DependencyDescriptor (Spring Framework 5.1.8.RELEASE API)

java.lang.Object
- org.springframework.beans.factory.InjectionPoint
- - org.springframework.beans.factory.config.DependencyDescriptor

All Implemented Interfaces:

Serializable
```
public class DependencyDescriptor
extends InjectionPoint
implements 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 inherited from class org.springframework.beans.factory.InjectionPoint
  field, methodParameter

Constructor Summary

Constructors
Constructor and Description
`DependencyDescriptor(DependencyDescriptor original)` Copy constructor.
`DependencyDescriptor(Field field, boolean required)` Create a new descriptor for a field.
`DependencyDescriptor(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

All Methods Instance Methods Concrete Methods Deprecated Methods
Modifier and Type	Method and Description
`boolean`	`equals(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.
`String`	`getDependencyName()` Determine the name of the wrapped parameter/field.
`Class<?>`	`getDependencyType()` Determine the declared (non-generic) type of the wrapped parameter/field.
`ResolvableType`	`getResolvableType()` Build a `ResolvableType` object for the wrapped parameter/field.
`TypeDescriptor`	`getTypeDescriptor()` Build a `TypeDescriptor` object for the wrapped parameter/field.
`int`	`hashCode()`
`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.
`Object`	`resolveCandidate(String beanName, Class<?> requiredType, 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.
`Object`	`resolveNotUnique(Class<?> type, Map<String,Object> matchingBeans)` Deprecated. as of 5.1, in favor of `resolveNotUnique(ResolvableType, Map)`
`Object`	`resolveNotUnique(ResolvableType type, Map<String,Object> matchingBeans)` Resolve the specified not-unique scenario: by default, throwing a `NoUniqueBeanDefinitionException`.
`Object`	`resolveShortcut(BeanFactory beanFactory)` Resolve a shortcut for this dependency against the given factory, for example taking some pre-resolved information into account.
`void`	`setContainingClass(Class<?> containingClass)` Optionally set the concrete class that contains this dependency.

Methods inherited from class org.springframework.beans.factory.InjectionPoint
getAnnotatedElement, getAnnotation, getAnnotations, getDeclaredType, getField, getMember, getMethodParameter, obtainMethodParameter, toString

Methods inherited from class java.lang.Object
clone, finalize, getClass, notify, notifyAll, wait, wait, wait

- 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(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(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.
    Optional semantics are derived from Java 8's Optional, any variant of a parameter-level Nullable annotation (such as from JSR-305 or the FindBugs set of annotations), or a language-level nullable type declaration in Kotlin.
  - isEager
```
public boolean isEager()
```
    Return whether this dependency is 'eager' in the sense of eagerly resolving potential target beans for type matching.
  - resolveNotUnique
```
@Nullable
public Object resolveNotUnique(ResolvableType type,
                                         Map<String,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:
    
    5.1
  - resolveNotUnique
```
@Deprecated
 @Nullable
public Object resolveNotUnique(Class<?> type,
                                                      Map<String,Object> matchingBeans)
                                               throws BeansException
```
    Deprecated. as of 5.1, in favor of resolveNotUnique(ResolvableType, Map)
    
    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
  - resolveShortcut
```
@Nullable
public Object resolveShortcut(BeanFactory beanFactory)
                                 throws BeansException
```
    Resolve a shortcut for this dependency against the given factory, for example taking some pre-resolved information into account.
    The resolution algorithm will first attempt to resolve a shortcut through this method before going into the regular type matching algorithm across all beans. Subclasses may override this method to improve resolution performance based on pre-cached information while still receiving InjectionPoint exposure etc.
    
    Parameters:
    
    beanFactory - the associated factory
    
    Returns:
    
    the shortcut result if any, or null if none
    
    Throws:
    
    BeansException - if the shortcut could not be obtained
    
    Since:
    
    4.3.1
  - resolveCandidate
```
public Object resolveCandidate(String beanName,
                               Class<?> requiredType,
                               BeanFactory beanFactory)
                        throws BeansException
```
    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
    
    requiredType - the expected type of the bean (as an assertion)
    
    beanFactory - the associated factory
    
    Returns:
    
    the bean instance (never null)
    
    Throws:
    
    BeansException - if the bean could not be obtained
    
    Since:
    
    4.3.2
    
    See Also:
    
    BeanFactory.getBean(String)
  - increaseNestingLevel
```
public void increaseNestingLevel()
```
    Increase this descriptor's nesting level.
    
    See Also:
    
    MethodParameter.increaseNestingLevel()
  - setContainingClass
```
public void setContainingClass(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
  - getTypeDescriptor
```
public TypeDescriptor getTypeDescriptor()
```
    Build a TypeDescriptor object for the wrapped parameter/field.
    
    Since:
    
    5.1.4
  - 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 an 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(@Nullable
                                       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
```
@Nullable
public String getDependencyName()
```
    Determine the name of the wrapped parameter/field.
    
    Returns:
    
    the declared name (never null)
  - getDependencyType
```
public Class<?> getDependencyType()
```
    Determine the declared (non-generic) type of the wrapped parameter/field.
    
    Returns:
    
    the declared type (never null)
  - equals
```
public boolean equals(Object other)
```
    Overrides:
    
    equals in class InjectionPoint
  - hashCode
```
public int hashCode()
```
    Overrides:
    
    hashCode in class InjectionPoint

Class DependencyDescriptor

Field Summary

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

Constructor Summary

Method Summary

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

Methods inherited from class java.lang.Object

Constructor Detail

DependencyDescriptor

DependencyDescriptor

DependencyDescriptor

DependencyDescriptor

DependencyDescriptor

Method Detail

isRequired

isEager

resolveNotUnique

resolveNotUnique

resolveShortcut

resolveCandidate

increaseNestingLevel

setContainingClass

getResolvableType

getTypeDescriptor

fallbackMatchAllowed

forFallbackMatch

initParameterNameDiscovery

getDependencyName

getDependencyType

equals

hashCode