java.lang.Object
- org.springframework.core.MethodParameter

Direct Known Subclasses:
SynthesizingMethodParameter
```
public class MethodParameter
extends Object
```
Helper class that encapsulates the specification of a method parameter, i.e. a Method or Constructor plus a parameter index and a nested type index for a declared generic type. Useful as a specification object to pass along.
As of 4.2, there is a SynthesizingMethodParameter subclass available which synthesizes annotations with attribute aliases. That subclass is used for web and message endpoint processing, in particular.
Since:
2.0
Author:
Juergen Hoeller, Rob Harrop, Andy Clement, Sam Brannen
See Also:
SynthesizingMethodParameter

Constructor Summary

Constructors
Constructor	Description
`MethodParameter(Constructor<?> constructor, int parameterIndex)`	Create a new MethodParameter for the given constructor, with nesting level 1.
`MethodParameter(Constructor<?> constructor, int parameterIndex, int nestingLevel)`	Create a new MethodParameter for the given constructor.
`MethodParameter(Method method, int parameterIndex)`	Create a new `MethodParameter` for the given method, with nesting level 1.
`MethodParameter(Method method, int parameterIndex, int nestingLevel)`	Create a new `MethodParameter` for the given method.
`MethodParameter(MethodParameter original)`	Copy constructor, resulting in an independent MethodParameter object based on the same metadata and cache state that the original object was in.

Method Summary

All Methods Static Methods Instance Methods Concrete Methods
Modifier and Type	Method	Description
`protected <A extends Annotation> A`	`adaptAnnotation(A annotation)`	A template method to post-process a given annotation instance before returning it to the caller.
`protected Annotation[]`	`adaptAnnotationArray(Annotation[] annotations)`	A template method to post-process a given annotation array before returning it to the caller.
`MethodParameter`	`clone()`
`void`	`decreaseNestingLevel()`	Decrease this parameter's nesting level.
`boolean`	`equals(Object other)`
`static MethodParameter`	`forMethodOrConstructor(Object methodOrConstructor, int parameterIndex)`	Create a new MethodParameter for the given method or constructor.
`AnnotatedElement`	`getAnnotatedElement()`	Return the wrapped annotated element.
`Constructor<?>`	`getConstructor()`	Return the wrapped Constructor, if any.
`Class<?>`	`getContainingClass()`	Return the containing class for this method parameter.
`Class<?>`	`getDeclaringClass()`	Return the class that declares the underlying Method or Constructor.
`Type`	`getGenericParameterType()`	Return the generic type of the method/constructor parameter.
`Member`	`getMember()`	Return the wrapped member.
`Method`	`getMethod()`	Return the wrapped Method, if any.
`<A extends Annotation> A`	`getMethodAnnotation(Class<A> annotationType)`	Return the method/constructor annotation of the given type, if available.
`Annotation[]`	`getMethodAnnotations()`	Return the annotations associated with the target method/constructor itself.
`Type`	`getNestedGenericParameterType()`	Return the nested generic type of the method/constructor parameter.
`Class<?>`	`getNestedParameterType()`	Return the nested type of the method/constructor parameter.
`int`	`getNestingLevel()`	Return the nesting level of the target type (typically 1; e.g.
`<A extends Annotation> A`	`getParameterAnnotation(Class<A> annotationType)`	Return the parameter annotation of the given type, if available.
`Annotation[]`	`getParameterAnnotations()`	Return the annotations associated with the specific method/constructor parameter.
`int`	`getParameterIndex()`	Return the index of the method/constructor parameter.
`String`	`getParameterName()`	Return the name of the method/constructor parameter.
`Class<?>`	`getParameterType()`	Return the type of the method/constructor parameter.
`Integer`	`getTypeIndexForCurrentLevel()`	Return the type index for the current nesting level.
`Integer`	`getTypeIndexForLevel(int nestingLevel)`	Return the type index for the specified nesting level.
`int`	`hashCode()`
`<A extends Annotation> boolean`	`hasMethodAnnotation(Class<A> annotationType)`	Return whether the method/constructor is annotated with the given type.
`<A extends Annotation> boolean`	`hasParameterAnnotation(Class<A> annotationType)`	Return whether the parameter is declared with the given annotation type.
`boolean`	`hasParameterAnnotations()`	Return `true` if the parameter has at least one annotation, `false` if it has none.
`void`	`increaseNestingLevel()`	Increase this parameter's nesting level.
`void`	`initParameterNameDiscovery(ParameterNameDiscoverer parameterNameDiscoverer)`	Initialize parameter name discovery for this method parameter.
`boolean`	`isOptional()`	Return whether this method parameter is declared as optional in the form of Java 8's `Optional`.
`MethodParameter`	`nested()`	Return a variant of this `MethodParameter` which points to the same parameter but one nesting level deeper.
`MethodParameter`	`nestedIfOptional()`	Return a variant of this `MethodParameter` which points to the same parameter but one nesting level deeper in case of a `Optional` declaration.
`void`	`setTypeIndexForCurrentLevel(int typeIndex)`	Set the type index for the current nesting level.
`String`	`toString()`

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

- Constructor Detail
  - MethodParameter
```
public MethodParameter(Method method,
                       int parameterIndex)
```
    Create a new MethodParameter for the given method, with nesting level 1.
    Parameters:
    method - the Method to specify a parameter for
    parameterIndex - the index of the parameter: -1 for the method return type; 0 for the first method parameter; 1 for the second method parameter, etc.
  - MethodParameter
```
public MethodParameter(Method method,
                       int parameterIndex,
                       int nestingLevel)
```
    Create a new MethodParameter for the given method.
    Parameters:
    method - the Method to specify a parameter for
    parameterIndex - the index of the parameter: -1 for the method return type; 0 for the first method parameter; 1 for the second method parameter, etc.
    nestingLevel - the nesting level of the target type (typically 1; e.g. in case of a List of Lists, 1 would indicate the nested List, whereas 2 would indicate the element of the nested List)
  - MethodParameter
```
public MethodParameter(Constructor<?> constructor,
                       int parameterIndex)
```
    Create a new MethodParameter for the given constructor, with nesting level 1.
    Parameters:
    constructor - the Constructor to specify a parameter for
    parameterIndex - the index of the parameter
  - MethodParameter
```
public MethodParameter(Constructor<?> constructor,
                       int parameterIndex,
                       int nestingLevel)
```
    Create a new MethodParameter for the given constructor.
    Parameters:
    constructor - the Constructor to specify a parameter for
    parameterIndex - the index of the parameter
    nestingLevel - the nesting level of the target type (typically 1; e.g. in case of a List of Lists, 1 would indicate the nested List, whereas 2 would indicate the element of the nested List)
  - MethodParameter
```
public MethodParameter(MethodParameter original)
```
    Copy constructor, resulting in an independent MethodParameter object based on the same metadata and cache state that the original object was in.
    Parameters:
    original - the original MethodParameter object to copy from
- Method Detail
  - getMethod
```
public Method getMethod()
```
    Return the wrapped Method, if any.
    Note: Either Method or Constructor is available.
    Returns:
    the Method, or null if none
  - getConstructor
```
public Constructor<?> getConstructor()
```
    Return the wrapped Constructor, if any.
    Note: Either Method or Constructor is available.
    Returns:
    the Constructor, or null if none
  - getDeclaringClass
```
public Class<?> getDeclaringClass()
```
    Return the class that declares the underlying Method or Constructor.
  - getMember
```
public Member getMember()
```
    Return the wrapped member.
    Returns:
    the Method or Constructor as Member
  - getAnnotatedElement
```
public AnnotatedElement getAnnotatedElement()
```
    Return the wrapped annotated element.
    Note: This method exposes the annotations declared on the method/constructor itself (i.e. at the method/constructor level, not at the parameter level).
    Returns:
    the Method or Constructor as AnnotatedElement
  - getParameterIndex
```
public int getParameterIndex()
```
    Return the index of the method/constructor parameter.
    Returns:
    the parameter index (-1 in case of the return type)
  - increaseNestingLevel
```
public void increaseNestingLevel()
```
    Increase this parameter's nesting level.
    See Also:
    getNestingLevel()
  - decreaseNestingLevel
```
public void decreaseNestingLevel()
```
    Decrease this parameter's nesting level.
    See Also:
    getNestingLevel()
  - getNestingLevel
```
public int getNestingLevel()
```
    Return the nesting level of the target type (typically 1; e.g. in case of a List of Lists, 1 would indicate the nested List, whereas 2 would indicate the element of the nested List).
  - setTypeIndexForCurrentLevel
```
public void setTypeIndexForCurrentLevel(int typeIndex)
```
    Set the type index for the current nesting level.
    Parameters:
    typeIndex - the corresponding type index (or null for the default type index)
    See Also:
    getNestingLevel()
  - getTypeIndexForCurrentLevel
```
public Integer getTypeIndexForCurrentLevel()
```
    Return the type index for the current nesting level.
    Returns:
    the corresponding type index, or null if none specified (indicating the default type index)
    See Also:
    getNestingLevel()
  - getTypeIndexForLevel
```
public Integer getTypeIndexForLevel(int nestingLevel)
```
    Return the type index for the specified nesting level.
    Parameters:
    nestingLevel - the nesting level to check
    Returns:
    the corresponding type index, or null if none specified (indicating the default type index)
  - nested
```
public MethodParameter nested()
```
    Return a variant of this MethodParameter which points to the same parameter but one nesting level deeper. This is effectively the same as increaseNestingLevel(), just with an independent MethodParameter object (e.g. in case of the original being cached).
    Since:
    4.3
  - isOptional
```
public boolean isOptional()
```
    Return whether this method parameter is declared as optional in the form of Java 8's Optional.
    Since:
    4.3
  - nestedIfOptional
```
public MethodParameter nestedIfOptional()
```
    Return a variant of this MethodParameter which points to the same parameter but one nesting level deeper in case of a Optional declaration.
    Since:
    4.3
    See Also:
    isOptional(), nested()
  - getContainingClass
```
public Class<?> getContainingClass()
```
    Return the containing class for this method parameter.
    Returns:
    a specific containing class (potentially a subclass of the declaring class), or otherwise simply the declaring class itself
    See Also:
    getDeclaringClass()
  - getParameterType
```
public Class<?> getParameterType()
```
    Return the type of the method/constructor parameter.
    Returns:
    the parameter type (never null)
  - getGenericParameterType
```
public Type getGenericParameterType()
```
    Return the generic type of the method/constructor parameter.
    Returns:
    the parameter type (never null)
    Since:
    3.0
  - getNestedParameterType
```
public Class<?> getNestedParameterType()
```
    Return the nested type of the method/constructor parameter.
    Returns:
    the parameter type (never null)
    Since:
    3.1
    See Also:
    getNestingLevel()
  - getNestedGenericParameterType
```
public Type getNestedGenericParameterType()
```
    Return the nested generic type of the method/constructor parameter.
    Returns:
    the parameter type (never null)
    Since:
    4.2
    See Also:
    getNestingLevel()
  - getMethodAnnotations
```
public Annotation[] getMethodAnnotations()
```
    Return the annotations associated with the target method/constructor itself.
  - getMethodAnnotation
```
public <A extends Annotation> A getMethodAnnotation(Class<A> annotationType)
```
    Return the method/constructor annotation of the given type, if available.
    Parameters:
    annotationType - the annotation type to look for
    Returns:
    the annotation object, or null if not found
  - hasMethodAnnotation
```
public <A extends Annotation> boolean hasMethodAnnotation(Class<A> annotationType)
```
    Return whether the method/constructor is annotated with the given type.
    Parameters:
    annotationType - the annotation type to look for
    Since:
    4.3
    See Also:
    getMethodAnnotation(Class)
  - getParameterAnnotations
```
public Annotation[] getParameterAnnotations()
```
    Return the annotations associated with the specific method/constructor parameter.
  - hasParameterAnnotations
```
public boolean hasParameterAnnotations()
```
    Return true if the parameter has at least one annotation, false if it has none.
    See Also:
    getParameterAnnotations()
  - getParameterAnnotation
```
public <A extends Annotation> A getParameterAnnotation(Class<A> annotationType)
```
    Return the parameter annotation of the given type, if available.
    Parameters:
    annotationType - the annotation type to look for
    Returns:
    the annotation object, or null if not found
  - hasParameterAnnotation
```
public <A extends Annotation> boolean hasParameterAnnotation(Class<A> annotationType)
```
    Return whether the parameter is declared with the given annotation type.
    Parameters:
    annotationType - the annotation type to look for
    See Also:
    getParameterAnnotation(Class)
  - initParameterNameDiscovery
```
public void initParameterNameDiscovery(ParameterNameDiscoverer parameterNameDiscoverer)
```
    Initialize parameter name discovery for this method parameter.
    This method does not actually try to retrieve the parameter name at this point; it just allows discovery to happen when the application calls getParameterName() (if ever).
  - getParameterName
```
public String getParameterName()
```
    Return the name of the method/constructor parameter.
    Returns:
    the parameter name (may be null if no parameter name metadata is contained in the class file or no ParameterNameDiscoverer has been set to begin with)
  - adaptAnnotation
```
protected <A extends Annotation> A adaptAnnotation(A annotation)
```
    A template method to post-process a given annotation instance before returning it to the caller.
    The default implementation simply returns the given annotation as-is.
    Parameters:
    annotation - the annotation about to be returned
    Returns:
    the post-processed annotation (or simply the original one)
    Since:
    4.2
  - adaptAnnotationArray
```
protected Annotation[] adaptAnnotationArray(Annotation[] annotations)
```
    A template method to post-process a given annotation array before returning it to the caller.
    The default implementation simply returns the given annotation array as-is.
    Parameters:
    annotations - the annotation array about to be returned
    Returns:
    the post-processed annotation array (or simply the original one)
    Since:
    4.2
  - equals
```
public boolean equals(Object other)
```
    Overrides:
    equals in class Object
  - hashCode
```
public int hashCode()
```
    Overrides:
    hashCode in class Object
  - toString
```
public String toString()
```
    Overrides:
    toString in class Object
  - clone
```
public MethodParameter clone()
```
    Overrides:
    clone in class Object
  - forMethodOrConstructor
```
public static MethodParameter forMethodOrConstructor(Object methodOrConstructor,
                                                     int parameterIndex)
```
    Create a new MethodParameter for the given method or constructor.
    This is a convenience constructor for scenarios where a Method or Constructor reference is treated in a generic fashion.
    Parameters:
    methodOrConstructor - the Method or Constructor to specify a parameter for
    parameterIndex - the index of the parameter
    Returns:
    the corresponding MethodParameter instance

Class MethodParameter

Constructor Summary

Method Summary

Methods inherited from class java.lang.Object

Constructor Detail

MethodParameter

MethodParameter

MethodParameter

MethodParameter

MethodParameter

Method Detail

getMethod

getConstructor

getDeclaringClass

getMember

getAnnotatedElement

getParameterIndex

increaseNestingLevel

decreaseNestingLevel

getNestingLevel

setTypeIndexForCurrentLevel

getTypeIndexForCurrentLevel

getTypeIndexForLevel

nested

isOptional

nestedIfOptional

getContainingClass

getParameterType

getGenericParameterType

getNestedParameterType

getNestedGenericParameterType

getMethodAnnotations

getMethodAnnotation

hasMethodAnnotation

getParameterAnnotations

hasParameterAnnotations

getParameterAnnotation

hasParameterAnnotation

initParameterNameDiscovery

getParameterName

adaptAnnotation

adaptAnnotationArray

equals

hashCode

toString

clone

forMethodOrConstructor