java.lang.Object
- org.springframework.web.method.annotation.AbstractNamedValueMethodArgumentResolver

All Implemented Interfaces:
HandlerMethodArgumentResolver
Direct Known Subclasses:
AbstractCookieValueMethodArgumentResolver, ExpressionValueMethodArgumentResolver, MatrixVariableMethodArgumentResolver, PathVariableMethodArgumentResolver, RequestAttributeMethodArgumentResolver, RequestHeaderMethodArgumentResolver, RequestParamMethodArgumentResolver, SessionAttributeMethodArgumentResolver
```
public abstract class AbstractNamedValueMethodArgumentResolver
extends Object
implements HandlerMethodArgumentResolver
```
Abstract base class for resolving method arguments from a named value. Request parameters, request headers, and path variables are examples of named values. Each may have a name, a required flag, and a default value.
Subclasses define how to do the following:
- Obtain named value information for a method parameter
- Resolve names into argument values
- Handle missing argument values when argument values are required
- Optionally handle a resolved value
A default value string can contain ${...} placeholders and Spring Expression Language #{...} expressions. For this to work a ConfigurableBeanFactory must be supplied to the class constructor.
A WebDataBinder is created to apply type conversion to the resolved argument value if it doesn't match the method parameter type.
Since:
3.1
Author:
Arjen Poutsma, Rossen Stoyanchev, Juergen Hoeller

Nested Class Summary

Nested Classes
Modifier and Type	Class	Description
`protected static class`	`AbstractNamedValueMethodArgumentResolver.NamedValueInfo`	Represents the information about a named value, including name, whether it's required and a default value.

Constructor Summary

Constructors
Constructor	Description
`AbstractNamedValueMethodArgumentResolver()`
`AbstractNamedValueMethodArgumentResolver(ConfigurableBeanFactory beanFactory)`	Create a new `AbstractNamedValueMethodArgumentResolver` instance.

Method Summary

All Methods Instance Methods Abstract Methods Concrete Methods
Modifier and Type	Method	Description
`protected abstract AbstractNamedValueMethodArgumentResolver.NamedValueInfo`	`createNamedValueInfo(MethodParameter parameter)`	Create the `AbstractNamedValueMethodArgumentResolver.NamedValueInfo` object for the given method parameter.
`protected void`	`handleMissingValue(String name, MethodParameter parameter)`	Invoked when a named value is required, but `resolveName(String, MethodParameter, NativeWebRequest)` returned `null` and there is no default value.
`protected void`	`handleMissingValue(String name, MethodParameter parameter, NativeWebRequest request)`	Invoked when a named value is required, but `resolveName(String, MethodParameter, NativeWebRequest)` returned `null` and there is no default value.
`protected void`	`handleResolvedValue(Object arg, String name, MethodParameter parameter, ModelAndViewContainer mavContainer, NativeWebRequest webRequest)`	Invoked after a value is resolved.
`Object`	`resolveArgument(MethodParameter parameter, ModelAndViewContainer mavContainer, NativeWebRequest webRequest, WebDataBinderFactory binderFactory)`	Resolves a method parameter into an argument value from a given request.
`protected abstract Object`	`resolveName(String name, MethodParameter parameter, NativeWebRequest request)`	Resolve the given parameter type and value name into an argument value.

Methods inherited from class java.lang.Object
clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Methods inherited from interface org.springframework.web.method.support.HandlerMethodArgumentResolver
supportsParameter

- Constructor Detail
  - AbstractNamedValueMethodArgumentResolver
```
public AbstractNamedValueMethodArgumentResolver()
```
  - AbstractNamedValueMethodArgumentResolver
```
public AbstractNamedValueMethodArgumentResolver(@Nullable
                                                ConfigurableBeanFactory beanFactory)
```
    Create a new AbstractNamedValueMethodArgumentResolver instance.
    Parameters:
    beanFactory - a bean factory to use for resolving ${...} placeholder and #{...} SpEL expressions in default values, or null if default values are not expected to contain expressions
- Method Detail
  - resolveArgument
```
@Nullable
public final Object resolveArgument(MethodParameter parameter,
                                    @Nullable
                                    ModelAndViewContainer mavContainer,
                                    NativeWebRequest webRequest,
                                    @Nullable
                                    WebDataBinderFactory binderFactory)
                             throws Exception
```
    Description copied from interface: HandlerMethodArgumentResolver
    Resolves a method parameter into an argument value from a given request. A ModelAndViewContainer provides access to the model for the request. A WebDataBinderFactory provides a way to create a WebDataBinder instance when needed for data binding and type conversion purposes.
    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.
    mavContainer - the ModelAndViewContainer for the current request
    webRequest - the current request
    binderFactory - a factory for creating WebDataBinder instances
    Returns:
    the resolved argument value, or null if not resolvable
    Throws:
    Exception - in case of errors with the preparation of argument values
  - createNamedValueInfo
```
protected abstract AbstractNamedValueMethodArgumentResolver.NamedValueInfo createNamedValueInfo(MethodParameter parameter)
```
    Create the AbstractNamedValueMethodArgumentResolver.NamedValueInfo object for the given method parameter. Implementations typically retrieve the method annotation by means of MethodParameter.getParameterAnnotation(Class).
    Parameters:
    parameter - the method parameter
    Returns:
    the named value information
  - resolveName
```
@Nullable
protected abstract Object resolveName(String name,
                                      MethodParameter parameter,
                                      NativeWebRequest request)
                               throws Exception
```
    Resolve the given parameter type and value name into an argument value.
    Parameters:
    name - the name of the value being resolved
    parameter - the method parameter to resolve to an argument value (pre-nested in case of a Optional declaration)
    request - the current request
    Returns:
    the resolved argument (may be null)
    Throws:
    Exception - in case of errors
  - handleMissingValue
```
protected void handleMissingValue(String name,
                                  MethodParameter parameter,
                                  NativeWebRequest request)
                           throws Exception
```
    Invoked when a named value is required, but resolveName(String, MethodParameter, NativeWebRequest) returned null and there is no default value. Subclasses typically throw an exception in this case.
    Parameters:
    name - the name for the value
    parameter - the method parameter
    request - the current request
    Throws:
    Exception
    Since:
    4.3
  - handleMissingValue
```
protected void handleMissingValue(String name,
                                  MethodParameter parameter)
                           throws ServletException
```
    Invoked when a named value is required, but resolveName(String, MethodParameter, NativeWebRequest) returned null and there is no default value. Subclasses typically throw an exception in this case.
    Parameters:
    name - the name for the value
    parameter - the method parameter
    Throws:
    ServletException
  - handleResolvedValue
```
protected void handleResolvedValue(@Nullable
                                   Object arg,
                                   String name,
                                   MethodParameter parameter,
                                   @Nullable
                                   ModelAndViewContainer mavContainer,
                                   NativeWebRequest webRequest)
```
    Invoked after a value is resolved.
    Parameters:
    arg - the resolved argument value
    name - the argument name
    parameter - the argument parameter type
    mavContainer - the ModelAndViewContainer (may be null)
    webRequest - the current request

Class AbstractNamedValueMethodArgumentResolver

Nested Class Summary

Constructor Summary

Method Summary

Methods inherited from class java.lang.Object

Methods inherited from interface org.springframework.web.method.support.HandlerMethodArgumentResolver

Constructor Detail

AbstractNamedValueMethodArgumentResolver

AbstractNamedValueMethodArgumentResolver

Method Detail

resolveArgument

createNamedValueInfo

resolveName

handleMissingValue

handleMissingValue

handleResolvedValue