+
+                    // given
+                    AiServiceWithTools aiService = context.getBean(AiServiceWithTools.class);
+
+                    // when
+                    String answer = aiService.chat("Which package is the @ToolObserver annotation located in? " +
+                            "And what is the key of the @ToolObserver annotation?" +
+                            "And What is the current time?");
+
+                    System.out.println("Answer: " + answer);
+
+                    // then should use AopEnhancedTools.getAspectPackage()
+                    // & AopEnhancedTools.getToolObserverKey()
+                    // & PackagePrivateTools.getCurrentTime()
+                    assertThat(answer).contains(TOOL_OBSERVER_PACKAGE_NAME);
+                    assertThat(answer).contains(TOOL_OBSERVER_KEY);
+                    assertThat(answer).contains(String.valueOf(CURRENT_TIME.getMinute()));
+
+                    // and AOP aspect should be called
+                    // & only for getToolObserverKey() which is annotated with @ToolObserver
+                    ToolObserverAspect aspect = context.getBean(ToolObserverAspect.class);
+                    assertTrue(aspect.aspectHasBeenCalled());
+
+                    assertEquals(1, aspect.getObservedTools().size());
+                    assertTrue(aspect.getObservedTools().contains(TOOL_OBSERVER_KEY_NAME_DESCRIPTION));
+                    assertFalse(aspect.getObservedTools().contains(TOOL_OBSERVER_PACKAGE_NAME_DESCRIPTION));
+                });
+    }
+
     // TODO tools which are not @Beans?
     // TODO negative cases
     // TODO no @AiServices in app, just models

langchain4j-spring-boot-starter/src/test/java/dev/langchain4j/service/spring/mode/automatic/withTools/AopEnhancedTools.java

@@ -0,0 +1,28 @@
+package dev.langchain4j.service.spring.mode.automatic.withTools;
+
+import dev.langchain4j.agent.tool.Tool;
+import dev.langchain4j.service.spring.mode.automatic.withTools.aop.ToolObserver;
+import org.springframework.stereotype.Component;
+
+@Component
+public class AopEnhancedTools {
+
+    public static final String TOOL_OBSERVER_PACKAGE_NAME_DESCRIPTION =
+            "Find the package directory where @ToolObserver is located.";
+    public static final String TOOL_OBSERVER_PACKAGE_NAME = ToolObserver.class.getPackageName();
+
+    public static final String TOOL_OBSERVER_KEY_NAME_DESCRIPTION =
+            "Find the key name of @ToolObserver";
+    public static final String TOOL_OBSERVER_KEY = "AOP_ENHANCED_TOOLS_SUPPORT_@_1122";
+
+    @Tool(TOOL_OBSERVER_PACKAGE_NAME_DESCRIPTION)
+    public String getToolObserverPackageName() {
+        return TOOL_OBSERVER_PACKAGE_NAME;
+    }
+
+    @ToolObserver(key = TOOL_OBSERVER_KEY)
+    @Tool(TOOL_OBSERVER_KEY_NAME_DESCRIPTION)
+    public String getToolObserverKey() {
+        return TOOL_OBSERVER_KEY;
+    }
+}

langchain4j-spring-boot-starter/src/test/java/dev/langchain4j/service/spring/mode/automatic/withTools/aop/ToolObserver.java

@@ -0,0 +1,18 @@
+package dev.langchain4j.service.spring.mode.automatic.withTools.aop;
+
+import java.lang.annotation.ElementType;
+import java.lang.annotation.Retention;
+import java.lang.annotation.RetentionPolicy;
+import java.lang.annotation.Target;
+
+@Target({ElementType.METHOD})
+@Retention(RetentionPolicy.RUNTIME)
+public @interface ToolObserver {
+
+    /**
+     * key just for example
+     *
+     * @return the key
+     */
+    String key();
+}

langchain4j-spring-boot-starter/src/test/java/dev/langchain4j/service/spring/mode/automatic/withTools/aop/ToolObserverAspect.java

@@ -0,0 +1,47 @@
+package dev.langchain4j.service.spring.mode.automatic.withTools.aop;
+
+import dev.langchain4j.agent.tool.Tool;
+import org.aspectj.lang.ProceedingJoinPoint;
+import org.aspectj.lang.annotation.Around;
+import org.aspectj.lang.annotation.Aspect;
+import org.aspectj.lang.reflect.MethodSignature;
+import org.springframework.stereotype.Component;
+
+import java.util.ArrayList;
+import java.util.Arrays;
+import java.util.List;
+
+@Aspect
+@Component
+public class ToolObserverAspect {
+
+    private final List<String> observedTools = new ArrayList<>();
+
+    @Around("@annotation(toolObserver)")
+    public Object around(ProceedingJoinPoint joinPoint, ToolObserver toolObserver) throws Throwable {
+        var signature = (MethodSignature) joinPoint.getSignature();
+        var method = signature.getMethod();
+        String methodName = method.getName();
+        if (method.isAnnotationPresent(Tool.class)) {
+            Tool toolAnnotation = method.getAnnotation(Tool.class);
+            observedTools.addAll(Arrays.asList(toolAnnotation.value()));
+            System.out.printf("Found @Tool %s for method: %s%n%n", Arrays.toString(toolAnnotation.value()), methodName);
+        }
+        Object result = joinPoint.proceed();
+        System.out.printf(" | key: %s%n | Method name: %s%n | Method arguments: %s%n | Return type: %s%n | Method return value: %s%n%n",
+                toolObserver.key(),
+                methodName,
+                Arrays.toString(joinPoint.getArgs()),
+                method.getReturnType().getName(),
+                result);
+        return result;
+    }
+
+    public boolean aspectHasBeenCalled() {
+        return !observedTools.isEmpty();
+    }
+
+    public List<String> getObservedTools() {
+        return observedTools;
+    }
+}