Java Code Examples for org.springframework.core.ResolvableType#resolve()

/**
 * Resolve variable resolvable type.
 *
 * @param typeVariable the type variable
 * @param contextType the context type
 * @return the resolvable type
 */
static ResolvableType resolveVariable(TypeVariable<?> typeVariable, ResolvableType contextType) {
	ResolvableType resolvedType;
	if (contextType.hasGenerics()) {
		resolvedType = ResolvableType.forType(typeVariable, contextType);
		if (resolvedType.resolve() != null) {
			return resolvedType;
		}
	}

	ResolvableType superType = contextType.getSuperType();
	if (superType != ResolvableType.NONE) {
		resolvedType = resolveVariable(typeVariable, superType);
		if (resolvedType.resolve() != null) {
			return resolvedType;
		}
	}
	for (ResolvableType ifc : contextType.getInterfaces()) {
		resolvedType = resolveVariable(typeVariable, ifc);
		if (resolvedType.resolve() != null) {
			return resolvedType;
		}
	}
	return ResolvableType.NONE;
}
 

@Nullable
protected ResolvableType getReturnTypeForFactoryMethod(RootBeanDefinition rbd, DependencyDescriptor descriptor) {
	// Should typically be set for any kind of factory method, since the BeanFactory
	// pre-resolves them before reaching out to the AutowireCandidateResolver...
	ResolvableType returnType = rbd.factoryMethodReturnType;
	if (returnType == null) {
		Method factoryMethod = rbd.getResolvedFactoryMethod();
		if (factoryMethod != null) {
			returnType = ResolvableType.forMethodReturnType(factoryMethod);
		}
	}
	if (returnType != null) {
		Class<?> resolvedClass = returnType.resolve();
		if (resolvedClass != null && descriptor.getDependencyType().isAssignableFrom(resolvedClass)) {
			// Only use factory method metadata if the return type is actually expressive enough
			// for our dependency. Otherwise, the returned instance type may have matched instead
			// in case of a singleton instance having been registered with the container already.
			return returnType;
		}
	}
	return null;
}
 

private ResolvableType resolveVariable(TypeVariable<?> typeVariable, ResolvableType contextType) {
	ResolvableType resolvedType;
	if (contextType.hasGenerics()) {
		resolvedType = ResolvableType.forType(typeVariable, contextType);
		if (resolvedType.resolve() != null) {
			return resolvedType;
		}
	}

	ResolvableType superType = contextType.getSuperType();
	if (superType != ResolvableType.NONE) {
		resolvedType = resolveVariable(typeVariable, superType);
		if (resolvedType.resolve() != null) {
			return resolvedType;
		}
	}
	for (ResolvableType ifc : contextType.getInterfaces()) {
		resolvedType = resolveVariable(typeVariable, ifc);
		if (resolvedType.resolve() != null) {
			return resolvedType;
		}
	}
	return ResolvableType.NONE;
}
 

@Override
public String[] getBeanNamesForType(@Nullable ResolvableType type) {
	boolean isFactoryType = false;
	if (type != null) {
		Class<?> resolved = type.resolve();
		if (resolved != null && FactoryBean.class.isAssignableFrom(resolved)) {
			isFactoryType = true;
		}
	}
	List<String> matches = new ArrayList<>();
	for (Map.Entry<String, Object> entry : this.beans.entrySet()) {
		String name = entry.getKey();
		Object beanInstance = entry.getValue();
		if (beanInstance instanceof FactoryBean && !isFactoryType) {
			Class<?> objectType = ((FactoryBean<?>) beanInstance).getObjectType();
			if (objectType != null && (type == null || type.isAssignableFrom(objectType))) {
				matches.add(name);
			}
		}
		else {
			if (type == null || type.isInstance(beanInstance)) {
				matches.add(name);
			}
		}
	}
	return StringUtils.toStringArray(matches);
}
 

@Override
@SuppressWarnings("unchecked")
public boolean supportsEventType(ResolvableType eventType) {
	if (this.delegate instanceof SmartApplicationListener) {
		Class<? extends ApplicationEvent> eventClass = (Class<? extends ApplicationEvent>) eventType.resolve();
		return (eventClass != null && ((SmartApplicationListener) this.delegate).supportsEventType(eventClass));
	}
	else {
		return (this.declaredEventType == null || this.declaredEventType.isAssignableFrom(eventType));
	}
}
 

@Override
public @Nonnull
String[] getBeanNamesForType(@Nonnull ResolvableType type) {
    final Class<?> resolved = type.resolve();
    if (resolved != null) {
        return getBeanNamesForType(resolved);
    }
    return StringUtils.EMPTY_STRING_ARRAY;
}
 

/**
 * {@inheritDoc}
 */
public void initialize(Object control, String property, InitializationConfig config) {
	if (this.dao == null) {
		log.warn("Nothing to do without persistent service");
		return;
	}
	Class<?> clazz = config.getType();
	PropertyDescriptor pd = PropertyUtils.getPropertyDescriptor(clazz, property);

	if (pd == null) {
		log.error("Not found property descriptor for property [" + property + "]") ;
		return;
	}
		
	ResolvableType propertyType = ResolvableType.forMethodReturnType(pd.getReadMethod());
	Annotation[] annotations = getAnnotations(property, clazz);
	for (Annotation a : annotations) {
		List<Object> items = null;
		
		if (ManyToOne.class.equals(a.annotationType()) || ManyToMany.class.equals(a.annotationType()) ) {
			items = getEntityList(propertyType, config.getSortPropertyName());
			
		}
		else if (Reference.class.equals(a.annotationType())) {
			Reference r = (Reference) a;
			Class<?> type = void.class.equals(r.target()) ? propertyType.resolve() : r.target();
			List<Object> entities = getEntityList(type, config.getSortPropertyName());
			items = StringUtils.isEmpty(r.property()) ?  entities : 
				getValueList(entities, r.property());	
		}
		
		if (items != null) {
			if (control instanceof AbstractSelect) {
				for (Object item : items) 
					((AbstractSelect) control).addItem(item);
			}
			break;
		}
	}
}
 

static Set<Object[]> getTestParameters(Set<ResolvableType> testClasses) {
    Set<Object[]> parameters = new HashSet<>();
    for (ResolvableType resolvableRawClass : testClasses) {
        Class<?> rawClass = resolvableRawClass.resolve();
        StringBuilder testName = new StringBuilder(rawClass.getSimpleName());
        for (ResolvableType resolvableGeneric : resolvableRawClass.getGenerics()) {
            Class<?> genericClass = resolvableGeneric.getRawClass();
            if (genericClass != null) testName = testName.append('—').append(genericClass.getSimpleName());
        }

        parameters.add(new Object[]{testName.toString(), rawClass});
    }
    return parameters;
}
 

@Override
public String[] getBeanNamesForType(@Nullable ResolvableType type) {
	boolean isFactoryType = false;
	if (type != null) {
		Class<?> resolved = type.resolve();
		if (resolved != null && FactoryBean.class.isAssignableFrom(resolved)) {
			isFactoryType = true;
		}
	}
	List<String> matches = new ArrayList<>();
	for (Map.Entry<String, Object> entry : this.beans.entrySet()) {
		String name = entry.getKey();
		Object beanInstance = entry.getValue();
		if (beanInstance instanceof FactoryBean && !isFactoryType) {
			Class<?> objectType = ((FactoryBean<?>) beanInstance).getObjectType();
			if (objectType != null && (type == null || type.isAssignableFrom(objectType))) {
				matches.add(name);
			}
		}
		else {
			if (type == null || type.isInstance(beanInstance)) {
				matches.add(name);
			}
		}
	}
	return StringUtils.toStringArray(matches);
}
 

public List<Vehicle> getVehicles() throws NoSuchFieldException {
    ResolvableType vehiclesType = ResolvableType.forField(getClass().getDeclaredField("vehicles"));
    System.out.println(vehiclesType);
    ResolvableType type = vehiclesType.getGeneric();
    System.out.println(type);
    Class<?> aClass = type.resolve();
    System.out.println(aClass);
    return this.vehicles;
}
 

/**
 * Return the target type of this bean definition, if known
 * (either specified in advance or resolved on first instantiation).
 * @since 3.2.2
 */
@Nullable
public Class<?> getTargetType() {
	if (this.resolvedTargetType != null) {
		return this.resolvedTargetType;
	}
	ResolvableType targetType = this.targetType;
	return (targetType != null ? targetType.resolve() : null);
}
 

@Override
public Mono<Object> readMono(
		ResolvableType elementType, ReactiveHttpInputMessage message, Map<String, Object> hints) {

	// We're ahead of String + "*/*"
	// Let's see if we can aggregate the output (lest we time out)...

	if (elementType.resolve() == String.class) {
		Flux<DataBuffer> body = message.getBody();
		return stringDecoder.decodeToMono(body, elementType, null, null).cast(Object.class);
	}

	return Mono.error(new UnsupportedOperationException(
			"ServerSentEventHttpMessageReader only supports reading stream of events as a Flux"));
}
 

private static TypeDescriptor getElementTypeDescriptor(
		TypeDescriptor typeDescriptor) {
	TypeDescriptor elementTypeDescriptor = typeDescriptor.getElementTypeDescriptor();
	// that means it's not a collection but it is iterable, gh-135
	if (elementTypeDescriptor == null
			&& Iterable.class.isAssignableFrom(typeDescriptor.getType())) {
		ResolvableType type = typeDescriptor.getResolvableType().as(Iterable.class)
				.getGeneric(0);
		if (type.resolve() == null) {
			return null;
		}
		return new TypeDescriptor(type, null, typeDescriptor.getAnnotations());
	}
	return elementTypeDescriptor;
}
 

@SuppressWarnings("unchecked")
private Flux<DataBuffer> encodeContent(
		@Nullable Object content, MethodParameter returnType, DataBufferFactory bufferFactory,
		@Nullable MimeType mimeType, Map<String, Object> hints) {

	ResolvableType returnValueType = ResolvableType.forMethodParameter(returnType);
	ReactiveAdapter adapter = getAdapterRegistry().getAdapter(returnValueType.resolve(), content);

	Publisher<?> publisher;
	ResolvableType elementType;
	if (adapter != null) {
		publisher = adapter.toPublisher(content);
		boolean isUnwrapped = KotlinDetector.isKotlinReflectPresent() &&
				KotlinDetector.isKotlinType(returnType.getContainingClass()) &&
				KotlinDelegate.isSuspend(returnType.getMethod()) &&
				!COROUTINES_FLOW_CLASS_NAME.equals(returnValueType.toClass().getName());
		ResolvableType genericType = isUnwrapped ? returnValueType : returnValueType.getGeneric();
		elementType = getElementType(adapter, genericType);
	}
	else {
		publisher = Mono.justOrEmpty(content);
		elementType = (returnValueType.toClass() == Object.class && content != null ?
				ResolvableType.forInstance(content) : returnValueType);
	}

	if (elementType.resolve() == void.class || elementType.resolve() == Void.class) {
		return Flux.from(publisher).cast(DataBuffer.class);
	}

	Encoder<?> encoder = getEncoder(elementType, mimeType);
	return Flux.from((Publisher) publisher).map(value ->
			encodeValue(value, elementType, encoder, bufferFactory, mimeType, hints));
}
 

private Mono<Object> decodeContent(MethodParameter parameter, Message<?> message,
		boolean isContentRequired, Flux<DataBuffer> content, MimeType mimeType) {

	ResolvableType targetType = ResolvableType.forMethodParameter(parameter);
	Class<?> resolvedType = targetType.resolve();
	ReactiveAdapter adapter = (resolvedType != null ? getAdapterRegistry().getAdapter(resolvedType) : null);
	ResolvableType elementType = (adapter != null ? targetType.getGeneric() : targetType);
	isContentRequired = isContentRequired || (adapter != null && !adapter.supportsEmpty());
	Consumer<Object> validator = getValidator(message, parameter);

	Map<String, Object> hints = Collections.emptyMap();

	for (Decoder<?> decoder : this.decoders) {
		if (decoder.canDecode(elementType, mimeType)) {
			if (adapter != null && adapter.isMultiValue()) {
				Flux<?> flux = content
						.map(buffer -> decoder.decode(buffer, elementType, mimeType, hints))
						.onErrorResume(ex -> Flux.error(handleReadError(parameter, message, ex)));
				if (isContentRequired) {
					flux = flux.switchIfEmpty(Flux.error(() -> handleMissingBody(parameter, message)));
				}
				if (validator != null) {
					flux = flux.doOnNext(validator);
				}
				return Mono.just(adapter.fromPublisher(flux));
			}
			else {
				// Single-value (with or without reactive type wrapper)
				Mono<?> mono = content.next()
						.map(buffer -> decoder.decode(buffer, elementType, mimeType, hints))
						.onErrorResume(ex -> Mono.error(handleReadError(parameter, message, ex)));
				if (isContentRequired) {
					mono = mono.switchIfEmpty(Mono.error(() -> handleMissingBody(parameter, message)));
				}
				if (validator != null) {
					mono = mono.doOnNext(validator);
				}
				return (adapter != null ? Mono.just(adapter.fromPublisher(mono)) : Mono.from(mono));
			}
		}
	}

	return Mono.error(new MethodArgumentResolutionException(
			message, parameter, "Cannot decode to [" + targetType + "]" + message));
}
 

@Override
public boolean canDecode(ResolvableType elementType, @Nullable MimeType mimeType) {
	return (elementType.resolve() == String.class && super.canDecode(elementType, mimeType));
}
 

/**
 * For a specific class that implements or extends a parameterized type, return the
 * parameter of that interface at a given position. For example, for this class:
 *
 * <pre> {@code
 * class MessageChannelBinder implements Binder<MessageChannel, ?, ?>
 * } </pre>
 *
 * <pre> {@code
 * getParameterType(MessageChannelBinder.class, Binder.class, 0);
 * } </pre>
 *
 * will return {@code Binder}
 * @param evaluatedClass the evaluated class
 * @param interfaceClass the parametrized interface
 * @param position the position
 * @return the parameter type if any
 * @throws IllegalStateException if the evaluated class does not implement the
 * interface or
 */
public static Class<?> getParameterType(Class<?> evaluatedClass,
		Class<?> interfaceClass, int position) {
	Class<?> bindableType = null;
	Assert.isTrue(interfaceClass.isInterface(),
			"'interfaceClass' must be an interface");
	if (!interfaceClass.isAssignableFrom(evaluatedClass)) {
		throw new IllegalStateException(
				evaluatedClass + " does not implement " + interfaceClass);
	}
	ResolvableType currentType = ResolvableType.forType(evaluatedClass);
	while (!Object.class.equals(currentType.getRawClass()) && bindableType == null) {
		ResolvableType[] interfaces = currentType.getInterfaces();
		ResolvableType resolvableType = null;
		for (ResolvableType interfaceType : interfaces) {
			if (interfaceClass.equals(interfaceType.getRawClass())) {
				resolvableType = interfaceType;
				break;
			}
		}
		if (resolvableType == null) {
			currentType = currentType.getSuperType();
		}
		else {
			ResolvableType[] generics = resolvableType.getGenerics();
			ResolvableType generic = generics[position];
			Class<?> resolvedParameter = generic.resolve();
			if (resolvedParameter != null) {
				bindableType = resolvedParameter;
			}
			else {
				bindableType = Object.class;
			}
		}
	}
	if (bindableType == null) {
		throw new IllegalStateException(
				"Cannot find parameter of " + evaluatedClass.getName() + " for "
						+ interfaceClass + " at position " + position);
	}
	return bindableType;
}
 

/**
 * Read the body from a method argument with {@link HttpMessageReader}.
 * @param bodyParam represents the element type for the body
 * @param actualParam the actual method argument type; possibly different
 * from {@code bodyParam}, e.g. for an {@code HttpEntity} argument
 * @param isBodyRequired true if the body is required
 * @param bindingContext the binding context to use
 * @param exchange the current exchange
 * @return a Mono with the value to use for the method argument
 * @since 5.0.2
 */
protected Mono<Object> readBody(MethodParameter bodyParam, @Nullable MethodParameter actualParam,
		boolean isBodyRequired, BindingContext bindingContext, ServerWebExchange exchange) {

	ResolvableType bodyType = ResolvableType.forMethodParameter(bodyParam);
	ResolvableType actualType = (actualParam != null ? ResolvableType.forMethodParameter(actualParam) : bodyType);
	Class<?> resolvedType = bodyType.resolve();
	ReactiveAdapter adapter = (resolvedType != null ? getAdapterRegistry().getAdapter(resolvedType) : null);
	ResolvableType elementType = (adapter != null ? bodyType.getGeneric() : bodyType);
	isBodyRequired = isBodyRequired || (adapter != null && !adapter.supportsEmpty());

	ServerHttpRequest request = exchange.getRequest();
	ServerHttpResponse response = exchange.getResponse();

	MediaType contentType = request.getHeaders().getContentType();
	MediaType mediaType = (contentType != null ? contentType : MediaType.APPLICATION_OCTET_STREAM);
	Object[] hints = extractValidationHints(bodyParam);

	if (mediaType.isCompatibleWith(MediaType.APPLICATION_FORM_URLENCODED)) {
		return Mono.error(new IllegalStateException(
				"In a WebFlux application, form data is accessed via ServerWebExchange.getFormData()."));
	}

	if (logger.isDebugEnabled()) {
		logger.debug(exchange.getLogPrefix() + (contentType != null ?
				"Content-Type:" + contentType :
				"No Content-Type, using " + MediaType.APPLICATION_OCTET_STREAM));
	}

	for (HttpMessageReader<?> reader : getMessageReaders()) {
		if (reader.canRead(elementType, mediaType)) {
			Map<String, Object> readHints = Hints.from(Hints.LOG_PREFIX_HINT, exchange.getLogPrefix());
			if (adapter != null && adapter.isMultiValue()) {
				if (logger.isDebugEnabled()) {
					logger.debug(exchange.getLogPrefix() + "0..N [" + elementType + "]");
				}
				Flux<?> flux = reader.read(actualType, elementType, request, response, readHints);
				flux = flux.onErrorResume(ex -> Flux.error(handleReadError(bodyParam, ex)));
				if (isBodyRequired) {
					flux = flux.switchIfEmpty(Flux.error(() -> handleMissingBody(bodyParam)));
				}
				if (hints != null) {
					flux = flux.doOnNext(target ->
							validate(target, hints, bodyParam, bindingContext, exchange));
				}
				return Mono.just(adapter.fromPublisher(flux));
			}
			else {
				// Single-value (with or without reactive type wrapper)
				if (logger.isDebugEnabled()) {
					logger.debug(exchange.getLogPrefix() + "0..1 [" + elementType + "]");
				}
				Mono<?> mono = reader.readMono(actualType, elementType, request, response, readHints);
				mono = mono.onErrorResume(ex -> Mono.error(handleReadError(bodyParam, ex)));
				if (isBodyRequired) {
					mono = mono.switchIfEmpty(Mono.error(() -> handleMissingBody(bodyParam)));
				}
				if (hints != null) {
					mono = mono.doOnNext(target ->
							validate(target, hints, bodyParam, bindingContext, exchange));
				}
				return (adapter != null ? Mono.just(adapter.fromPublisher(mono)) : Mono.from(mono));
			}
		}
	}

	// No compatible reader but body may be empty..

	HttpMethod method = request.getMethod();
	if (contentType == null && method != null && SUPPORTED_METHODS.contains(method)) {
		Flux<DataBuffer> body = request.getBody().doOnNext(buffer -> {
			DataBufferUtils.release(buffer);
			// Body not empty, back to 415..
			throw new UnsupportedMediaTypeStatusException(mediaType, this.supportedMediaTypes, elementType);
		});
		if (isBodyRequired) {
			body = body.switchIfEmpty(Mono.error(() -> handleMissingBody(bodyParam)));
		}
		return (adapter != null ? Mono.just(adapter.fromPublisher(body)) : Mono.from(body));
	}

	return Mono.error(new UnsupportedMediaTypeStatusException(mediaType, this.supportedMediaTypes, elementType));
}
 

/**
 * Read the body from a method argument with {@link HttpMessageReader}.
 * @param bodyParam represents the element type for the body
 * @param actualParam the actual method argument type; possibly different
 * from {@code bodyParam}, e.g. for an {@code HttpEntity} argument
 * @param isBodyRequired true if the body is required
 * @param bindingContext the binding context to use
 * @param exchange the current exchange
 * @return a Mono with the value to use for the method argument
 * @since 5.0.2
 */
protected Mono<Object> readBody(MethodParameter bodyParam, @Nullable MethodParameter actualParam,
		boolean isBodyRequired, BindingContext bindingContext, ServerWebExchange exchange) {

	ResolvableType bodyType = ResolvableType.forMethodParameter(bodyParam);
	ResolvableType actualType = (actualParam != null ? ResolvableType.forMethodParameter(actualParam) : bodyType);
	Class<?> resolvedType = bodyType.resolve();
	ReactiveAdapter adapter = (resolvedType != null ? getAdapterRegistry().getAdapter(resolvedType) : null);
	ResolvableType elementType = (adapter != null ? bodyType.getGeneric() : bodyType);
	isBodyRequired = isBodyRequired || (adapter != null && !adapter.supportsEmpty());

	ServerHttpRequest request = exchange.getRequest();
	ServerHttpResponse response = exchange.getResponse();

	MediaType contentType = request.getHeaders().getContentType();
	MediaType mediaType = (contentType != null ? contentType : MediaType.APPLICATION_OCTET_STREAM);
	Object[] hints = extractValidationHints(bodyParam);

	if (logger.isDebugEnabled()) {
		logger.debug(exchange.getLogPrefix() + (contentType != null ?
				"Content-Type:" + contentType :
				"No Content-Type, using " + MediaType.APPLICATION_OCTET_STREAM));
	}

	for (HttpMessageReader<?> reader : getMessageReaders()) {
		if (reader.canRead(elementType, mediaType)) {
			Map<String, Object> readHints = Hints.from(Hints.LOG_PREFIX_HINT, exchange.getLogPrefix());
			if (adapter != null && adapter.isMultiValue()) {
				if (logger.isDebugEnabled()) {
					logger.debug(exchange.getLogPrefix() + "0..N [" + elementType + "]");
				}
				Flux<?> flux = reader.read(actualType, elementType, request, response, readHints);
				flux = flux.onErrorResume(ex -> Flux.error(handleReadError(bodyParam, ex)));
				if (isBodyRequired) {
					flux = flux.switchIfEmpty(Flux.error(() -> handleMissingBody(bodyParam)));
				}
				if (hints != null) {
					flux = flux.doOnNext(target ->
							validate(target, hints, bodyParam, bindingContext, exchange));
				}
				return Mono.just(adapter.fromPublisher(flux));
			}
			else {
				// Single-value (with or without reactive type wrapper)
				if (logger.isDebugEnabled()) {
					logger.debug(exchange.getLogPrefix() + "0..1 [" + elementType + "]");
				}
				Mono<?> mono = reader.readMono(actualType, elementType, request, response, readHints);
				mono = mono.onErrorResume(ex -> Mono.error(handleReadError(bodyParam, ex)));
				if (isBodyRequired) {
					mono = mono.switchIfEmpty(Mono.error(() -> handleMissingBody(bodyParam)));
				}
				if (hints != null) {
					mono = mono.doOnNext(target ->
							validate(target, hints, bodyParam, bindingContext, exchange));
				}
				return (adapter != null ? Mono.just(adapter.fromPublisher(mono)) : Mono.from(mono));
			}
		}
	}

	// No compatible reader but body may be empty..

	HttpMethod method = request.getMethod();
	if (contentType == null && method != null && SUPPORTED_METHODS.contains(method)) {
		Flux<DataBuffer> body = request.getBody().doOnNext(o -> {
			// Body not empty, back to 415..
			throw new UnsupportedMediaTypeStatusException(mediaType, this.supportedMediaTypes, elementType);
		});
		if (isBodyRequired) {
			body = body.switchIfEmpty(Mono.error(() -> handleMissingBody(bodyParam)));
		}
		return (adapter != null ? Mono.just(adapter.fromPublisher(body)) : Mono.from(body));
	}

	return Mono.error(new UnsupportedMediaTypeStatusException(mediaType, this.supportedMediaTypes, elementType));
}
 

@SuppressWarnings("unchecked")
private <T> Flux<DataBuffer> encodePart(byte[] boundary, String name, T value) {
	MultipartHttpOutputMessage outputMessage = new MultipartHttpOutputMessage(this.bufferFactory, getCharset());
	HttpHeaders outputHeaders = outputMessage.getHeaders();

	T body;
	ResolvableType resolvableType = null;
	if (value instanceof HttpEntity) {
		HttpEntity<T> httpEntity = (HttpEntity<T>) value;
		outputHeaders.putAll(httpEntity.getHeaders());
		body = httpEntity.getBody();
		Assert.state(body != null, "MultipartHttpMessageWriter only supports HttpEntity with body");

		if (httpEntity instanceof MultipartBodyBuilder.PublisherEntity<?, ?>) {
			MultipartBodyBuilder.PublisherEntity<?, ?> publisherEntity =
					(MultipartBodyBuilder.PublisherEntity<?, ?>) httpEntity;
			resolvableType = publisherEntity.getResolvableType();
		}
	}
	else {
		body = value;
	}
	if (resolvableType == null) {
		resolvableType = ResolvableType.forClass(body.getClass());
	}

	if (!outputHeaders.containsKey(HttpHeaders.CONTENT_DISPOSITION)) {
		if (body instanceof Resource) {
			outputHeaders.setContentDispositionFormData(name, ((Resource) body).getFilename());
		}
		else if (resolvableType.resolve() == Resource.class) {
			body = (T) Mono.from((Publisher<?>) body).doOnNext(o -> outputHeaders
					.setContentDispositionFormData(name, ((Resource) o).getFilename()));
		}
		else {
			outputHeaders.setContentDispositionFormData(name, null);
		}
	}

	MediaType contentType = outputHeaders.getContentType();

	final ResolvableType finalBodyType = resolvableType;
	Optional<HttpMessageWriter<?>> writer = this.partWriters.stream()
			.filter(partWriter -> partWriter.canWrite(finalBodyType, contentType))
			.findFirst();

	if (!writer.isPresent()) {
		return Flux.error(new CodecException("No suitable writer found for part: " + name));
	}

	Publisher<T> bodyPublisher =
			body instanceof Publisher ? (Publisher<T>) body : Mono.just(body);

	// The writer will call MultipartHttpOutputMessage#write which doesn't actually write
	// but only stores the body Flux and returns Mono.empty().

	Mono<Void> partContentReady = ((HttpMessageWriter<T>) writer.get())
			.write(bodyPublisher, resolvableType, contentType, outputMessage, DEFAULT_HINTS);

	// After partContentReady, we can access the part content from MultipartHttpOutputMessage
	// and use it for writing to the actual request body

	Flux<DataBuffer> partContent = partContentReady.thenMany(Flux.defer(outputMessage::getBody));

	return Flux.concat(Mono.just(generateBoundaryLine(boundary)), partContent, Mono.just(generateNewLine()));
}