org.springframework.beans.factory.annotation

Class QualifierAnnotationAutowireCandidateResolver

java.lang.Object

org.springframework.beans.factory.support.SimpleAutowireCandidateResolver

org.springframework.beans.factory.support.GenericTypeAwareAutowireCandidateResolver

org.springframework.beans.factory.annotation.QualifierAnnotationAutowireCandidateResolver

All Implemented Interfaces:

Aware, BeanFactoryAware, AutowireCandidateResolver

Direct Known Subclasses:

ContextAnnotationAutowireCandidateResolver

public class QualifierAnnotationAutowireCandidateResolver
extends GenericTypeAwareAutowireCandidateResolver

AutowireCandidateResolver implementation that matches bean definition qualifiers against qualifier annotations on the field or parameter to be autowired. Also supports suggested expression values through a value annotation.

Also supports JSR-330's Qualifier annotation, if available.

Since:

2.5

Author:

Mark Fisher, Juergen Hoeller, Stephane Nicoll

See Also:

AutowireCandidateQualifier, Qualifier, Value

Constructor Summary

Constructors

Constructor and Description
QualifierAnnotationAutowireCandidateResolver() Create a new QualifierAnnotationAutowireCandidateResolver for Spring's standard Qualifier annotation.
QualifierAnnotationAutowireCandidateResolver(Class<? extends Annotation> qualifierType) Create a new QualifierAnnotationAutowireCandidateResolver for the given qualifier annotation type.
QualifierAnnotationAutowireCandidateResolver(Set<Class<? extends Annotation>> qualifierTypes) Create a new QualifierAnnotationAutowireCandidateResolver for the given qualifier annotation types.

Method Summary

Modifier and Type	Method and Description
void	addQualifierType(Class<? extends Annotation> qualifierType) Register the given type to be used as a qualifier when autowiring.
protected boolean	checkQualifier(BeanDefinitionHolder bdHolder, Annotation annotation, TypeConverter typeConverter) Match the given qualifier annotation against the candidate bean definition.
protected boolean	checkQualifiers(BeanDefinitionHolder bdHolder, Annotation[] annotationsToSearch) Match the given qualifier annotations against the candidate bean definition.
protected Object	extractValue(AnnotationAttributes attr) Extract the value attribute from the given annotation.
protected Object	findValue(Annotation[] annotationsToSearch) Determine a suggested value from any of the given candidate annotations.
protected Annotation	getFactoryMethodAnnotation(RootBeanDefinition bd, Class<? extends Annotation> type)
protected Annotation	getQualifiedElementAnnotation(RootBeanDefinition bd, Class<? extends Annotation> type)
Object	getSuggestedValue(DependencyDescriptor descriptor) Determine whether the given dependency declares a value annotation.
boolean	hasQualifier(DependencyDescriptor descriptor) Determine whether the given dependency declares a qualifier annotation.
boolean	isAutowireCandidate(BeanDefinitionHolder bdHolder, DependencyDescriptor descriptor) Determine whether the provided bean definition is an autowire candidate.
protected boolean	isQualifier(Class<? extends Annotation> annotationType) Checks whether the given annotation type is a recognized qualifier type.
boolean	isRequired(DependencyDescriptor descriptor) Determine whether the given dependency declares an autowired annotation, checking its required flag.
void	setValueAnnotationType(Class<? extends Annotation> valueAnnotationType) Set the 'value' annotation type, to be used on fields, method parameters and constructor parameters.

Methods inherited from class org.springframework.beans.factory.support.GenericTypeAwareAutowireCandidateResolver

checkGenericTypeMatch, getBeanFactory, getResolvedDecoratedDefinition, getReturnTypeForFactoryMethod, setBeanFactory

Methods inherited from class org.springframework.beans.factory.support.SimpleAutowireCandidateResolver

getLazyResolutionProxyIfNecessary

Methods inherited from class java.lang.Object

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

Constructor Detail

QualifierAnnotationAutowireCandidateResolver

public QualifierAnnotationAutowireCandidateResolver()

Create a new QualifierAnnotationAutowireCandidateResolver for Spring's standard Qualifier annotation.

Also supports JSR-330's Qualifier annotation, if available.

QualifierAnnotationAutowireCandidateResolver

public QualifierAnnotationAutowireCandidateResolver(Class<? extends Annotation> qualifierType)

Create a new QualifierAnnotationAutowireCandidateResolver for the given qualifier annotation type.

Parameters:

qualifierType - the qualifier annotation to look for

QualifierAnnotationAutowireCandidateResolver

public QualifierAnnotationAutowireCandidateResolver(Set<Class<? extends Annotation>> qualifierTypes)

Create a new QualifierAnnotationAutowireCandidateResolver for the given qualifier annotation types.

Parameters:

qualifierTypes - the qualifier annotations to look for

Method Detail

addQualifierType

public void addQualifierType(Class<? extends Annotation> qualifierType)

Register the given type to be used as a qualifier when autowiring.

This identifies qualifier annotations for direct use (on fields, method parameters and constructor parameters) as well as meta annotations that in turn identify actual qualifier annotations.

This implementation only supports annotations as qualifier types. The default is Spring's Qualifier annotation which serves as a qualifier for direct use and also as a meta annotation.

Parameters:

qualifierType - the annotation type to register

setValueAnnotationType

public void setValueAnnotationType(Class<? extends Annotation> valueAnnotationType)

Set the 'value' annotation type, to be used on fields, method parameters and constructor parameters.

The default value annotation type is the Spring-provided Value annotation.

This setter property exists so that developers can provide their own (non-Spring-specific) annotation type to indicate a default value expression for a specific argument.

isAutowireCandidate

public boolean isAutowireCandidate(BeanDefinitionHolder bdHolder,
                                   DependencyDescriptor descriptor)

Determine whether the provided bean definition is an autowire candidate.

To be considered a candidate the bean's autowire-candidate attribute must not have been set to 'false'. Also, if an annotation on the field or parameter to be autowired is recognized by this bean factory as a qualifier, the bean must 'match' against the annotation as well as any attributes it may contain. The bean definition must contain the same qualifier or match by meta attributes. A "value" attribute will fallback to match against the bean name or an alias if a qualifier or attribute does not match.

Specified by:

isAutowireCandidate in interface AutowireCandidateResolver

Overrides:

isAutowireCandidate in class GenericTypeAwareAutowireCandidateResolver

Parameters:

bdHolder - the bean definition including bean name and aliases

descriptor - the descriptor for the target method parameter or field

Returns:

whether the bean definition qualifies as autowire candidate

See Also:

Qualifier

checkQualifiers

protected boolean checkQualifiers(BeanDefinitionHolder bdHolder,
                                  Annotation[] annotationsToSearch)

Match the given qualifier annotations against the candidate bean definition.

isQualifier

protected boolean isQualifier(Class<? extends Annotation> annotationType)

Checks whether the given annotation type is a recognized qualifier type.

checkQualifier

protected boolean checkQualifier(BeanDefinitionHolder bdHolder,
                                 Annotation annotation,
                                 TypeConverter typeConverter)

Match the given qualifier annotation against the candidate bean definition.

getQualifiedElementAnnotation

@Nullable
protected Annotation getQualifiedElementAnnotation(RootBeanDefinition bd,
                                                             Class<? extends Annotation> type)

getFactoryMethodAnnotation

@Nullable
protected Annotation getFactoryMethodAnnotation(RootBeanDefinition bd,
                                                          Class<? extends Annotation> type)

isRequired

public boolean isRequired(DependencyDescriptor descriptor)

Determine whether the given dependency declares an autowired annotation, checking its required flag.

Specified by:

isRequired in interface AutowireCandidateResolver

Overrides:

isRequired in class SimpleAutowireCandidateResolver

Parameters:

descriptor - the descriptor for the target method parameter or field

Returns:

whether the descriptor is marked as required or possibly indicating non-required status some other way (e.g. through a parameter annotation)

See Also:

Autowired.required()

hasQualifier

public boolean hasQualifier(DependencyDescriptor descriptor)

Determine whether the given dependency declares a qualifier annotation.

Specified by:

hasQualifier in interface AutowireCandidateResolver

Overrides:

hasQualifier in class SimpleAutowireCandidateResolver

Parameters:

descriptor - the descriptor for the target method parameter or field

Returns:

whether the descriptor declares a qualifier, narrowing the candidate status beyond the type match

See Also:

isQualifier(Class), Qualifier

getSuggestedValue

@Nullable
public Object getSuggestedValue(DependencyDescriptor descriptor)

Determine whether the given dependency declares a value annotation.

Specified by:

getSuggestedValue in interface AutowireCandidateResolver

Overrides:

getSuggestedValue in class SimpleAutowireCandidateResolver

Parameters:

descriptor - the descriptor for the target method parameter or field

Returns:

the value suggested (typically an expression String), or null if none found

See Also:

Value

findValue

@Nullable
protected Object findValue(Annotation[] annotationsToSearch)

Determine a suggested value from any of the given candidate annotations.

extractValue

protected Object extractValue(AnnotationAttributes attr)

Extract the value attribute from the given annotation.

Since:

4.3