org.springframework.beans.factory.annotation

Class AutowiredAnnotationBeanPostProcessor

java.lang.Object

org.springframework.beans.factory.config.InstantiationAwareBeanPostProcessorAdapter

org.springframework.beans.factory.annotation.AutowiredAnnotationBeanPostProcessor

All Implemented Interfaces:

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

public class AutowiredAnnotationBeanPostProcessor
extends InstantiationAwareBeanPostProcessorAdapter
implements MergedBeanDefinitionPostProcessor, PriorityOrdered, BeanFactoryAware

BeanPostProcessor implementation that autowires annotated fields, setter methods and arbitrary config methods. Such members to be injected are detected through a Java 5 annotation: 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.

Only one constructor (at max) of any given bean class may carry this annotation with the 'required' parameter set to true, indicating the constructor to autowire when used as a Spring bean. If multiple non-required constructors carry 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 default constructor (if present) will be used. An annotated constructor does not have to be public.

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.

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.

Note: 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.

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

See Also:

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

Nested Class Summary

Nested Classes

Modifier and Type	Class and Description
private class	AutowiredAnnotationBeanPostProcessor.AutowiredFieldElement Class representing injection information about an annotated field.
private class	AutowiredAnnotationBeanPostProcessor.AutowiredMethodElement Class representing injection information about an annotated method.

Field Summary

Fields

Modifier and Type	Field and Description
private java.util.Set<java.lang.Class<? extends java.lang.annotation.Annotation>>	autowiredAnnotationTypes
private ConfigurableListableBeanFactory	beanFactory
private java.util.Map<java.lang.Class<?>,java.lang.reflect.Constructor<?>[]>	candidateConstructorsCache
private java.util.Map<java.lang.String,InjectionMetadata>	injectionMetadataCache
protected Log	logger
private java.util.Set<java.lang.String>	lookupMethodsChecked
private int	order
private java.lang.String	requiredParameterName
private boolean	requiredParameterValue

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 annotation.

Method Summary

Modifier and Type	Method and Description
private InjectionMetadata	buildAutowiringMetadata(java.lang.Class<?> clazz)
java.lang.reflect.Constructor<?>[]	determineCandidateConstructors(java.lang.Class<?> beanClass, java.lang.String beanName) Determine the candidate constructors to use for the given bean.
protected boolean	determineRequiredStatus(AnnotationAttributes ann) Determine if the annotated field or method requires its dependency.
protected <T> java.util.Map<java.lang.String,T>	findAutowireCandidates(java.lang.Class<T> type) Obtain all beans of the given type as autowire candidates.
private AnnotationAttributes	findAutowiredAnnotation(java.lang.reflect.AccessibleObject ao)
private InjectionMetadata	findAutowiringMetadata(java.lang.String beanName, java.lang.Class<?> clazz, PropertyValues pvs)
int	getOrder() Return the order value of this object, with a higher value meaning greater in terms of sorting.
void	postProcessMergedBeanDefinition(RootBeanDefinition beanDefinition, java.lang.Class<?> beanType, java.lang.String beanName) Post-process the given merged bean definition for the specified bean.
PropertyValues	postProcessPropertyValues(PropertyValues pvs, java.beans.PropertyDescriptor[] pds, java.lang.Object bean, java.lang.String beanName) Post-process the given property values before the factory applies them to the given bean.
void	processInjection(java.lang.Object bean) 'Native' processing method for direct calls with an arbitrary target instance, resolving all of its fields and methods which are annotated with @Autowired.
private void	registerDependentBeans(java.lang.String beanName, java.util.Set<java.lang.String> autowiredBeanNames) Register the specified bean as dependent on the autowired beans.
private java.lang.Object	resolvedCachedArgument(java.lang.String beanName, java.lang.Object cachedArgument) Resolve the specified cached method argument or field value.
void	setAutowiredAnnotationType(java.lang.Class<? extends java.lang.annotation.Annotation> autowiredAnnotationType) Set the 'autowired' annotation type, to be used on constructors, fields, setter methods and arbitrary config methods.
void	setAutowiredAnnotationTypes(java.util.Set<java.lang.Class<? extends java.lang.annotation.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(java.lang.String requiredParameterName) Set the name of a parameter 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 org.springframework.beans.factory.config.InstantiationAwareBeanPostProcessorAdapter

getEarlyBeanReference, postProcessAfterInitialization, postProcessAfterInstantiation, postProcessBeforeInitialization, postProcessBeforeInstantiation, predictBeanType

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.BeanPostProcessor

postProcessAfterInitialization, postProcessBeforeInitialization

Field Detail

logger

protected final Log logger

autowiredAnnotationTypes

private final java.util.Set<java.lang.Class<? extends java.lang.annotation.Annotation>> autowiredAnnotationTypes

requiredParameterName

private java.lang.String requiredParameterName

requiredParameterValue

private boolean requiredParameterValue

order

private int order

beanFactory

private ConfigurableListableBeanFactory beanFactory

lookupMethodsChecked

private final java.util.Set<java.lang.String> lookupMethodsChecked

candidateConstructorsCache

private final java.util.Map<java.lang.Class<?>,java.lang.reflect.Constructor<?>[]> candidateConstructorsCache

injectionMetadataCache

private final java.util.Map<java.lang.String,InjectionMetadata> injectionMetadataCache

Constructor Detail

AutowiredAnnotationBeanPostProcessor

public AutowiredAnnotationBeanPostProcessor()

Create a new AutowiredAnnotationBeanPostProcessor for Spring's standard Autowired annotation.

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

Method Detail

setAutowiredAnnotationType

public void setAutowiredAnnotationType(java.lang.Class<? extends java.lang.annotation.Annotation> autowiredAnnotationType)

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

The default autowired annotation type is the Spring-provided Autowired annotation, as well as Value.

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(java.util.Set<java.lang.Class<? extends java.lang.annotation.Annotation>> autowiredAnnotationTypes)

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

The default autowired annotation type is the Spring-provided Autowired annotation, as well as Value.

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(java.lang.String requiredParameterName)

Set the name of a parameter 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

Return the order value of this object, with a higher value meaning greater in terms of sorting.

Normally starting with 0, with Integer.MAX_VALUE indicating the greatest value. Same order values will result in arbitrary positions for the affected objects.

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

Specified by:

getOrder in interface Ordered

Returns:

the order value

setBeanFactory

public void setBeanFactory(BeanFactory beanFactory)
                    throws BeansException

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.

Throws:

BeansException - in case of initialization errors

See Also:

BeanInitializationException

postProcessMergedBeanDefinition

public void postProcessMergedBeanDefinition(RootBeanDefinition beanDefinition,
                                            java.lang.Class<?> beanType,
                                            java.lang.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

determineCandidateConstructors

public java.lang.reflect.Constructor<?>[] determineCandidateConstructors(java.lang.Class<?> beanClass,
                                                                         java.lang.String beanName)
                                                                  throws BeansException

Description copied from interface: SmartInstantiationAwareBeanPostProcessor

Determine the candidate constructors to use for the given bean.

Specified by:

determineCandidateConstructors in interface SmartInstantiationAwareBeanPostProcessor

Overrides:

determineCandidateConstructors in class InstantiationAwareBeanPostProcessorAdapter

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:

BeansException - in case of errors

postProcessPropertyValues

public PropertyValues postProcessPropertyValues(PropertyValues pvs,
                                                java.beans.PropertyDescriptor[] pds,
                                                java.lang.Object bean,
                                                java.lang.String beanName)
                                         throws BeansException

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.

Specified by:

postProcessPropertyValues in interface InstantiationAwareBeanPostProcessor

Overrides:

postProcessPropertyValues in class InstantiationAwareBeanPostProcessorAdapter

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

Throws:

BeansException - in case of errors

See Also:

MutablePropertyValues

processInjection

public void processInjection(java.lang.Object bean)
                      throws BeansException

'Native' processing method for direct calls with an arbitrary target instance, resolving all of its fields and methods which are annotated with @Autowired.

Parameters:

bean - the target instance to process

Throws:

BeansException - if autowiring failed

findAutowiringMetadata

private InjectionMetadata findAutowiringMetadata(java.lang.String beanName,
                                                 java.lang.Class<?> clazz,
                                                 PropertyValues pvs)

buildAutowiringMetadata

private InjectionMetadata buildAutowiringMetadata(java.lang.Class<?> clazz)

findAutowiredAnnotation

private AnnotationAttributes findAutowiredAnnotation(java.lang.reflect.AccessibleObject ao)

determineRequiredStatus

protected boolean determineRequiredStatus(AnnotationAttributes 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

findAutowireCandidates

protected <T> java.util.Map<java.lang.String,T> findAutowireCandidates(java.lang.Class<T> type)
                                                                throws BeansException

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

registerDependentBeans

private void registerDependentBeans(java.lang.String beanName,
                                    java.util.Set<java.lang.String> autowiredBeanNames)

Register the specified bean as dependent on the autowired beans.

resolvedCachedArgument

private java.lang.Object resolvedCachedArgument(java.lang.String beanName,
                                                java.lang.Object cachedArgument)

Resolve the specified cached method argument or field value.