org.springframework.core

Class MethodParameter

java.lang.Object

org.springframework.core.MethodParameter

Direct Known Subclasses:

SynthesizingMethodParameter

public class MethodParameter
extends java.lang.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:

GenericCollectionTypeResolver, SynthesizingMethodParameter

Field Summary

Fields

Modifier and Type	Field and Description
private java.lang.reflect.Constructor<?>	constructor
private java.lang.Class<?>	containingClass
private java.lang.reflect.Type	genericParameterType
private java.lang.reflect.Method	method
private int	nestingLevel
private java.lang.annotation.Annotation[]	parameterAnnotations
private int	parameterIndex
private java.lang.String	parameterName
private ParameterNameDiscoverer	parameterNameDiscoverer
private java.lang.Class<?>	parameterType
(package private) java.util.Map<java.lang.Integer,java.lang.Integer>	typeIndexesPerLevel Map from Integer level to Integer type index

Constructor Summary

Constructors

Constructor and Description
MethodParameter(java.lang.reflect.Constructor<?> constructor, int parameterIndex) Create a new MethodParameter for the given constructor, with nesting level 1.
MethodParameter(java.lang.reflect.Constructor<?> constructor, int parameterIndex, int nestingLevel) Create a new MethodParameter for the given constructor.
MethodParameter(java.lang.reflect.Method method, int parameterIndex) Create a new MethodParameter for the given method, with nesting level 1.
MethodParameter(java.lang.reflect.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

Modifier and Type	Method and Description
protected <A extends java.lang.annotation.Annotation> A	adaptAnnotation(A annotation) A template method to post-process a given annotation instance before returning it to the caller.
protected java.lang.annotation.Annotation[]	adaptAnnotationArray(java.lang.annotation.Annotation[] annotations) A template method to post-process a given annotation array before returning it to the caller.
void	decreaseNestingLevel() Decrease this parameter's nesting level.
boolean	equals(java.lang.Object other)
static MethodParameter	forMethodOrConstructor(java.lang.Object methodOrConstructor, int parameterIndex) Create a new MethodParameter for the given method or constructor.
java.lang.reflect.AnnotatedElement	getAnnotatedElement() Returns the wrapped annotated element.
java.lang.reflect.Constructor<?>	getConstructor() Return the wrapped Constructor, if any.
java.lang.Class<?>	getContainingClass()
java.lang.Class<?>	getDeclaringClass() Return the class that declares the underlying Method or Constructor.
java.lang.reflect.Type	getGenericParameterType() Return the generic type of the method/constructor parameter.
java.lang.reflect.Member	getMember() Returns the wrapped member.
java.lang.reflect.Method	getMethod() Return the wrapped Method, if any.
<A extends java.lang.annotation.Annotation> A	getMethodAnnotation(java.lang.Class<A> annotationType) Return the method/constructor annotation of the given type, if available.
java.lang.annotation.Annotation[]	getMethodAnnotations() Return the annotations associated with the target method/constructor itself.
java.lang.reflect.Type	getNestedGenericParameterType() Return the nested generic type of the method/constructor parameter.
java.lang.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.
<T extends java.lang.annotation.Annotation> T	getParameterAnnotation(java.lang.Class<T> annotationType) Return the parameter annotation of the given type, if available.
java.lang.annotation.Annotation[]	getParameterAnnotations() Return the annotations associated with the specific method/constructor parameter.
int	getParameterIndex() Return the index of the method/constructor parameter.
java.lang.String	getParameterName() Return the name of the method/constructor parameter.
java.lang.Class<?>	getParameterType() Return the type of the method/constructor parameter.
private java.util.Map<java.lang.Integer,java.lang.Integer>	getTypeIndexesPerLevel() Obtain the (lazily constructed) type-indexes-per-level Map.
java.lang.Integer	getTypeIndexForCurrentLevel() Return the type index for the current nesting level.
java.lang.Integer	getTypeIndexForLevel(int nestingLevel) Return the type index for the specified nesting level.
int	hashCode()
<T extends java.lang.annotation.Annotation> boolean	hasParameterAnnotation(java.lang.Class<T> annotationType) Return true if the parameter has the given annotation type, and false if it doesn't.
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.
(package private) void	setContainingClass(java.lang.Class<?> containingClass) Set a containing class to resolve the parameter type against.
(package private) void	setParameterType(java.lang.Class<?> parameterType) Set a resolved (generic) parameter type.
void	setTypeIndexForCurrentLevel(int typeIndex) Set the type index for the current nesting level.

Methods inherited from class java.lang.Object

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

Field Detail

method

private final java.lang.reflect.Method method

constructor

private final java.lang.reflect.Constructor<?> constructor

parameterIndex

private final int parameterIndex

nestingLevel

private int nestingLevel

typeIndexesPerLevel

java.util.Map<java.lang.Integer,java.lang.Integer> typeIndexesPerLevel

Map from Integer level to Integer type index

containingClass

private volatile java.lang.Class<?> containingClass

parameterType

private volatile java.lang.Class<?> parameterType

genericParameterType

private volatile java.lang.reflect.Type genericParameterType

parameterAnnotations

private volatile java.lang.annotation.Annotation[] parameterAnnotations

parameterNameDiscoverer

private volatile ParameterNameDiscoverer parameterNameDiscoverer

parameterName

private volatile java.lang.String parameterName

Constructor Detail

MethodParameter

public MethodParameter(java.lang.reflect.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(java.lang.reflect.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(java.lang.reflect.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(java.lang.reflect.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 java.lang.reflect.Method getMethod()

Return the wrapped Method, if any.

Note: Either Method or Constructor is available.

Returns:

the Method, or null if none

getConstructor

public java.lang.reflect.Constructor<?> getConstructor()

Return the wrapped Constructor, if any.

Note: Either Method or Constructor is available.

Returns:

the Constructor, or null if none

getMember

public java.lang.reflect.Member getMember()

Returns the wrapped member.

Returns:

the Method or Constructor as Member

getAnnotatedElement

public java.lang.reflect.AnnotatedElement getAnnotatedElement()

Returns the wrapped annotated element.

Returns:

the Method or Constructor as AnnotatedElement

getDeclaringClass

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

Return the class that declares the underlying Method or Constructor.

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 java.lang.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 java.lang.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)

getTypeIndexesPerLevel

private java.util.Map<java.lang.Integer,java.lang.Integer> getTypeIndexesPerLevel()

Obtain the (lazily constructed) type-indexes-per-level Map.

setContainingClass

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

Set a containing class to resolve the parameter type against.

getContainingClass

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

setParameterType

void setParameterType(java.lang.Class<?> parameterType)

Set a resolved (generic) parameter type.

getParameterType

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

Return the type of the method/constructor parameter.

Returns:

the parameter type (never null)

getGenericParameterType

public java.lang.reflect.Type getGenericParameterType()

Return the generic type of the method/constructor parameter.

Returns:

the parameter type (never null)

Since:

3.0

getNestedParameterType

public java.lang.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 java.lang.reflect.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 java.lang.annotation.Annotation[] getMethodAnnotations()

Return the annotations associated with the target method/constructor itself.

getMethodAnnotation

public <A extends java.lang.annotation.Annotation> A getMethodAnnotation(java.lang.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

getParameterAnnotations

public java.lang.annotation.Annotation[] getParameterAnnotations()

Return the annotations associated with the specific method/constructor parameter.

getParameterAnnotation

public <T extends java.lang.annotation.Annotation> T getParameterAnnotation(java.lang.Class<T> 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

hasParameterAnnotations

public boolean hasParameterAnnotations()

Return true if the parameter has at least one annotation, false if it has none.

hasParameterAnnotation

public <T extends java.lang.annotation.Annotation> boolean hasParameterAnnotation(java.lang.Class<T> annotationType)

Return true if the parameter has the given annotation type, and false if it doesn't.

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 java.lang.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 java.lang.annotation.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 java.lang.annotation.Annotation[] adaptAnnotationArray(java.lang.annotation.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(java.lang.Object other)

Overrides:

equals in class java.lang.Object

hashCode

public int hashCode()

Overrides:

hashCode in class java.lang.Object

forMethodOrConstructor

public static MethodParameter forMethodOrConstructor(java.lang.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