org.springframework.messaging.handler.annotation.support

Class MessageMethodArgumentResolver

java.lang.Object

org.springframework.messaging.handler.annotation.support.MessageMethodArgumentResolver

All Implemented Interfaces:

HandlerMethodArgumentResolver

public class MessageMethodArgumentResolver
extends Object
implements HandlerMethodArgumentResolver

HandlerMethodArgumentResolver for Message method arguments. Validates that the generic type of the payload matches to the message value or otherwise applies MessageConverter to convert to the expected payload type.

Since:

4.0

Author:

Rossen Stoyanchev, Stephane Nicoll, Juergen Hoeller

Constructor Summary

Constructors

Constructor and Description
MessageMethodArgumentResolver() Create a default resolver instance without message conversion.
MessageMethodArgumentResolver(MessageConverter converter) Create a resolver instance with the given MessageConverter.

Method Summary

Modifier and Type	Method and Description
protected Class<?>	getPayloadType(MethodParameter parameter, Message<?> message) Resolve the target class to convert the payload to.
protected boolean	isEmptyPayload(Object payload) Check if the given payload is empty.
Object	resolveArgument(MethodParameter parameter, Message<?> message) Resolves a method parameter into an argument value from a given message.
boolean	supportsParameter(MethodParameter parameter) Whether the given method parameter is supported by this resolver.

Methods inherited from class java.lang.Object

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

Constructor Detail

MessageMethodArgumentResolver

public MessageMethodArgumentResolver()

Create a default resolver instance without message conversion.

MessageMethodArgumentResolver

public MessageMethodArgumentResolver(@Nullable
                                     MessageConverter converter)

Create a resolver instance with the given MessageConverter.

Parameters:

converter - the MessageConverter to use (may be null)

Since:

4.3

Method Detail

supportsParameter

public boolean supportsParameter(MethodParameter parameter)

Description copied from interface: HandlerMethodArgumentResolver

Whether the given method parameter is supported by this resolver.

Specified by:

supportsParameter in interface HandlerMethodArgumentResolver

Parameters:

parameter - the method parameter to check

Returns:

true if this resolver supports the supplied parameter; false otherwise

resolveArgument

public Object resolveArgument(MethodParameter parameter,
                              Message<?> message)
                       throws Exception

Description copied from interface: HandlerMethodArgumentResolver

Resolves a method parameter into an argument value from a given message.

Specified by:

resolveArgument in interface HandlerMethodArgumentResolver

Parameters:

parameter - the method parameter to resolve. This parameter must have previously been passed to HandlerMethodArgumentResolver.supportsParameter(org.springframework.core.MethodParameter) which must have returned true.

message - the currently processed message

Returns:

the resolved argument value, or null

Throws:

Exception - in case of errors with the preparation of argument values

getPayloadType

protected Class<?> getPayloadType(MethodParameter parameter,
                                  Message<?> message)

Resolve the target class to convert the payload to.

By default this is the generic type declared in the Message method parameter but that can be overridden to select a more specific target type after also taking into account the "Content-Type", e.g. return String if target type is Object and "Content-Type:text/**".

Parameters:

parameter - the target method parameter

message - the message being processed

Returns:

the target type to use

Since:

5.2

isEmptyPayload

protected boolean isEmptyPayload(@Nullable
                                 Object payload)

Check if the given payload is empty.

Parameters:

payload - the payload to check (can be null)