org.springframework.messaging.handler.invocation

Class AbstractMethodMessageHandler<T>

java.lang.Object

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

Type Parameters:

T - the type of the Object that contains information mapping a HandlerMethod to incoming messages

All Implemented Interfaces:

Aware, InitializingBean, ApplicationContextAware, MessageHandler

Direct Known Subclasses:

SimpAnnotationMethodMessageHandler

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

Abstract base class for 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:

4.0

Author:

Rossen Stoyanchev, Juergen Hoeller

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 a BeanFactory after it has set all bean properties supplied (and satisfied BeanFactoryAware and ApplicationContextAware).
protected abstract AbstractExceptionHandlerMethodResolver	createExceptionHandlerMethodResolverFor(Class<?> beanType)
protected HandlerMethod	createHandlerMethod(Object handler, Method method) Create a HandlerMethod instance from an Object handler that is either a handler instance or a String-based bean name.
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.
ApplicationContext	getApplicationContext()
List<HandlerMethodArgumentResolver>	getArgumentResolvers()
List<HandlerMethodArgumentResolver>	getCustomArgumentResolvers() Return the configured custom argument resolvers, if any.
List<HandlerMethodReturnValueHandler>	getCustomReturnValueHandlers() Return the configured custom return value handlers, if any.
protected abstract String	getDestination(Message<?> message)
Collection<String>	getDestinationPrefixes() Return the configured destination prefixes.
protected abstract Set<String>	getDirectLookupDestinations(T mapping) Return destinations contained in the mapping that are not patterns and are therefore suitable for direct lookups.
protected InvocableHandlerMethod	getExceptionHandlerMethod(HandlerMethod handlerMethod, Exception exception) Find an @MessageExceptionHandler method for the given exception.
Map<T,HandlerMethod>	getHandlerMethods() Return a map with all handler methods and their mappings.
protected String	getLookupDestination(String destination) Check whether the given destination (of an incoming message) matches to one of the configured destination prefixes and if so return the remaining portion of the destination after the matched prefix.
protected abstract Comparator<T>	getMappingComparator(Message<?> message) Return a comparator for sorting matching mappings.
protected abstract T	getMappingForMethod(Method method, Class<?> handlerType) Provide the mapping for a handler method.
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.
List<HandlerMethodReturnValueHandler>	getReturnValueHandlers()
protected void	handleMatch(T mapping, HandlerMethod handlerMethod, String lookupDestination, Message<?> message)
void	handleMessage(Message<?> message) Handle the given message.
protected void	handleMessageInternal(Message<?> message, String lookupDestination)
protected void	handleNoMatch(Set<T> ts, String lookupDestination, Message<?> message)
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 abstract boolean	isHandler(Class<?> beanType) Whether the given bean type should be introspected for messaging handling methods.
protected void	processHandlerMethodException(HandlerMethod handlerMethod, Exception ex, Message<?> message)
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	setArgumentResolvers(List<HandlerMethodArgumentResolver> argumentResolvers) Configure the complete list of supported argument types effectively overriding the ones configured by default.
void	setCustomArgumentResolvers(List<HandlerMethodArgumentResolver> customArgumentResolvers) Sets the list of custom HandlerMethodArgumentResolvers that will be used after resolvers for supported argument type.
void	setCustomReturnValueHandlers(List<HandlerMethodReturnValueHandler> customReturnValueHandlers) Set the list of custom HandlerMethodReturnValueHandlers that will be used after return value handlers for known types.
void	setDestinationPrefixes(Collection<String> prefixes) When this property is configured only messages to destinations matching one of the configured prefixes are eligible for handling.
void	setReturnValueHandlers(List<HandlerMethodReturnValueHandler> returnValueHandlers) Configure the complete list of supported return value types effectively overriding the ones configured by default.
String	toString()

Methods inherited from class java.lang.Object

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

Field Detail

logger

protected final Log logger

Constructor Detail

AbstractMethodMessageHandler

public AbstractMethodMessageHandler()

Method Detail

setDestinationPrefixes

public void setDestinationPrefixes(Collection<String> prefixes)

When this property is configured only messages to destinations matching one of the configured prefixes are eligible for handling. When there is a match the prefix is removed and only the remaining part of the destination is used for method-mapping purposes.

By default, no prefixes are configured in which case all messages are eligible for handling.

getDestinationPrefixes

public Collection<String> getDestinationPrefixes()

Return the configured destination prefixes.

setCustomArgumentResolvers

public void setCustomArgumentResolvers(List<HandlerMethodArgumentResolver> customArgumentResolvers)

Sets the list of custom HandlerMethodArgumentResolvers that will be used after resolvers for supported argument type.

Parameters:

customArgumentResolvers - the list of resolvers; never null.

getCustomArgumentResolvers

public List<HandlerMethodArgumentResolver> getCustomArgumentResolvers()

Return the configured custom argument resolvers, if any.

setCustomReturnValueHandlers

public void setCustomReturnValueHandlers(List<HandlerMethodReturnValueHandler> customReturnValueHandlers)

Set the list of custom HandlerMethodReturnValueHandlers that will be used after return value handlers for known types.

Parameters:

customReturnValueHandlers - the list of custom return value handlers, never null.

getCustomReturnValueHandlers

public List<HandlerMethodReturnValueHandler> getCustomReturnValueHandlers()

Return the configured custom return value handlers, if any.

setArgumentResolvers

public void setArgumentResolvers(List<HandlerMethodArgumentResolver> argumentResolvers)

Configure the complete list of supported argument types effectively overriding the ones configured by default. This is an advanced option. For most use cases it should be sufficient to use setCustomArgumentResolvers(java.util.List<org.springframework.messaging.handler.invocation.HandlerMethodArgumentResolver>).

getArgumentResolvers

public List<HandlerMethodArgumentResolver> getArgumentResolvers()

setReturnValueHandlers

public void setReturnValueHandlers(List<HandlerMethodReturnValueHandler> returnValueHandlers)

Configure the complete list of supported return value types effectively overriding the ones configured by default. This is an advanced option. For most use cases it should be sufficient to use setCustomReturnValueHandlers(java.util.List<org.springframework.messaging.handler.invocation.HandlerMethodReturnValueHandler>).

getReturnValueHandlers

public List<HandlerMethodReturnValueHandler> getReturnValueHandlers()

getHandlerMethods

public Map<T,HandlerMethod> getHandlerMethods()

Return a map with all handler methods and their mappings.

setApplicationContext

public void setApplicationContext(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

public ApplicationContext getApplicationContext()

afterPropertiesSet

public void afterPropertiesSet()

Description copied from interface: InitializingBean

Invoked by a BeanFactory after it has set all bean properties supplied (and satisfied BeanFactoryAware and ApplicationContextAware).

This method allows the bean instance to perform initialization only possible when all bean properties have been set and to throw an exception in the event of misconfiguration.

Specified by:

afterPropertiesSet in interface InitializingBean

initArgumentResolvers

protected abstract List<? extends HandlerMethodArgumentResolver> initArgumentResolvers()

Return the list of argument resolvers to use. Invoked only if the resolvers have not already been set via setArgumentResolvers(java.util.List<org.springframework.messaging.handler.invocation.HandlerMethodArgumentResolver>).

Subclasses should also take into account custom argument types configured via setCustomArgumentResolvers(java.util.List<org.springframework.messaging.handler.invocation.HandlerMethodArgumentResolver>).

initReturnValueHandlers

protected abstract List<? extends HandlerMethodReturnValueHandler> initReturnValueHandlers()

Return the list of return value handlers to use. Invoked only if the return value handlers have not already been set via setReturnValueHandlers(java.util.List<org.springframework.messaging.handler.invocation.HandlerMethodReturnValueHandler>).

Subclasses should also take into account custom return value types configured via setCustomReturnValueHandlers(java.util.List<org.springframework.messaging.handler.invocation.HandlerMethodReturnValueHandler>).

isHandler

protected abstract boolean isHandler(Class<?> beanType)

Whether the given bean type should be introspected for messaging handling methods.

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.

Parameters:

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

getMappingForMethod

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

Provide the mapping for a handler method.

Parameters:

method - the method to provide a mapping for

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

Register a handler method and its unique mapping.

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

createHandlerMethod

protected HandlerMethod createHandlerMethod(Object handler,
                                            Method method)

Create a HandlerMethod instance from an Object handler that is either a handler instance or a String-based bean name.

getDirectLookupDestinations

protected abstract Set<String> getDirectLookupDestinations(T mapping)

Return destinations contained in the mapping that are not patterns and are therefore suitable for direct lookups.

registerExceptionHandlerAdvice

protected void registerExceptionHandlerAdvice(MessagingAdviceBean bean,
                                              AbstractExceptionHandlerMethodResolver resolver)

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

Since:

4.2

handleMessage

public void handleMessage(Message<?> message)
                   throws MessagingException

Description copied from interface: MessageHandler

Handle the given message.

Specified by:

handleMessage in interface MessageHandler

Parameters:

message - the message to be handled

Throws:

MessagingException

getDestination

protected abstract String getDestination(Message<?> message)

getLookupDestination

protected String getLookupDestination(String destination)

Check whether the given destination (of an incoming message) matches to one of the configured destination prefixes and if so return the remaining portion of the destination after the matched prefix.

If there are no matching prefixes, return null.

If there are no destination prefixes, return the destination as is.

handleMessageInternal

protected void handleMessageInternal(Message<?> message,
                                     String lookupDestination)

getMatchingMapping

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

handleMatch

protected void handleMatch(T mapping,
                           HandlerMethod handlerMethod,
                           String lookupDestination,
                           Message<?> message)

processHandlerMethodException

protected void processHandlerMethodException(HandlerMethod handlerMethod,
                                             Exception ex,
                                             Message<?> message)

createExceptionHandlerMethodResolverFor

protected abstract AbstractExceptionHandlerMethodResolver createExceptionHandlerMethodResolverFor(Class<?> beanType)

getExceptionHandlerMethod

protected InvocableHandlerMethod getExceptionHandlerMethod(HandlerMethod handlerMethod,
                                                           Exception exception)

Find an @MessageExceptionHandler method for the given exception. The default implementation searches methods in the class hierarchy of the HandlerMethod first and if not found, it continues searching for additional @MessageExceptionHandler methods among the configured MessagingAdviceBean, if any.

Parameters:

handlerMethod - the method where the exception was raised

exception - the raised exception

Returns:

a method to handle the exception, or null

Since:

4.2

handleNoMatch

protected void handleNoMatch(Set<T> ts,
                             String lookupDestination,
                             Message<?> message)

toString

public String toString()

Overrides:

toString in class Object