org.springframework.core

Class MethodParameter

java.lang.Object

org.springframework.core.MethodParameter

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.

Since:

2.0

Author:

Juergen Hoeller, Rob Harrop, Andy Clement

See Also:

GenericCollectionTypeResolver

Constructor Summary

Constructors

Constructor and 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

Methods

Modifier and Type	Method and Description
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.
Constructor<?>	getConstructor() Return the wrapped Constructor, if any.
Class<?>	getDeclaringClass() Return the class that declares the underlying Method or Constructor.
Type	getGenericParameterType() Return the generic type of the method/constructor parameter.
Method	getMethod() Return the wrapped Method, if any.
<T extends Annotation> T	getMethodAnnotation(Class<T> annotationType) Return the method/constructor annotation of the given type, if available.
Annotation[]	getMethodAnnotations() Return the annotations associated with the target method/constructor itself.
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 Annotation> T	getParameterAnnotation(Class<T> 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()
<T extends Annotation> boolean	hasParameterAnnotation(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.
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

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.

getParameterIndex

public int getParameterIndex()

Return the index of the method/constructor parameter.

Returns:

the parameter index (-1 in case of the return type)

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()

getMethodAnnotations

public Annotation[] getMethodAnnotations()

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

getMethodAnnotation

public <T extends Annotation> T getMethodAnnotation(Class<T> 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 Annotation[] getParameterAnnotations()

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

getParameterAnnotation

public <T extends Annotation> T getParameterAnnotation(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 Annotation> boolean hasParameterAnnotation(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 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)

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)

equals

public boolean equals(Object other)

Overrides:

equals in class Object

hashCode

public int hashCode()

Overrides:

hashCode 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