org.springframework.beans.factory.config

Class DependencyDescriptor

java.lang.Object

org.springframework.beans.factory.InjectionPoint

org.springframework.beans.factory.config.DependencyDescriptor

All Implemented Interfaces:

java.io.Serializable

Direct Known Subclasses:

AbstractAutowireCapableBeanFactory.AutowireByTypeDependencyDescriptor, CommonAnnotationBeanPostProcessor.LookupDependencyDescriptor

public class DependencyDescriptor
extends InjectionPoint
implements java.io.Serializable

Descriptor for a specific dependency that is about to be injected. Wraps a constructor parameter, a method parameter or a field, allowing unified access to their metadata.

Since:

2.5

Author:

Juergen Hoeller

See Also:

Serialized Form

Field Summary

Fields

Modifier and Type	Field and Description
private java.lang.Class<?>	containingClass
private java.lang.Class<?>	declaringClass
private boolean	eager
private java.lang.String	fieldName
private java.lang.String	methodName
private int	nestingLevel
private int	parameterIndex
private java.lang.Class<?>[]	parameterTypes
private boolean	required

Fields inherited from class org.springframework.beans.factory.InjectionPoint

field, methodParameter

Constructor Summary

Constructors

Constructor and Description
DependencyDescriptor(DependencyDescriptor original) Copy constructor.
DependencyDescriptor(java.lang.reflect.Field field, boolean required) Create a new descriptor for a field.
DependencyDescriptor(java.lang.reflect.Field field, boolean required, boolean eager) Create a new descriptor for a field.
DependencyDescriptor(MethodParameter methodParameter, boolean required) Create a new descriptor for a method or constructor parameter.
DependencyDescriptor(MethodParameter methodParameter, boolean required, boolean eager) Create a new descriptor for a method or constructor parameter.

Method Summary

Modifier and Type	Method and Description
boolean	equals(java.lang.Object other)
boolean	fallbackMatchAllowed() Return whether a fallback match is allowed.
DependencyDescriptor	forFallbackMatch() Return a variant of this descriptor that is intended for a fallback match.
java.lang.Class<?>	getCollectionType() Determine the generic element type of the wrapped Collection parameter/field, if any.
java.lang.String	getDependencyName() Determine the name of the wrapped parameter/field.
java.lang.Class<?>	getDependencyType() Determine the declared (non-generic) type of the wrapped parameter/field.
java.lang.Class<?>	getMapKeyType() Determine the generic key type of the wrapped Map parameter/field, if any.
java.lang.Class<?>	getMapValueType() Determine the generic value type of the wrapped Map parameter/field, if any.
ResolvableType	getResolvableType() Build a ResolvableType object for the wrapped parameter/field.
void	increaseNestingLevel() Increase this descriptor's nesting level.
void	initParameterNameDiscovery(ParameterNameDiscoverer parameterNameDiscoverer) Initialize parameter name discovery for the underlying method parameter, if any.
boolean	isEager() Return whether this dependency is 'eager' in the sense of eagerly resolving potential target beans for type matching.
boolean	isRequired() Return whether this dependency is required.
private void	readObject(java.io.ObjectInputStream ois)
java.lang.Object	resolveCandidate(java.lang.String beanName, BeanFactory beanFactory) Resolve the specified bean name, as a candidate result of the matching algorithm for this dependency, to a bean instance from the given factory.
java.lang.Object	resolveNotUnique(java.lang.Class<?> type, java.util.Map<java.lang.String,java.lang.Object> matchingBeans) Resolve the specified not-unique scenario: by default, throwing a NoUniqueBeanDefinitionException.
void	setContainingClass(java.lang.Class<?> containingClass) Optionally set the concrete class that contains this dependency.

Methods inherited from class org.springframework.beans.factory.InjectionPoint

getAnnotatedElement, getAnnotations, getDeclaredType, getField, getMember, getMethodParameter, hashCode, toString

Methods inherited from class java.lang.Object

clone, finalize, getClass, notify, notifyAll, wait, wait, wait

Field Detail

declaringClass

private final java.lang.Class<?> declaringClass

methodName

private java.lang.String methodName

parameterTypes

private java.lang.Class<?>[] parameterTypes

parameterIndex

private int parameterIndex

fieldName

private java.lang.String fieldName

required

private final boolean required

eager

private final boolean eager

nestingLevel

private int nestingLevel

containingClass

private java.lang.Class<?> containingClass

Constructor Detail

DependencyDescriptor

public DependencyDescriptor(MethodParameter methodParameter,
                            boolean required)

Create a new descriptor for a method or constructor parameter. Considers the dependency as 'eager'.

Parameters:

methodParameter - the MethodParameter to wrap

required - whether the dependency is required

DependencyDescriptor

public DependencyDescriptor(MethodParameter methodParameter,
                            boolean required,
                            boolean eager)

Create a new descriptor for a method or constructor parameter.

Parameters:

methodParameter - the MethodParameter to wrap

required - whether the dependency is required

eager - whether this dependency is 'eager' in the sense of eagerly resolving potential target beans for type matching

DependencyDescriptor

public DependencyDescriptor(java.lang.reflect.Field field,
                            boolean required)

Create a new descriptor for a field. Considers the dependency as 'eager'.

Parameters:

field - the field to wrap

required - whether the dependency is required

DependencyDescriptor

public DependencyDescriptor(java.lang.reflect.Field field,
                            boolean required,
                            boolean eager)

Create a new descriptor for a field.

Parameters:

field - the field to wrap

required - whether the dependency is required

eager - whether this dependency is 'eager' in the sense of eagerly resolving potential target beans for type matching

DependencyDescriptor

public DependencyDescriptor(DependencyDescriptor original)

Copy constructor.

Parameters:

original - the original descriptor to create a copy from

Method Detail

isRequired

public boolean isRequired()

Return whether this dependency is required.

isEager

public boolean isEager()

Return whether this dependency is 'eager' in the sense of eagerly resolving potential target beans for type matching.

resolveNotUnique

public java.lang.Object resolveNotUnique(java.lang.Class<?> type,
                                         java.util.Map<java.lang.String,java.lang.Object> matchingBeans)
                                  throws BeansException

Resolve the specified not-unique scenario: by default, throwing a NoUniqueBeanDefinitionException.

Subclasses may override this to select one of the instances or to opt out with no result at all through returning null.

Parameters:

type - the requested bean type

matchingBeans - a map of bean names and corresponding bean instances which have been pre-selected for the given type (qualifiers etc already applied)

Returns:

a bean instance to proceed with, or null for none

Throws:

BeansException - in case of the not-unique scenario being fatal

Since:

4.3

resolveCandidate

public java.lang.Object resolveCandidate(java.lang.String beanName,
                                         BeanFactory beanFactory)

Resolve the specified bean name, as a candidate result of the matching algorithm for this dependency, to a bean instance from the given factory.

The default implementation calls BeanFactory.getBean(String). Subclasses may provide additional arguments or other customizations.

Parameters:

beanName - the bean name, as a candidate result for this dependency

beanFactory - the associated factory

Returns:

the bean instance (never null)

Since:

4.3

See Also:

BeanFactory.getBean(String)

increaseNestingLevel

public void increaseNestingLevel()

Increase this descriptor's nesting level.

See Also:

MethodParameter.increaseNestingLevel()

setContainingClass

public void setContainingClass(java.lang.Class<?> containingClass)

Optionally set the concrete class that contains this dependency. This may differ from the class that declares the parameter/field in that it may be a subclass thereof, potentially substituting type variables.

Since:

4.0

getResolvableType

public ResolvableType getResolvableType()

Build a ResolvableType object for the wrapped parameter/field.

Since:

4.0

fallbackMatchAllowed

public boolean fallbackMatchAllowed()

Return whether a fallback match is allowed.

This is false by default but may be overridden to return true in order to suggest to a AutowireCandidateResolver that a fallback match is acceptable as well.

Since:

4.0

forFallbackMatch

public DependencyDescriptor forFallbackMatch()

Return a variant of this descriptor that is intended for a fallback match.

Since:

4.0

See Also:

fallbackMatchAllowed()

initParameterNameDiscovery

public void initParameterNameDiscovery(ParameterNameDiscoverer parameterNameDiscoverer)

Initialize parameter name discovery for the underlying method parameter, if any.

This method does not actually try to retrieve the parameter name at this point; it just allows discovery to happen when the application calls getDependencyName() (if ever).

getDependencyName

public java.lang.String getDependencyName()

Determine the name of the wrapped parameter/field.

Returns:

the declared name (never null)

getDependencyType

public java.lang.Class<?> getDependencyType()

Determine the declared (non-generic) type of the wrapped parameter/field.

Returns:

the declared type (never null)

getCollectionType

public java.lang.Class<?> getCollectionType()

Determine the generic element type of the wrapped Collection parameter/field, if any.

Returns:

the generic type, or null if none

getMapKeyType

public java.lang.Class<?> getMapKeyType()

Determine the generic key type of the wrapped Map parameter/field, if any.

Returns:

the generic type, or null if none

getMapValueType

public java.lang.Class<?> getMapValueType()

Determine the generic value type of the wrapped Map parameter/field, if any.

Returns:

the generic type, or null if none

equals

public boolean equals(java.lang.Object other)

Overrides:

equals in class InjectionPoint

readObject

private void readObject(java.io.ObjectInputStream ois)
                 throws java.io.IOException,
                        java.lang.ClassNotFoundException

Throws:

java.io.IOException

java.lang.ClassNotFoundException