org.springframework.messaging.handler.annotation.support

Class PayloadMethodArgumentResolver

java.lang.Object

org.springframework.messaging.handler.annotation.support.PayloadMethodArgumentResolver

All Implemented Interfaces:

HandlerMethodArgumentResolver

Direct Known Subclasses:

PayloadArgumentResolver

public class PayloadMethodArgumentResolver
extends Object
implements HandlerMethodArgumentResolver

A resolver to extract and convert the payload of a message using a MessageConverter. It also validates the payload using a Validator if the argument is annotated with a Validation annotation.

This HandlerMethodArgumentResolver should be ordered last as it supports all types and does not require the Payload annotation.

Since:

5.2

Author:

Rossen Stoyanchev, Juergen Hoeller, Brian Clozel, Stephane Nicoll

Constructor Summary

Constructors

Constructor and Description
PayloadMethodArgumentResolver(MessageConverter messageConverter) Create a new PayloadArgumentResolver with the given MessageConverter.
PayloadMethodArgumentResolver(MessageConverter messageConverter, Validator validator) Create a new PayloadArgumentResolver with the given MessageConverter and Validator.
PayloadMethodArgumentResolver(MessageConverter messageConverter, Validator validator, boolean useDefaultResolution) Create a new PayloadArgumentResolver with the given MessageConverter and Validator.

Method Summary

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

Methods inherited from class java.lang.Object

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

Constructor Detail

PayloadMethodArgumentResolver

public PayloadMethodArgumentResolver(MessageConverter messageConverter)

Create a new PayloadArgumentResolver with the given MessageConverter.

Parameters:

messageConverter - the MessageConverter to use (required)

PayloadMethodArgumentResolver

public PayloadMethodArgumentResolver(MessageConverter messageConverter,
                                     @Nullable
                                     Validator validator)

Create a new PayloadArgumentResolver with the given MessageConverter and Validator.

Parameters:

messageConverter - the MessageConverter to use (required)

validator - the Validator to use (optional)

PayloadMethodArgumentResolver

public PayloadMethodArgumentResolver(MessageConverter messageConverter,
                                     @Nullable
                                     Validator validator,
                                     boolean useDefaultResolution)

Create a new PayloadArgumentResolver with the given MessageConverter and Validator.

Parameters:

messageConverter - the MessageConverter to use (required)

validator - the Validator to use (optional)

useDefaultResolution - if "true" (the default) this resolver supports all parameters; if "false" then only arguments with the @Payload annotation are supported.

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

@Nullable
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

isEmptyPayload

protected boolean isEmptyPayload(@Nullable
                                 Object payload)

Specify if the given payload is empty.

Parameters:

payload - the payload to check (can be null)

resolveTargetClass

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

Resolve the target class to convert the payload to.

By default this is simply MethodParameter.getParameterType() 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

validate

protected void validate(Message<?> message,
                        MethodParameter parameter,
                        Object target)

Validate the payload if applicable.

The default implementation checks for @javax.validation.Valid, Spring's Validated, and custom annotations whose name starts with "Valid".

Parameters:

message - the currently processed message

parameter - the method parameter

target - the target payload object

Throws:

MethodArgumentNotValidException - in case of binding errors