public class ModelAttributeMethodProcessor extends Object implements HandlerMethodArgumentResolver, HandlerMethodReturnValueHandler
@ModelAttribute
and handles
return values from methods annotated with @ModelAttribute
.
Model attributes are obtained from the model or if not found possibly
created with a default constructor if it is available. Once created, the
attributed is populated with request data via data binding and also
validation may be applied if the argument is annotated with
@javax.validation.Valid
.
When this handler is created with annotationNotRequired=true
,
any non-simple type argument and return value is regarded as a model
attribute with or without the presence of an @ModelAttribute
.
Constructor and Description |
---|
ModelAttributeMethodProcessor(boolean annotationNotRequired) |
Modifier and Type | Method and Description |
---|---|
protected void |
bindRequestParameters(WebDataBinder binder,
NativeWebRequest request)
Extension point to bind the request to the target object.
|
protected Object |
createAttribute(String attributeName,
MethodParameter parameter,
WebDataBinderFactory binderFactory,
NativeWebRequest request)
Extension point to create the model attribute if not found in the model.
|
void |
handleReturnValue(Object returnValue,
MethodParameter returnType,
ModelAndViewContainer mavContainer,
NativeWebRequest webRequest)
Add non-null return values to the
ModelAndViewContainer . |
protected boolean |
isBindExceptionRequired(WebDataBinder binder,
MethodParameter parameter)
Whether to raise a
BindException on validation errors. |
Object |
resolveArgument(MethodParameter parameter,
ModelAndViewContainer mavContainer,
NativeWebRequest request,
WebDataBinderFactory binderFactory)
Resolve the argument from the model or if not found instantiate it with
its default if it is available.
|
boolean |
supportsParameter(MethodParameter parameter)
Whether the given method parameter is
supported by this resolver.
|
boolean |
supportsReturnType(MethodParameter returnType)
Return
true if there is a method-level @ModelAttribute
or if it is a non-simple type when annotationNotRequired=true . |
protected void |
validateIfApplicable(WebDataBinder binder,
MethodParameter parameter)
Validate the model attribute if applicable.
|
protected Log logger
public ModelAttributeMethodProcessor(boolean annotationNotRequired)
annotationNotRequired
- if "true", non-simple method arguments and
return values are considered model attributes with or without a
@ModelAttribute
annotation.public boolean supportsParameter(MethodParameter parameter)
HandlerMethodArgumentResolver
supportsParameter
in interface HandlerMethodArgumentResolver
parameter
- the method parameter to checkModelAttribute
or in default resolution mode also if it is not a simple type.public final Object resolveArgument(MethodParameter parameter, ModelAndViewContainer mavContainer, NativeWebRequest request, WebDataBinderFactory binderFactory) throws Exception
@java.validation.Valid
is present on the argument.resolveArgument
in interface HandlerMethodArgumentResolver
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
.mavContainer
- the ModelAndViewContainer for the current requestrequest
- the current requestbinderFactory
- a factory for creating WebDataBinder
instancesnull
BindException
- if data binding and validation result in an error
and the next method parameter is not of type Errors
.Exception
- if WebDataBinder initialization fails.protected Object createAttribute(String attributeName, MethodParameter parameter, WebDataBinderFactory binderFactory, NativeWebRequest request) throws Exception
attributeName
- the name of the attribute, never null
parameter
- the method parameterbinderFactory
- for creating WebDataBinder instancerequest
- the current requestnull
Exception
protected void bindRequestParameters(WebDataBinder binder, NativeWebRequest request)
binder
- the data binder instance to use for the bindingrequest
- the current requestprotected void validateIfApplicable(WebDataBinder binder, MethodParameter parameter)
The default implementation checks for @javax.validation.Valid
.
binder
- the DataBinder to be usedparameter
- the method parameterprotected boolean isBindExceptionRequired(WebDataBinder binder, MethodParameter parameter)
BindException
on validation errors.binder
- the data binder used to perform data bindingparameter
- the method argumenttrue
if the next method argument is not of type Errors
.public boolean supportsReturnType(MethodParameter returnType)
true
if there is a method-level @ModelAttribute
or if it is a non-simple type when annotationNotRequired=true
.supportsReturnType
in interface HandlerMethodReturnValueHandler
returnType
- the method return type to checktrue
if this handler supports the supplied return type;
false
otherwisepublic void handleReturnValue(Object returnValue, MethodParameter returnType, ModelAndViewContainer mavContainer, NativeWebRequest webRequest) throws Exception
ModelAndViewContainer
.handleReturnValue
in interface HandlerMethodReturnValueHandler
returnValue
- the value returned from the handler methodreturnType
- the type of the return value. This type must have
previously been passed to HandlerMethodReturnValueHandler.supportsReturnType(org.springframework.core.MethodParameter)
which must
have returned true
.mavContainer
- the ModelAndViewContainer for the current requestwebRequest
- the current requestException
- if the return value handling results in an error