org.springframework.beans.factory.annotation

Class AutowiredAnnotationBeanPostProcessor

java.lang.Object

org.springframework.beans.factory.annotation.AutowiredAnnotationBeanPostProcessor

All Implemented Interfaces:

Aware, BeanFactoryAware, BeanPostProcessor, InstantiationAwareBeanPostProcessor, SmartInstantiationAwareBeanPostProcessor, MergedBeanDefinitionPostProcessor, Ordered, PriorityOrdered

public class AutowiredAnnotationBeanPostProcessor
extends Object
implements SmartInstantiationAwareBeanPostProcessor, MergedBeanDefinitionPostProcessor, PriorityOrdered, BeanFactoryAware

BeanPostProcessor implementation that autowires annotated fields, setter methods, and arbitrary config methods. Such members to be injected are detected through annotations: by default, Spring's @Autowired and @Value annotations.

Also supports JSR-330's @Inject annotation, if available, as a direct alternative to Spring's own @Autowired.

Autowired Constructors

Only one constructor of any given bean class may declare this annotation with the 'required' attribute set to true, indicating the constructor to autowire when used as a Spring bean. Furthermore, if the 'required' attribute is set to true, only a single constructor may be annotated with @Autowired. If multiple non-required constructors declare the annotation, they will be considered as candidates for autowiring. The constructor with the greatest number of dependencies that can be satisfied by matching beans in the Spring container will be chosen. If none of the candidates can be satisfied, then a primary/default constructor (if present) will be used. If a class only declares a single constructor to begin with, it will always be used, even if not annotated. An annotated constructor does not have to be public.

Autowired Fields

Fields are injected right after construction of a bean, before any config methods are invoked. Such a config field does not have to be public.

Autowired Methods

Config methods may have an arbitrary name and any number of arguments; each of those arguments will be autowired with a matching bean in the Spring container. Bean property setter methods are effectively just a special case of such a general config method. Config methods do not have to be public.

Annotation Config vs. XML Config

A default AutowiredAnnotationBeanPostProcessor will be registered by the "context:annotation-config" and "context:component-scan" XML tags. Remove or turn off the default annotation configuration there if you intend to specify a custom AutowiredAnnotationBeanPostProcessor bean definition.

NOTE: Annotation injection will be performed before XML injection; thus the latter configuration will override the former for properties wired through both approaches.

@Lookup Methods

In addition to regular injection points as discussed above, this post-processor also handles Spring's @Lookup annotation which identifies lookup methods to be replaced by the container at runtime. This is essentially a type-safe version of getBean(Class, args) and getBean(String, args). See @Lookup's javadoc for details.

Since:

2.5

Author:

Juergen Hoeller, Mark Fisher, Stephane Nicoll, Sebastien Deleuze, Sam Brannen

See Also:

setAutowiredAnnotationType(java.lang.Class<? extends java.lang.annotation.Annotation>), Autowired, Value

Field Summary

Fields

Modifier and Type	Field and Description
protected Log	logger

Fields inherited from interface org.springframework.core.Ordered

HIGHEST_PRECEDENCE, LOWEST_PRECEDENCE

Constructor Summary

Constructors

Constructor and Description
AutowiredAnnotationBeanPostProcessor() Create a new AutowiredAnnotationBeanPostProcessor for Spring's standard @Autowired and @Value annotations.

Method Summary

Modifier and Type	Method and Description
Constructor<?>[]	determineCandidateConstructors(Class<?> beanClass, String beanName) Determine the candidate constructors to use for the given bean.
protected boolean	determineRequiredStatus(AnnotationAttributes ann) Deprecated. since 5.2, in favor of determineRequiredStatus(MergedAnnotation)
protected boolean	determineRequiredStatus(MergedAnnotation<?> ann) Determine if the annotated field or method requires its dependency.
protected <T> Map<String,T>	findAutowireCandidates(Class<T> type) Deprecated. since 5.3.24 since it is unused in the meantime
int	getOrder() Get the order value of this object.
void	postProcessMergedBeanDefinition(RootBeanDefinition beanDefinition, Class<?> beanType, String beanName) Post-process the given merged bean definition for the specified bean.
PropertyValues	postProcessProperties(PropertyValues pvs, Object bean, String beanName) Post-process the given property values before the factory applies them to the given bean, without any need for property descriptors.
PropertyValues	postProcessPropertyValues(PropertyValues pvs, PropertyDescriptor[] pds, Object bean, String beanName) Deprecated.
void	processInjection(Object bean) 'Native' processing method for direct calls with an arbitrary target instance, resolving all of its fields and methods which are annotated with one of the configured 'autowired' annotation types.
void	resetBeanDefinition(String beanName) A notification that the bean definition for the specified name has been reset, and that this post-processor should clear any metadata for the affected bean.
void	setAutowiredAnnotationType(Class<? extends Annotation> autowiredAnnotationType) Set the 'autowired' annotation type, to be used on constructors, fields, setter methods, and arbitrary config methods.
void	setAutowiredAnnotationTypes(Set<Class<? extends Annotation>> autowiredAnnotationTypes) Set the 'autowired' annotation types, to be used on constructors, fields, setter methods, and arbitrary config methods.
void	setBeanFactory(BeanFactory beanFactory) Callback that supplies the owning factory to a bean instance.
void	setOrder(int order)
void	setRequiredParameterName(String requiredParameterName) Set the name of an attribute of the annotation that specifies whether it is required.
void	setRequiredParameterValue(boolean requiredParameterValue) Set the boolean value that marks a dependency as required.

Methods inherited from class java.lang.Object

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

Methods inherited from interface org.springframework.beans.factory.config.SmartInstantiationAwareBeanPostProcessor

getEarlyBeanReference, predictBeanType

Methods inherited from interface org.springframework.beans.factory.config.InstantiationAwareBeanPostProcessor

postProcessAfterInstantiation, postProcessBeforeInstantiation

Methods inherited from interface org.springframework.beans.factory.config.BeanPostProcessor

postProcessAfterInitialization, postProcessBeforeInitialization

Field Detail

logger

protected final Log logger

Constructor Detail

AutowiredAnnotationBeanPostProcessor

public AutowiredAnnotationBeanPostProcessor()

Create a new AutowiredAnnotationBeanPostProcessor for Spring's standard @Autowired and @Value annotations.

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

Method Detail

setAutowiredAnnotationType

public void setAutowiredAnnotationType(Class<? extends Annotation> autowiredAnnotationType)

Set the 'autowired' annotation type, to be used on constructors, fields, setter methods, and arbitrary config methods.

The default autowired annotation types are the Spring-provided @Autowired and @Value annotations as well as JSR-330's @Inject annotation, if available.

This setter property exists so that developers can provide their own (non-Spring-specific) annotation type to indicate that a member is supposed to be autowired.

setAutowiredAnnotationTypes

public void setAutowiredAnnotationTypes(Set<Class<? extends Annotation>> autowiredAnnotationTypes)

Set the 'autowired' annotation types, to be used on constructors, fields, setter methods, and arbitrary config methods.

The default autowired annotation types are the Spring-provided @Autowired and @Value annotations as well as JSR-330's @Inject annotation, if available.

This setter property exists so that developers can provide their own (non-Spring-specific) annotation types to indicate that a member is supposed to be autowired.

setRequiredParameterName

public void setRequiredParameterName(String requiredParameterName)

Set the name of an attribute of the annotation that specifies whether it is required.

See Also:

setRequiredParameterValue(boolean)

setRequiredParameterValue

public void setRequiredParameterValue(boolean requiredParameterValue)

Set the boolean value that marks a dependency as required.

For example if using 'required=true' (the default), this value should be true; but if using 'optional=false', this value should be false.

See Also:

setRequiredParameterName(String)

setOrder

public void setOrder(int order)

getOrder

public int getOrder()

Description copied from interface: Ordered

Get the order value of this object.

Higher values are interpreted as lower priority. As a consequence, the object with the lowest value has the highest priority (somewhat analogous to Servlet load-on-startup values).

Same order values will result in arbitrary sort positions for the affected objects.

Specified by:

getOrder in interface Ordered

Returns:

the order value

See Also:

Ordered.HIGHEST_PRECEDENCE, Ordered.LOWEST_PRECEDENCE

setBeanFactory

public void setBeanFactory(BeanFactory beanFactory)

Description copied from interface: BeanFactoryAware

Callback that supplies the owning factory to a bean instance.

Invoked after the population of normal bean properties but before an initialization callback such as InitializingBean.afterPropertiesSet() or a custom init-method.

Specified by:

setBeanFactory in interface BeanFactoryAware

Parameters:

beanFactory - owning BeanFactory (never null). The bean can immediately call methods on the factory.

See Also:

BeanInitializationException

postProcessMergedBeanDefinition

public void postProcessMergedBeanDefinition(RootBeanDefinition beanDefinition,
                                            Class<?> beanType,
                                            String beanName)

Description copied from interface: MergedBeanDefinitionPostProcessor

Post-process the given merged bean definition for the specified bean.

Specified by:

postProcessMergedBeanDefinition in interface MergedBeanDefinitionPostProcessor

Parameters:

beanDefinition - the merged bean definition for the bean

beanType - the actual type of the managed bean instance

beanName - the name of the bean

See Also:

AbstractAutowireCapableBeanFactory.applyMergedBeanDefinitionPostProcessors(org.springframework.beans.factory.support.RootBeanDefinition, java.lang.Class<?>, java.lang.String)

resetBeanDefinition

public void resetBeanDefinition(String beanName)

Description copied from interface: MergedBeanDefinitionPostProcessor

A notification that the bean definition for the specified name has been reset, and that this post-processor should clear any metadata for the affected bean.

The default implementation is empty.

Specified by:

resetBeanDefinition in interface MergedBeanDefinitionPostProcessor

Parameters:

beanName - the name of the bean

See Also:

DefaultListableBeanFactory.resetBeanDefinition(java.lang.String)

determineCandidateConstructors

@Nullable
public Constructor<?>[] determineCandidateConstructors(Class<?> beanClass,
                                                                 String beanName)
                                                          throws BeanCreationException

Description copied from interface: SmartInstantiationAwareBeanPostProcessor

Determine the candidate constructors to use for the given bean.

The default implementation returns null.

Specified by:

determineCandidateConstructors in interface SmartInstantiationAwareBeanPostProcessor

Parameters:

beanClass - the raw class of the bean (never null)

beanName - the name of the bean

Returns:

the candidate constructors, or null if none specified

Throws:

BeanCreationException

postProcessProperties

public PropertyValues postProcessProperties(PropertyValues pvs,
                                            Object bean,
                                            String beanName)

Description copied from interface: InstantiationAwareBeanPostProcessor

Post-process the given property values before the factory applies them to the given bean, without any need for property descriptors.

Implementations should return null (the default) if they provide a custom InstantiationAwareBeanPostProcessor.postProcessPropertyValues(org.springframework.beans.PropertyValues, java.beans.PropertyDescriptor[], java.lang.Object, java.lang.String) implementation, and pvs otherwise. In a future version of this interface (with InstantiationAwareBeanPostProcessor.postProcessPropertyValues(org.springframework.beans.PropertyValues, java.beans.PropertyDescriptor[], java.lang.Object, java.lang.String) removed), the default implementation will return the given pvs as-is directly.

Specified by:

postProcessProperties in interface InstantiationAwareBeanPostProcessor

Parameters:

pvs - the property values that the factory is about to apply (never null)

bean - the bean instance created, but whose properties have not yet been set

beanName - the name of the bean

Returns:

the actual property values to apply to the given bean (can be the passed-in PropertyValues instance), or null which proceeds with the existing properties but specifically continues with a call to InstantiationAwareBeanPostProcessor.postProcessPropertyValues(org.springframework.beans.PropertyValues, java.beans.PropertyDescriptor[], java.lang.Object, java.lang.String) (requiring initialized PropertyDescriptors for the current bean class)

See Also:

InstantiationAwareBeanPostProcessor.postProcessPropertyValues(org.springframework.beans.PropertyValues, java.beans.PropertyDescriptor[], java.lang.Object, java.lang.String)

postProcessPropertyValues

@Deprecated
public PropertyValues postProcessPropertyValues(PropertyValues pvs,
                                                            PropertyDescriptor[] pds,
                                                            Object bean,
                                                            String beanName)

Deprecated.

Description copied from interface: InstantiationAwareBeanPostProcessor

Post-process the given property values before the factory applies them to the given bean. Allows for checking whether all dependencies have been satisfied, for example based on a "Required" annotation on bean property setters.

Also allows for replacing the property values to apply, typically through creating a new MutablePropertyValues instance based on the original PropertyValues, adding or removing specific values.

The default implementation returns the given pvs as-is.

Specified by:

postProcessPropertyValues in interface InstantiationAwareBeanPostProcessor

Parameters:

pvs - the property values that the factory is about to apply (never null)

pds - the relevant property descriptors for the target bean (with ignored dependency types - which the factory handles specifically - already filtered out)

bean - the bean instance created, but whose properties have not yet been set

beanName - the name of the bean

Returns:

the actual property values to apply to the given bean (can be the passed-in PropertyValues instance), or null to skip property population

See Also:

InstantiationAwareBeanPostProcessor.postProcessProperties(org.springframework.beans.PropertyValues, java.lang.Object, java.lang.String), MutablePropertyValues

processInjection

public void processInjection(Object bean)
                      throws BeanCreationException

'Native' processing method for direct calls with an arbitrary target instance, resolving all of its fields and methods which are annotated with one of the configured 'autowired' annotation types.

Parameters:

bean - the target instance to process

Throws:

BeanCreationException - if autowiring failed

See Also:

setAutowiredAnnotationTypes(Set)

determineRequiredStatus

protected boolean determineRequiredStatus(MergedAnnotation<?> ann)

Determine if the annotated field or method requires its dependency.

A 'required' dependency means that autowiring should fail when no beans are found. Otherwise, the autowiring process will simply bypass the field or method when no beans are found.

Parameters:

ann - the Autowired annotation

Returns:

whether the annotation indicates that a dependency is required

determineRequiredStatus

@Deprecated
protected boolean determineRequiredStatus(AnnotationAttributes ann)

Deprecated. since 5.2, in favor of determineRequiredStatus(MergedAnnotation)

Determine if the annotated field or method requires its dependency.

A 'required' dependency means that autowiring should fail when no beans are found. Otherwise, the autowiring process will simply bypass the field or method when no beans are found.

Parameters:

ann - the Autowired annotation

Returns:

whether the annotation indicates that a dependency is required

findAutowireCandidates

@Deprecated
protected <T> Map<String,T> findAutowireCandidates(Class<T> type)
                                                        throws BeansException

Deprecated. since 5.3.24 since it is unused in the meantime

Obtain all beans of the given type as autowire candidates.

Parameters:

type - the type of the bean

Returns:

the target beans, or an empty Collection if no bean of this type is found

Throws:

BeansException - if bean retrieval failed