infra.beans.factory.support.AutowireCandidateResolver Maven / Gradle / Ivy
/*
* Copyright 2017 - 2024 the original author or authors.
*
* This program is free software: you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation, either version 3 of the License, or
* (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program. If not, see [https://www.gnu.org/licenses/]
*/
package infra.beans.factory.support;
import infra.beans.BeanUtils;
import infra.beans.factory.annotation.QualifierAnnotationAutowireCandidateResolver;
import infra.beans.factory.config.BeanDefinition;
import infra.beans.factory.config.BeanDefinitionHolder;
import infra.beans.factory.config.ConfigurableBeanFactory;
import infra.beans.factory.config.DependencyDescriptor;
import infra.lang.Nullable;
/**
* Strategy interface for determining whether a specific bean definition
* qualifies as an autowire candidate for a specific dependency.
*
* @author Juergen Hoeller
* @author Mark Fisher
* @author Harry Yang
* @since 4.0 2021/12/22 21:00
*/
public interface AutowireCandidateResolver {
/**
* Determine whether the given bean definition qualifies as an
* autowire candidate for the given dependency.
* The default implementation checks
* {@link BeanDefinition#isAutowireCandidate()}.
*
* @param definition the bean definition including bean name and aliases
* @param descriptor the descriptor for the target method parameter or field
* @return whether the bean definition qualifies as autowire candidate
* @see BeanDefinition#isAutowireCandidate()
*/
default boolean isAutowireCandidate(BeanDefinitionHolder definition, DependencyDescriptor descriptor) {
return definition.getBeanDefinition().isAutowireCandidate();
}
/**
* Determine whether the given descriptor is effectively required.
*
The default implementation checks {@link DependencyDescriptor#isRequired()}.
*
* @param descriptor the descriptor for the target method parameter or field
* @return whether the descriptor is marked as required or possibly indicating
* non-required status some other way (e.g. through a parameter annotation)
* @see DependencyDescriptor#isRequired()
*/
default boolean isRequired(DependencyDescriptor descriptor) {
return descriptor.isRequired();
}
/**
* Determine whether a target bean name is suggested for the given dependency
* (typically - but not necessarily - declared with a single-value qualifier).
*
* @param descriptor the descriptor for the target method parameter or field
* @return the qualifier value, if any
*/
@Nullable
default String getSuggestedName(DependencyDescriptor descriptor) {
return null;
}
/**
* Determine whether a default value is suggested for the given dependency.
*
The default implementation simply returns {@code null}.
*
* @param descriptor the descriptor for the target method parameter or field
* @return the value suggested (typically an expression String),
* or {@code null} if none found
* @since 4.0
*/
@Nullable
default Object getSuggestedValue(DependencyDescriptor descriptor) {
return null;
}
/**
* Determine whether the given descriptor declares a qualifier beyond the type
* (typically - but not necessarily - a specific kind of annotation).
*
The default implementation returns {@code false}.
*
* @param descriptor the descriptor for the target method parameter or field
* @return whether the descriptor declares a qualifier, narrowing the candidate
* status beyond the type match
* @see QualifierAnnotationAutowireCandidateResolver#hasQualifier
*/
default boolean hasQualifier(DependencyDescriptor descriptor) {
return false;
}
/**
* Build a proxy for lazy resolution of the actual dependency target,
* if demanded by the injection point.
*
The default implementation simply returns {@code null}.
*
* @param descriptor the descriptor for the target method parameter or field
* @param beanName the name of the bean that contains the injection point
* @return the lazy resolution proxy for the actual dependency target,
* or {@code null} if straight resolution is to be performed
*/
@Nullable
default Object getLazyResolutionProxyIfNecessary(DependencyDescriptor descriptor, @Nullable String beanName) {
return null;
}
/**
* Determine the proxy class for lazy resolution of the dependency target,
* if demanded by the injection point.
*
The default implementation simply returns {@code null}.
*
* @param descriptor the descriptor for the target method parameter or field
* @param beanName the name of the bean that contains the injection point
* @return the lazy resolution proxy class for the dependency target, if any
*/
@Nullable
default Class getLazyResolutionProxyClass(DependencyDescriptor descriptor, @Nullable String beanName) {
return null;
}
/**
* Return a clone of this resolver instance if necessary, retaining its local
* configuration and allowing for the cloned instance to get associated with
* a new bean factory, or this original instance if there is no such state.
*
The default implementation creates a separate instance via the default
* class constructor, assuming no specific configuration state to copy.
* Subclasses may override this with custom configuration state handling
* or with standard {@link Cloneable} support (as implemented by Framework's
* own configurable {@code AutowireCandidateResolver} variants), or simply
* return {@code this} (as in {@link SimpleAutowireCandidateResolver}).
*
* @see GenericTypeAwareAutowireCandidateResolver#cloneIfNecessary()
* @see ConfigurableBeanFactory#copyConfigurationFrom
*/
default AutowireCandidateResolver cloneIfNecessary() {
return BeanUtils.newInstance(getClass());
}
}