Bean Processing and Extensibility

/**
 * Processor interface for bean definition modification
 * @param <T> The bean type
 */
public interface BeanDefinitionProcessor<T> {
    /**
     * Process a bean definition and optionally return a modified version
     * @param beanDefinition The original bean definition
     * @param context The bean context
     * @return The processed bean definition
     */
    BeanDefinition<T> process(BeanDefinition<T> beanDefinition, BeanContext context);
    
    /**
     * Check if this processor applies to the given bean definition
     * @param beanDefinition The bean definition to check
     * @return true if this processor should process the bean definition
     */
    default boolean supports(BeanDefinition<T> beanDefinition) {
        return true;
    }
}

/**
 * Processor interface for executable method processing
 * @param <T> The bean type
 */
public interface ExecutableMethodProcessor<T> {
    /**
     * Process an executable method
     * @param beanDefinition The bean definition containing the method
     * @param method The executable method to process
     */
    void process(BeanDefinition<?> beanDefinition, ExecutableMethod<T, ?> method);
    
    /**
     * Get the method annotation type this processor handles
     * @return The annotation type
     */
    Class<? extends Annotation> getAnnotationType();
}

import io.micronaut.context.processor.BeanDefinitionProcessor;
import io.micronaut.context.processor.ExecutableMethodProcessor;
import jakarta.inject.Singleton;

@Singleton
public class AuditBeanProcessor implements BeanDefinitionProcessor<Object> {
    
    @Override
    public BeanDefinition<Object> process(BeanDefinition<Object> beanDefinition, BeanContext context) {
        if (beanDefinition.hasAnnotation(Auditable.class)) {
            // Wrap bean definition to add auditing capabilities
            return new AuditableBeanDefinition<>(beanDefinition);
        }
        return beanDefinition;
    }
    
    @Override
    public boolean supports(BeanDefinition<Object> beanDefinition) {
        return beanDefinition.hasAnnotation(Auditable.class);
    }
}

@Singleton
public class TimedMethodProcessor implements ExecutableMethodProcessor<Object> {
    
    @Override
    public void process(BeanDefinition<?> beanDefinition, ExecutableMethod<Object, ?> method) {
        if (method.hasAnnotation(Timed.class)) {
            // Register timing interceptor for this method
            registerTimingInterceptor(beanDefinition, method);
        }
    }
    
    @Override
    public Class<? extends Annotation> getAnnotationType() {
        return Timed.class;
    }
    
    private void registerTimingInterceptor(BeanDefinition<?> beanDefinition, ExecutableMethod<?, ?> method) {
        // Implementation to register timing interceptor
    }
}

/**
 * Registry for bean definition metadata and introspection
 */
public interface BeanDefinitionRegistry {
    /**
     * Check if a bean of the given type exists
     * @param beanType The bean type
     * @return true if bean exists
     */
    <T> boolean containsBean(Class<T> beanType);
    
    /**
     * Check if a bean exists with qualifier
     * @param beanType The bean type
     * @param qualifier The qualifier
     * @return true if bean exists
     */
    <T> boolean containsBean(Class<T> beanType, Qualifier<T> qualifier);
    
    /**
     * Find bean definition for the given type
     * @param beanType The bean type
     * @return Optional bean definition
     */
    <T> Optional<BeanDefinition<T>> findBeanDefinition(Class<T> beanType);
    
    /**
     * Find bean definition with qualifier
     * @param beanType The bean type
     * @param qualifier The qualifier
     * @return Optional bean definition
     */
    <T> Optional<BeanDefinition<T>> findBeanDefinition(Class<T> beanType, Qualifier<T> qualifier);
    
    /**
     * Get all bean definitions for the given type
     * @param beanType The bean type
     * @return Collection of bean definitions
     */
    <T> Collection<BeanDefinition<T>> getBeanDefinitions(Class<T> beanType);
    
    /**
     * Get single bean definition for the given type
     * @param beanType The bean type
     * @return Bean definition
     * @throws NoSuchBeanException if not found
     * @throws NonUniqueBeanException if multiple found
     */
    <T> BeanDefinition<T> getBeanDefinition(Class<T> beanType);
    
    /**
     * Get all bean definitions
     * @return Collection of all bean definitions
     */
    Collection<BeanDefinition<?>> getAllBeanDefinitions();
    
    /**
     * Get bean definitions by annotation
     * @param annotation The annotation type
     * @return Collection of matching bean definitions
     */
    Collection<BeanDefinition<?>> getBeanDefinitionsForAnnotation(Class<? extends Annotation> annotation);
}

/**
 * Bean introspection interface for reflection-free property access
 * @param <T> The bean type
 */
public interface BeanIntrospection<T> {
    /**
     * Get the bean type
     * @return The bean type
     */
    Class<T> getBeanType();
    
    /**
     * Instantiate the bean
     * @param args Constructor arguments
     * @return Bean instance
     */
    T instantiate(Object... args);
    
    /**
     * Get all bean properties
     * @return Collection of bean properties
     */
    Collection<BeanProperty<T, Object>> getBeanProperties();
    
    /**
     * Get bean property by name
     * @param name Property name
     * @return Optional bean property
     */
    Optional<BeanProperty<T, Object>> getProperty(String name);
    
    /**
     * Get required bean property by name
     * @param name Property name
     * @return Bean property
     * @throws IntrospectionException if property not found
     */
    BeanProperty<T, Object> getRequiredProperty(String name);
    
    /**
     * Get indexed bean properties (array/collection properties)
     * @return Collection of indexed properties
     */
    Collection<BeanProperty<T, Object>> getIndexedProperties();
    
    /**
     * Get constructor arguments
     * @return Array of constructor arguments
     */
    Argument<?>[] getConstructorArguments();
}

import io.micronaut.core.beans.BeanIntrospection;
import io.micronaut.core.beans.BeanProperty;

public class BeanProcessor {
    
    public void processBeanProperties(Object bean) {
        BeanIntrospection<Object> introspection = BeanIntrospection.getIntrospection(bean.getClass());
        
        // Process all properties
        for (BeanProperty<Object, Object> property : introspection.getBeanProperties()) {
            Object value = property.get(bean);
            System.out.println("Property " + property.getName() + " = " + value);
            
            // Validate or transform property values
            if (property.hasAnnotation(NotNull.class) && value == null) {
                throw new ValidationException("Property " + property.getName() + " cannot be null");
            }
        }
        
        // Copy properties between beans
        BeanIntrospection<Object> targetIntrospection = BeanIntrospection.getIntrospection(TargetBean.class);
        Object targetBean = targetIntrospection.instantiate();
        
        introspection.getBeanProperties().forEach(sourceProperty -> {
            targetIntrospection.getProperty(sourceProperty.getName())
                .ifPresent(targetProperty -> {
                    Object value = sourceProperty.get(bean);
                    targetProperty.set(targetBean, value);
                });
        });
    }
}

/**
 * Locator for optimized executable method handles
 */
public interface ExecutionHandleLocator {
    /**
     * Find execution handle for method
     * @param beanType The bean type
     * @param method The method name
     * @param argumentTypes The argument types
     * @return Optional execution handle
     */
    <T, R> Optional<ExecutionHandle<T, R>> findExecutionHandle(Class<T> beanType, String method, Class<?>... argumentTypes);
    
    /**
     * Get required execution handle for method
     * @param beanType The bean type
     * @param method The method name
     * @param argumentTypes The argument types
     * @return Execution handle
     * @throws NoSuchMethodException if method not found
     */
    <T, R> ExecutionHandle<T, R> getExecutionHandle(Class<T> beanType, String method, Class<?>... argumentTypes);
    
    /**
     * Find all execution handles for bean type
     * @param beanType The bean type
     * @return Stream of execution handles
     */
    <T> Stream<ExecutionHandle<T, ?>> findExecutionHandles(Class<T> beanType);
}

/**
 * Handle for optimized method execution
 * @param <T> The bean type
 * @param <R> The return type
 */
public interface ExecutionHandle<T, R> {
    /**
     * Invoke the method on the target instance
     * @param target The target instance
     * @param arguments The method arguments
     * @return The method result
     */
    R invoke(T target, Object... arguments);
    
    /**
     * Get the executable method
     * @return The executable method
     */
    ExecutableMethod<T, R> getExecutableMethod();
    
    /**
     * Get the target bean type
     * @return The bean type
     */
    Class<T> getDeclaringType();
    
    /**
     * Get the method name
     * @return The method name
     */
    String getMethodName();
    
    /**
     * Get argument types
     * @return Array of argument types
     */
    Argument<?>[] getArguments();
    
    /**
     * Get return type
     * @return The return type argument
     */
    Argument<R> getReturnType();
}

import io.micronaut.inject.ExecutionHandle;
import io.micronaut.inject.ExecutionHandleLocator;

@Singleton
public class DynamicMethodInvoker {
    
    private final ExecutionHandleLocator handleLocator;
    
    public DynamicMethodInvoker(ExecutionHandleLocator handleLocator) {
        this.handleLocator = handleLocator;
    }
    
    public Object invokeMethod(Object target, String methodName, Object... args) {
        Class<?>[] argTypes = Arrays.stream(args)
            .map(Object::getClass)
            .toArray(Class<?>[]::new);
            
        ExecutionHandle<Object, Object> handle = handleLocator
            .findExecutionHandle(target.getClass(), methodName, argTypes)
            .orElseThrow(() -> new NoSuchMethodException("Method not found: " + methodName));
            
        return handle.invoke(target, args);
    }
    
    public void invokeAllMethods(Object target, String pattern) {
        handleLocator.findExecutionHandles(target.getClass())
            .filter(handle -> handle.getMethodName().matches(pattern))
            .forEach(handle -> {
                try {
                    handle.invoke(target);
                } catch (Exception e) {
                    System.err.println("Failed to invoke " + handle.getMethodName() + ": " + e.getMessage());
                }
            });
    }
}

@Singleton
public class ConditionalBeanProcessor implements BeanDefinitionProcessor<Object> {
    
    private final Environment environment;
    
    public ConditionalBeanProcessor(Environment environment) {
        this.environment = environment;
    }
    
    @Override
    public BeanDefinition<Object> process(BeanDefinition<Object> beanDefinition, BeanContext context) {
        if (beanDefinition.hasAnnotation(ConditionalOnProperty.class)) {
            String property = beanDefinition.getAnnotation(ConditionalOnProperty.class)
                .stringValue("name").orElse("");
            
            if (!environment.containsProperty(property)) {
                // Return disabled bean definition
                return new DisabledBeanDefinition<>(beanDefinition);
            }
        }
        return beanDefinition;
    }
}

@Singleton
public class CachingMethodProcessor implements ExecutableMethodProcessor<Object> {
    
    private final CacheManager cacheManager;
    
    public CachingMethodProcessor(CacheManager cacheManager) {
        this.cacheManager = cacheManager;
    }
    
    @Override
    public void process(BeanDefinition<?> beanDefinition, ExecutableMethod<Object, ?> method) {
        if (method.hasAnnotation(Cacheable.class)) {
            String cacheName = method.getAnnotation(Cacheable.class)
                .stringValue().orElse("default");
            
            // Register caching interceptor
            registerCachingInterceptor(beanDefinition, method, cacheName);
        }
    }
    
    @Override
    public Class<? extends Annotation> getAnnotationType() {
        return Cacheable.class;
    }
    
    private void registerCachingInterceptor(BeanDefinition<?> beanDefinition, 
                                          ExecutableMethod<?, ?> method, 
                                          String cacheName) {
        // Implementation to register caching interceptor
    }
}

public interface BeanProperty<B, T> {
    String getName();
    Class<T> getType();
    Argument<T> asArgument();
    
    T get(B bean);
    void set(B bean, T value);
    
    boolean isReadOnly();
    boolean isWriteOnly();
    boolean hasAnnotation(Class<? extends Annotation> annotation);
}

public interface ExecutableMethod<T, R> extends AnnotationMetadata {
    String getMethodName();
    Class<T> getDeclaringType();
    Class<R> getReturnType();
    Argument<?>[] getArguments();
    
    R invoke(T instance, Object... arguments);
    boolean isAbstract();
    boolean isStatic();
    boolean isPublic();
    boolean isPrivate();
    boolean isFinal();
}

public class IntrospectionException extends RuntimeException {
    public IntrospectionException(String message);
    public IntrospectionException(String message, Throwable cause);
}