Package 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:
Cloneable, 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 (as well as its pre-Jakarta javax.inject.Qualifier equivalent), if available.

Since:
2.5
Author:
Mark Fisher, Juergen Hoeller, Stephane Nicoll, Sam Brannen
See Also:

  • Constructor Details

    • QualifierAnnotationAutowireCandidateResolver

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

      Also supports JSR-330's Qualifier annotation (as well as its pre-Jakarta javax.inject.Qualifier equivalent), 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 Details

    • 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 fall back 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:

    • 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)
      Check 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:

    • 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:

    • 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:

    • 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