org.springframework.messaging.handler.invocation.reactive

Class AbstractMethodMessageHandler<T>

java.lang.Object

org.springframework.messaging.handler.invocation.reactive.AbstractMethodMessageHandler<T>

Type Parameters:

T - the type of the Object that contains information mapping information

All Implemented Interfaces:

Aware, BeanNameAware, InitializingBean, ApplicationContextAware, ReactiveMessageHandler

Direct Known Subclasses:

MessageMappingMessageHandler

public abstract class AbstractMethodMessageHandler<T>
extends Object
implements ReactiveMessageHandler, ApplicationContextAware, InitializingBean, BeanNameAware

Abstract base class for reactive HandlerMethod-based message handling. Provides most of the logic required to discover handler methods at startup, find a matching handler method at runtime for a given message and invoke it.

Also supports discovering and invoking exception handling methods to process exceptions raised during message handling.

Since:

5.2

Author:

Rossen Stoyanchev

Field Summary

Fields

Modifier and Type	Field and Description
protected Log	logger

Constructor Summary

Constructors

Constructor and Description
AbstractMethodMessageHandler()

Method Summary

Modifier and Type	Method and Description
void	afterPropertiesSet() Invoked by the containing BeanFactory after it has set all bean properties and satisfied BeanFactoryAware, ApplicationContextAware etc.
protected abstract AbstractExceptionHandlerMethodResolver	createExceptionMethodResolverFor(Class<?> beanType) Create a concrete instance of AbstractExceptionHandlerMethodResolver that finds exception handling methods based on some criteria, e.g.
protected void	detectHandlerMethods(Object handler) Detect if the given handler has any methods that can handle messages and if so register it with the extracted mapping information.
protected T	extendMapping(T mapping, HandlerMethod handlerMethod) This method is invoked just before mappings are added.
ApplicationContext	getApplicationContext()
ArgumentResolverConfigurer	getArgumentResolverConfigurer() Return the configured custom resolvers for handler method arguments.
protected HandlerMethodArgumentResolverComposite	getArgumentResolvers() Return the argument resolvers initialized during afterPropertiesSet().
String	getBeanName()
protected abstract RouteMatcher.Route	getDestination(Message<?> message) Extract the destination from the given message.
MultiValueMap<String,T>	getDestinationLookup() Return a read-only multi-value map with a direct lookup of mappings, (e.g.
protected abstract Set<String>	getDirectLookupMappings(T mapping) Return String-based destinations for the given mapping, if any, that can be used to find matches with a direct lookup (i.e.
Map<T,HandlerMethod>	getHandlerMethods() Return a read-only map with all handler methods and their mappings.
Predicate<Class<?>>	getHandlerPredicate() Return the configured handler predicate.
protected abstract Comparator<T>	getMappingComparator(Message<?> message) Return a comparator for sorting matching mappings.
protected abstract T	getMappingForMethod(Method method, Class<?> handlerType) Obtain the mapping for the given method, if any.
protected abstract T	getMatchingMapping(T mapping, Message<?> message) Check if a mapping matches the current message and return a possibly new mapping with conditions relevant to the current request.
ReactiveAdapterRegistry	getReactiveAdapterRegistry() Return the configured registry for adapting reactive types.
ReturnValueHandlerConfigurer	getReturnValueHandlerConfigurer() Return the configured return value handlers.
protected reactor.core.publisher.Mono<Void>	handleMatch(T mapping, HandlerMethod handlerMethod, Message<?> message)
reactor.core.publisher.Mono<Void>	handleMessage(Message<?> message) Handle the given message.
protected void	handleNoMatch(RouteMatcher.Route destination, Message<?> message) Invoked when no matching handler is found.
protected abstract List<? extends HandlerMethodArgumentResolver>	initArgumentResolvers() Return the list of argument resolvers to use.
protected abstract List<? extends HandlerMethodReturnValueHandler>	initReturnValueHandlers() Return the list of return value handlers to use.
protected void	registerExceptionHandlerAdvice(MessagingAdviceBean bean, AbstractExceptionHandlerMethodResolver resolver) Subclasses can invoke this method to populate the MessagingAdviceBean cache (e.g.
protected void	registerHandlerMethod(Object handler, Method method, T mapping) Register a handler method and its unique mapping.
void	setApplicationContext(ApplicationContext applicationContext) Set the ApplicationContext that this object runs in.
void	setArgumentResolverConfigurer(ArgumentResolverConfigurer configurer) Configure custom resolvers for handler method arguments.
void	setBeanName(String name) Set the name of the bean in the bean factory that created this bean.
void	setHandlerPredicate(Predicate<Class<?>> handlerPredicate) Configure a predicate for selecting which Spring beans to check for the presence of message handler methods.
void	setHandlers(List<Object> handlers) Manually configure the handlers to check for the presence of message handling methods, which also disables auto-detection via a handlerPredicate.
void	setReactiveAdapterRegistry(ReactiveAdapterRegistry registry) Configure the registry for adapting various reactive types.
void	setReturnValueHandlerConfigurer(ReturnValueHandlerConfigurer configurer) Configure custom return value handlers for handler methods.

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Field Detail

logger

protected final Log logger

Constructor Detail

AbstractMethodMessageHandler

public AbstractMethodMessageHandler()

Method Detail

setHandlerPredicate

public void setHandlerPredicate(@Nullable
                                Predicate<Class<?>> handlerPredicate)

Configure a predicate for selecting which Spring beans to check for the presence of message handler methods.

This is not set by default. However sub-classes may initialize it to some default strategy (e.g. @Controller classes).

See Also:

setHandlers(List)

getHandlerPredicate

@Nullable
public Predicate<Class<?>> getHandlerPredicate()

Return the configured handler predicate.

setHandlers

public void setHandlers(List<Object> handlers)

Manually configure the handlers to check for the presence of message handling methods, which also disables auto-detection via a handlerPredicate. If you do not want to disable auto-detection, then call this method first, and then set the handler predicate.

Parameters:

handlers - the handlers to check

setArgumentResolverConfigurer

public void setArgumentResolverConfigurer(ArgumentResolverConfigurer configurer)

Configure custom resolvers for handler method arguments.

getArgumentResolverConfigurer

public ArgumentResolverConfigurer getArgumentResolverConfigurer()

Return the configured custom resolvers for handler method arguments.

setReturnValueHandlerConfigurer

public void setReturnValueHandlerConfigurer(ReturnValueHandlerConfigurer configurer)

Configure custom return value handlers for handler methods.

getReturnValueHandlerConfigurer

public ReturnValueHandlerConfigurer getReturnValueHandlerConfigurer()

Return the configured return value handlers.

setReactiveAdapterRegistry

public void setReactiveAdapterRegistry(ReactiveAdapterRegistry registry)

Configure the registry for adapting various reactive types.

By default this is an instance of ReactiveAdapterRegistry with default settings.

getReactiveAdapterRegistry

public ReactiveAdapterRegistry getReactiveAdapterRegistry()

Return the configured registry for adapting reactive types.

setApplicationContext

public void setApplicationContext(@Nullable
                                  ApplicationContext applicationContext)

Description copied from interface: ApplicationContextAware

Set the ApplicationContext that this object runs in. Normally this call will be used to initialize the object.

Invoked after population of normal bean properties but before an init callback such as InitializingBean.afterPropertiesSet() or a custom init-method. Invoked after ResourceLoaderAware.setResourceLoader(org.springframework.core.io.ResourceLoader), ApplicationEventPublisherAware.setApplicationEventPublisher(org.springframework.context.ApplicationEventPublisher) and MessageSourceAware, if applicable.

Specified by:

setApplicationContext in interface ApplicationContextAware

Parameters:

applicationContext - the ApplicationContext object to be used by this object

See Also:

BeanInitializationException

getApplicationContext

@Nullable
public ApplicationContext getApplicationContext()

setBeanName

public void setBeanName(String name)

Description copied from interface: BeanNameAware

Set the name of the bean in the bean factory that created this bean.

Invoked after population of normal bean properties but before an init callback such as InitializingBean.afterPropertiesSet() or a custom init-method.

Specified by:

setBeanName in interface BeanNameAware

Parameters:

name - the name of the bean in the factory. Note that this name is the actual bean name used in the factory, which may differ from the originally specified name: in particular for inner bean names, the actual bean name might have been made unique through appending "#..." suffixes. Use the BeanFactoryUtils.originalBeanName(String) method to extract the original bean name (without suffix), if desired.

getBeanName

public String getBeanName()

registerExceptionHandlerAdvice

protected void registerExceptionHandlerAdvice(MessagingAdviceBean bean,
                                              AbstractExceptionHandlerMethodResolver resolver)

Subclasses can invoke this method to populate the MessagingAdviceBean cache (e.g. to support "global" @MessageExceptionHandler).

getHandlerMethods

public Map<T,HandlerMethod> getHandlerMethods()

Return a read-only map with all handler methods and their mappings.

getDestinationLookup

public MultiValueMap<String,T> getDestinationLookup()

Return a read-only multi-value map with a direct lookup of mappings, (e.g. for non-pattern destinations).

getArgumentResolvers

protected HandlerMethodArgumentResolverComposite getArgumentResolvers()

Return the argument resolvers initialized during afterPropertiesSet(). Primarily for internal use in sub-classes.

Since:

5.2.2

afterPropertiesSet

public void afterPropertiesSet()

Description copied from interface: InitializingBean

Invoked by the containing BeanFactory after it has set all bean properties and satisfied BeanFactoryAware, ApplicationContextAware etc.

This method allows the bean instance to perform validation of its overall configuration and final initialization when all bean properties have been set.

Specified by:

afterPropertiesSet in interface InitializingBean

initArgumentResolvers

protected abstract List<? extends HandlerMethodArgumentResolver> initArgumentResolvers()

Return the list of argument resolvers to use.

Subclasses should also take into account custom argument types configured via setArgumentResolverConfigurer(org.springframework.messaging.handler.invocation.reactive.ArgumentResolverConfigurer).

initReturnValueHandlers

protected abstract List<? extends HandlerMethodReturnValueHandler> initReturnValueHandlers()

Return the list of return value handlers to use.

Subclasses should also take into account custom return value types configured via setReturnValueHandlerConfigurer(org.springframework.messaging.handler.invocation.reactive.ReturnValueHandlerConfigurer).

detectHandlerMethods

protected final void detectHandlerMethods(Object handler)

Detect if the given handler has any methods that can handle messages and if so register it with the extracted mapping information.

Note: This method is protected and can be invoked by subclasses, but this should be done on startup only as documented in registerHandlerMethod(java.lang.Object, java.lang.reflect.Method, T).

Parameters:

handler - the handler to check, either an instance of a Spring bean name

getMappingForMethod

@Nullable
protected abstract T getMappingForMethod(Method method,
                                                   Class<?> handlerType)

Obtain the mapping for the given method, if any.

Parameters:

method - the method to check

handlerType - the handler type, possibly a sub-type of the method's declaring class

Returns:

the mapping, or null if the method is not mapped

registerHandlerMethod

protected final void registerHandlerMethod(Object handler,
                                           Method method,
                                           T mapping)

Register a handler method and its unique mapping.

Note: This method is protected and can be invoked by subclasses. Keep in mind however that the registration is not protected for concurrent use, and is expected to be done on startup.

Parameters:

handler - the bean name of the handler or the handler instance

method - the method to register

mapping - the mapping conditions associated with the handler method

Throws:

IllegalStateException - if another method was already registered under the same mapping

extendMapping

protected T extendMapping(T mapping,
                          HandlerMethod handlerMethod)

This method is invoked just before mappings are added. It allows sub-classes to update the mapping with the HandlerMethod in mind. This can be useful when the method signature is used to refine the mapping, e.g. based on the cardinality of input and output.

By default this method returns the mapping that is passed in.

Parameters:

mapping - the mapping to be added

handlerMethod - the target handler for the mapping

Returns:

a new mapping or the same

Since:

5.2.2

getDirectLookupMappings

protected abstract Set<String> getDirectLookupMappings(T mapping)

Return String-based destinations for the given mapping, if any, that can be used to find matches with a direct lookup (i.e. non-patterns).

Note: This is completely optional. The mapping metadata for a subclass may support neither direct lookups, nor String based destinations.

handleMessage

public reactor.core.publisher.Mono<Void> handleMessage(Message<?> message)
                                                throws MessagingException

Description copied from interface: ReactiveMessageHandler

Handle the given message.

Specified by:

handleMessage in interface ReactiveMessageHandler

Parameters:

message - the message to be handled

Returns:

a completion Mono for the result of the message handling

Throws:

MessagingException

handleMatch

protected reactor.core.publisher.Mono<Void> handleMatch(T mapping,
                                                        HandlerMethod handlerMethod,
                                                        Message<?> message)

getDestination

@Nullable
protected abstract RouteMatcher.Route getDestination(Message<?> message)

Extract the destination from the given message.

See Also:

getDirectLookupMappings(Object)

getMatchingMapping

@Nullable
protected abstract T getMatchingMapping(T mapping,
                                                  Message<?> message)

Check if a mapping matches the current message and return a possibly new mapping with conditions relevant to the current request.

Parameters:

mapping - the mapping to get a match for

message - the message being handled

Returns:

the match or null if there is no match

getMappingComparator

protected abstract Comparator<T> getMappingComparator(Message<?> message)

Return a comparator for sorting matching mappings. The returned comparator should sort 'better' matches higher.

Parameters:

message - the current Message

Returns:

the comparator, never null

handleNoMatch

protected void handleNoMatch(@Nullable
                             RouteMatcher.Route destination,
                             Message<?> message)

Invoked when no matching handler is found.

Parameters:

destination - the destination

message - the message

createExceptionMethodResolverFor

protected abstract AbstractExceptionHandlerMethodResolver createExceptionMethodResolverFor(Class<?> beanType)

Create a concrete instance of AbstractExceptionHandlerMethodResolver that finds exception handling methods based on some criteria, e.g. based on the presence of @MessageExceptionHandler.

Parameters:

beanType - the class in which an exception occurred during handling

Returns:

the resolver to use