🐛 fix #1030 The Spring Boot jar fails to run when using @AiServic…

[clear2x]

The Spring Boot jar fails to run when using @aiservice due to Reflections[0.10.2]

Relevant Links:

• [BUG] The interface decorated with "@AiService" cannot be scanned by "AiServicesAutoConfig" when running the SpringBoot Jar package. langchain4j#1030
• [0.10.2] Reflections does not detect any classes, if base class (or package prefix) is passed as argument, and application is running as a jar ronmamo/reflections#373

[langchain4j]

Hi @clear2x almost all tests in langchain4j-spring-boot-starter module are failing with this change, could you please check?

[clear2x]

Sorry, I have already fixed it.

[clear2x]

I found that the dev.langchain4j.service.spring.mode.automatic.withTools.AiServicesAutoConfigIT#should_create_AI_service_with_tool_that_is_package_private_method_in_package_private_class case fails to execute both before and after the modification.

[langchain4j]

Something fishy is going on... Why is filtering required? Why does getTypesAnnotatedWith return all classes, even if we specify basePackage?

[clear2x]

forPackage(basePackage)); 

This code calls the following piece of code :

public static Collection<URL> forResource(String resourceName, ClassLoader... classLoaders) {
        final List<URL> result = new ArrayList<>();
        final ClassLoader[] loaders = classLoaders(classLoaders);
        for (ClassLoader classLoader : loaders) {
            try {
                final Enumeration<URL> urls = classLoader.getResources(resourceName);
                while (urls.hasMoreElements()) {
                    final URL url = urls.nextElement();
                    int index = url.toExternalForm().lastIndexOf(resourceName);
                    if (index != -1) {
                    	// Add old url as contextUrl to support exotic url handlers
                        result.add(new URL(url, url.toExternalForm().substring(0, index)));
                    } else {
                        result.add(url);
                    }
                }
            } catch (IOException e) {
                if (Reflections.log != null) {
                    Reflections.log.error("error getting resources for " + resourceName, e);
                }
            }
        }
        return distinctUrls(result);
    }

where the key part is:

int index = url.toExternalForm().lastIndexOf(resourceName);
if (index != -1) {
 // Add old url as contextUrl to support exotic url handlers
    result.add(new URL(url, url.toExternalForm().substring(0, index)));
} else {
    result.add(url);
}

This segment extracts a part of the URL, and after extraction, it becomes test-classes.

Our goal is to find all AI Services under the base package and its sub-packages, so we perform filtering here .

[clear2x]

A few other thoughts...... "In jar files, Reflections cannot scan classes." This issue has been discussed extensively in the link above. We might also consider not relying on Reflections and directly using Spring's related methods to achieve our goal.

[langchain4j]

@clear2x instead of Reflections, which spring methods can be used? I tried to use some, but they ignore interfaces

[clear2x]

ResourcePatternResolver, PathMatchingResourcePatternResolver, StandardEnvironment, and SimpleMetadataReaderFactory can work together to achieve our goal.

public class AnnotationUtils extends org.springframework.core.annotation.AnnotationUtils {
    private static final PathMatchingResourcePatternResolver RESOLVER = new PathMatchingResourcePatternResolver();
    private static final SimpleMetadataReaderFactory REGISTER = new SimpleMetadataReaderFactory();
    private static final StandardEnvironment ENVIRONMENT = new StandardEnvironment();

    public static String getResourcePath(String packagePath) {
        if (StringUtils.isEmpty(packagePath)) {
            return "";
        }
        return ResourcePatternResolver.CLASSPATH_ALL_URL_PREFIX
                + ClassUtils.convertClassNameToResourcePath(ENVIRONMENT.resolveRequiredPlaceholders(packagePath))
                + '/' + "**/*.class";
    }

    public static Set<Class<?>> getClazzFromAnnotation(String pkgPath, Class<? extends Annotation> annoClazz) {
        String pathPackage = getResourcePath(pkgPath);
        log.info("pathPackage: {}", pathPackage);
        Set<Class<?>> paths = new HashSet<>();
        Resource[] resources;
        try {
            resources = RESOLVER.getResources(pathPackage);
        } catch (IOException e) {
            return new HashSet<>();
        }
        for (Resource resource : resources) {
            MetadataReader metadataReader = null;
            try {
                metadataReader = REGISTER.getMetadataReader(resource);
            } catch (IOException e) {
                continue;
            }
            AnnotationMetadata annotationMetadata = metadataReader.getAnnotationMetadata();
            if (!annotationMetadata.hasAnnotation(annoClazz.getName())) {
                continue;
            }
            ClassMetadata classMetadata = metadataReader.getClassMetadata();
            String className = classMetadata.getClassName();
            try {
                ClassLoader classLoader = Thread.currentThread().getContextClassLoader();
                Class<?> clazz = classLoader.loadClass(className);
                paths.add(clazz);
            } catch (ClassNotFoundException e) {
                log.warn(e.getMessage());
            }
        }
        return paths;
    }

}