java.lang.Object
- org.springframework.web.reactive.result.method.HandlerMethodArgumentResolverSupport
- - org.springframework.web.reactive.result.method.annotation.AbstractNamedValueArgumentResolver

All Implemented Interfaces:
HandlerMethodArgumentResolver
Direct Known Subclasses:
AbstractNamedValueSyncArgumentResolver, SessionAttributeMethodArgumentResolver
```
public abstract class AbstractNamedValueArgumentResolver
extends HandlerMethodArgumentResolverSupport
```
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.
Since:
5.0
Author:
Rossen Stoyanchev

Nested Class Summary

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

Field Summary
- Fields inherited from class org.springframework.web.reactive.result.method.HandlerMethodArgumentResolverSupport
  logger

Constructor Summary
Constructors
Constructor Description
AbstractNamedValueArgumentResolver(ConfigurableBeanFactory factory, ReactiveAdapterRegistry registry)
Create a new AbstractNamedValueArgumentResolver instance.

Method Summary

All Methods Instance Methods Abstract Methods Concrete Methods
Modifier and Type	Method	Description
`protected abstract AbstractNamedValueArgumentResolver.NamedValueInfo`	`createNamedValueInfo(MethodParameter parameter)`	Create the `AbstractNamedValueArgumentResolver.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, ServerWebExchange)` returned `null` and there is no default value.
`protected void`	`handleMissingValue(String name, MethodParameter parameter, ServerWebExchange exchange)`	Invoked when a named value is required, but `resolveName(String, MethodParameter, ServerWebExchange)` returned `null` and there is no default value.
`protected void`	`handleResolvedValue(Object arg, String name, MethodParameter parameter, Model model, ServerWebExchange exchange)`	Invoked after a value is resolved.
`reactor.core.publisher.Mono<Object>`	`resolveArgument(MethodParameter parameter, BindingContext bindingContext, ServerWebExchange exchange)`	Resolve the value for the method parameter.
`protected abstract reactor.core.publisher.Mono<Object>`	`resolveName(String name, MethodParameter parameter, ServerWebExchange exchange)`	Resolve the given parameter type and value name into an argument value.

Methods inherited from class org.springframework.web.reactive.result.method.HandlerMethodArgumentResolverSupport
checkAnnotatedParamNoReactiveWrapper, checkParameterType, checkParameterTypeNoReactiveWrapper, getAdapterRegistry

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.reactive.result.method.HandlerMethodArgumentResolver
supportsParameter

Constructor Detail
- AbstractNamedValueArgumentResolver
```
public AbstractNamedValueArgumentResolver(@Nullable
                                          ConfigurableBeanFactory factory,
                                          ReactiveAdapterRegistry registry)
```
  Create a new AbstractNamedValueArgumentResolver instance.
  Parameters:
  factory - 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
  registry - for checking reactive type wrappers

Method Detail

resolveArgument

public reactor.core.publisher.Mono<Object> resolveArgument(MethodParameter parameter,
                                                           BindingContext bindingContext,
                                                           ServerWebExchange exchange)

Description copied from interface: HandlerMethodArgumentResolver

Resolve the value for the method parameter.

Parameters:: parameter - the method parameter; bindingContext - the binding context to use; exchange - the current exchange
Returns:: Mono for the argument value, possibly empty

createNamedValueInfo
```
protected abstract AbstractNamedValueArgumentResolver.NamedValueInfo createNamedValueInfo(MethodParameter parameter)
```
Create the AbstractNamedValueArgumentResolver.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

protected abstract reactor.core.publisher.Mono<Object> resolveName(String name,
                                                                   MethodParameter parameter,
                                                                   ServerWebExchange exchange)

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); exchange - the current exchange
Returns:: the resolved argument (may be empty Mono)

handleMissingValue
```
protected void handleMissingValue(String name,
                                  MethodParameter parameter,
                                  ServerWebExchange exchange)
```
Invoked when a named value is required, but resolveName(String, MethodParameter, ServerWebExchange) 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
exchange - the current exchange

handleMissingValue
```
protected void handleMissingValue(String name,
                                  MethodParameter parameter)
```
Invoked when a named value is required, but resolveName(String, MethodParameter, ServerWebExchange) 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

handleResolvedValue

protected void handleResolvedValue(@Nullable
                                   Object arg,
                                   String name,
                                   MethodParameter parameter,
                                   Model model,
                                   ServerWebExchange exchange)

Invoked after a value is resolved.

Parameters:: arg - the resolved argument value; name - the argument name; parameter - the argument parameter type; model - the model; exchange - the current exchange

Class AbstractNamedValueArgumentResolver

Nested Class Summary

Field Summary

Fields inherited from class org.springframework.web.reactive.result.method.HandlerMethodArgumentResolverSupport

Constructor Summary

Method Summary

Methods inherited from class org.springframework.web.reactive.result.method.HandlerMethodArgumentResolverSupport

Methods inherited from class java.lang.Object

Methods inherited from interface org.springframework.web.reactive.result.method.HandlerMethodArgumentResolver

Constructor Detail

AbstractNamedValueArgumentResolver

Method Detail

resolveArgument

createNamedValueInfo

resolveName

handleMissingValue

handleMissingValue

handleResolvedValue