org.springframework.shell.support

Class AbstractArgumentMethodArgumentResolver

java.lang.Object

org.springframework.shell.support.AbstractArgumentMethodArgumentResolver

All Implemented Interfaces:

org.springframework.messaging.handler.invocation.HandlerMethodArgumentResolver

Direct Known Subclasses:

ArgumentHeaderMethodArgumentResolver, ShellOptionMethodArgumentResolver

public abstract class AbstractArgumentMethodArgumentResolver
extends Object
implements org.springframework.messaging.handler.invocation.HandlerMethodArgumentResolver

Abstract base class to resolve method arguments from a named value, e.g. message headers or destination variables. Named values could have one or more of a name, a required flag, and a default value.

Subclasses only need to define specific steps such as how to obtain named value details from a method parameter, how to resolve to argument values, or how to handle missing values.

A default value string can contain ${...} placeholders and Spring Expression Language #{...} expressions which will be resolved if a ConfigurableBeanFactory is supplied to the class constructor.

A ConversionService is used to convert a resolved String argument value to the expected target method parameter type.

Author:

Janne Valkealahti

Nested Class Summary

Nested Classes

Modifier and Type	Class and Description
protected static class	AbstractArgumentMethodArgumentResolver.NamedValueInfo Represents a named value declaration.

Field Summary

Fields

Modifier and Type	Field and Description
static String	ARGUMENT_PREFIX

Constructor Summary

Constructors

Modifier	Constructor and Description
protected	AbstractArgumentMethodArgumentResolver(org.springframework.core.convert.ConversionService conversionService, org.springframework.beans.factory.config.ConfigurableBeanFactory beanFactory) Constructor with a ConversionService and a BeanFactory.

Method Summary

Modifier and Type	Method and Description
protected abstract AbstractArgumentMethodArgumentResolver.NamedValueInfo	createNamedValueInfo(org.springframework.core.MethodParameter parameter) Create the AbstractArgumentMethodArgumentResolver.NamedValueInfo object for the given method parameter.
protected abstract void	handleMissingValue(List<String> names, org.springframework.core.MethodParameter parameter, org.springframework.messaging.Message<?> message) Invoked when a value is required, but resolveArgumentInternal(org.springframework.core.MethodParameter, org.springframework.messaging.Message<?>, java.util.List<java.lang.String>) returned null and there is no default value.
protected void	handleResolvedValue(Object arg, List<String> name, org.springframework.core.MethodParameter parameter, org.springframework.messaging.Message<?> message) Invoked after a value is resolved.
Object	resolveArgument(org.springframework.core.MethodParameter parameter, org.springframework.messaging.Message<?> message)
protected abstract Object	resolveArgumentInternal(org.springframework.core.MethodParameter parameter, org.springframework.messaging.Message<?> message, List<String> names) Resolves 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.messaging.handler.invocation.HandlerMethodArgumentResolver

supportsParameter

Field Detail

ARGUMENT_PREFIX

public static final String ARGUMENT_PREFIX

See Also:

Constant Field Values

Constructor Detail

AbstractArgumentMethodArgumentResolver

protected AbstractArgumentMethodArgumentResolver(org.springframework.core.convert.ConversionService conversionService,
                                                 @Nullable
                                                 org.springframework.beans.factory.config.ConfigurableBeanFactory beanFactory)

Constructor with a ConversionService and a BeanFactory.

Parameters:

conversionService - conversion service for converting String values to the target method parameter type

beanFactory - a bean factory for resolving ${...} placeholders and #{...} SpEL expressions in default values

Method Detail

resolveArgument

public Object resolveArgument(org.springframework.core.MethodParameter parameter,
                              org.springframework.messaging.Message<?> message)
                       throws Exception

Specified by:

resolveArgument in interface org.springframework.messaging.handler.invocation.HandlerMethodArgumentResolver

Throws:

Exception

createNamedValueInfo

protected abstract AbstractArgumentMethodArgumentResolver.NamedValueInfo createNamedValueInfo(org.springframework.core.MethodParameter parameter)

Create the AbstractArgumentMethodArgumentResolver.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

resolveArgumentInternal

@Nullable
protected abstract Object resolveArgumentInternal(org.springframework.core.MethodParameter parameter,
                                                            org.springframework.messaging.Message<?> message,
                                                            List<String> names)
                                                     throws Exception

Resolves the given parameter type and value name into an argument value.

Parameters:

parameter - the method parameter to resolve to an argument value

message - the current request

name - the name of the value being resolved

Returns:

the resolved argument. May be null

Throws:

Exception - in case of errors

handleMissingValue

protected abstract void handleMissingValue(List<String> names,
                                           org.springframework.core.MethodParameter parameter,
                                           org.springframework.messaging.Message<?> message)

Invoked when a value is required, but resolveArgumentInternal(org.springframework.core.MethodParameter, org.springframework.messaging.Message<?>, java.util.List<java.lang.String>) returned null and there is no default value. Sub-classes can throw an appropriate exception for this case.

Parameters:

names - the name for the value

parameter - the target method parameter

message - the message being processed

handleResolvedValue

protected void handleResolvedValue(@Nullable
                                   Object arg,
                                   List<String> name,
                                   org.springframework.core.MethodParameter parameter,
                                   org.springframework.messaging.Message<?> message)

Invoked after a value is resolved.

Parameters:

arg - the resolved argument value

name - the argument name

parameter - the argument parameter type

message - the message