Class MethodParameter
- 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. aMethod
orConstructor
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, Sebastien Deleuze, Phillip Webb
- 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 newMethodParameter
for the given method, with nesting level 1.MethodParameter(Method method, int parameterIndex, int nestingLevel)
Create a newMethodParameter
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 Deprecated Methods Modifier and Type Method Description protected <A extends Annotation>
AadaptAnnotation(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()
Deprecated.since 5.2 in favor of retaining the original MethodParameter and usingnested(Integer)
if nesting is requiredboolean
equals(Object other)
protected static int
findParameterIndex(Parameter parameter)
static MethodParameter
forExecutable(Executable executable, int parameterIndex)
Create a new MethodParameter for the given method or constructor.static MethodParameter
forMethodOrConstructor(Object methodOrConstructor, int parameterIndex)
Deprecated.as of 5.0, in favor offorExecutable(java.lang.reflect.Executable, int)
static MethodParameter
forParameter(Parameter parameter)
Create a new MethodParameter for the given parameter descriptor.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.Executable
getExecutable()
Return the wrapped executable.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>
AgetMethodAnnotation(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.Parameter
getParameter()
Return theParameter
descriptor for method/constructor parameter.<A extends Annotation>
AgetParameterAnnotation(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>
booleanhasMethodAnnotation(Class<A> annotationType)
Return whether the method/constructor is annotated with the given type.<A extends Annotation>
booleanhasParameterAnnotation(Class<A> annotationType)
Return whether the parameter is declared with the given annotation type.boolean
hasParameterAnnotations()
Returntrue
if the parameter has at least one annotation,false
if it has none.void
increaseNestingLevel()
Deprecated.since 5.2 in favor ofnested(Integer)
void
initParameterNameDiscovery(ParameterNameDiscoverer parameterNameDiscoverer)
Initialize parameter name discovery for this method parameter.boolean
isOptional()
Return whether this method indicates a parameter which is not required: either in the form of Java 8'sOptional
, any variant of a parameter-levelNullable
annotation (such as from JSR-305 or the FindBugs set of annotations), or a language-level nullable type declaration orContinuation
parameter in Kotlin.MethodParameter
nested()
Return a variant of thisMethodParameter
which points to the same parameter but one nesting level deeper.MethodParameter
nested(Integer typeIndex)
Return a variant of thisMethodParameter
which points to the same parameter but one nesting level deeper.MethodParameter
nestedIfOptional()
Return a variant of thisMethodParameter
which points to the same parameter but one nesting level deeper in case of aOptional
declaration.void
setTypeIndexForCurrentLevel(int typeIndex)
Deprecated.since 5.2 in favor ofwithTypeIndex(int)
String
toString()
MethodParameter
withContainingClass(Class<?> containingClass)
Return a variant of thisMethodParameter
which refers to the given containing class.MethodParameter
withTypeIndex(int typeIndex)
Return a variant of thisMethodParameter
with the type for the current level set to the specified value.
Constructor Detail
MethodParameter
public MethodParameter(Method method, int parameterIndex)
Create a newMethodParameter
for the given method, with nesting level 1.- Parameters:
method
- the Method to specify a parameter forparameterIndex
- 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 newMethodParameter
for the given method.- Parameters:
method
- the Method to specify a parameter forparameterIndex
- 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 forparameterIndex
- 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 forparameterIndex
- the index of the parameternestingLevel
- 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
@Nullable public Method getMethod()
Return the wrapped Method, if any.Note: Either Method or Constructor is available.
- Returns:
- the Method, or
null
if none
getConstructor
@Nullable 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
getExecutable
public Executable getExecutable()
Return the wrapped executable.- Returns:
- the Method or Constructor as Executable
- Since:
- 5.0
getParameter
public Parameter getParameter()
Return theParameter
descriptor for method/constructor parameter.- Since:
- 5.0
getParameterIndex
public int getParameterIndex()
Return the index of the method/constructor parameter.- Returns:
- the parameter index (-1 in case of the return type)
increaseNestingLevel
@Deprecated public void increaseNestingLevel()
Deprecated.since 5.2 in favor ofnested(Integer)
Increase this parameter's nesting level.- See Also:
getNestingLevel()
decreaseNestingLevel
@Deprecated public void decreaseNestingLevel()
Deprecated.since 5.2 in favor of retaining the original MethodParameter and usingnested(Integer)
if nesting is requiredDecrease 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).
withTypeIndex
public MethodParameter withTypeIndex(int typeIndex)
Return a variant of thisMethodParameter
with the type for the current level set to the specified value.- Parameters:
typeIndex
- the new type index- Since:
- 5.2
setTypeIndexForCurrentLevel
@Deprecated public void setTypeIndexForCurrentLevel(int typeIndex)
Deprecated.since 5.2 in favor ofwithTypeIndex(int)
Set the type index for the current nesting level.- Parameters:
typeIndex
- the corresponding type index (ornull
for the default type index)- See Also:
getNestingLevel()
getTypeIndexForCurrentLevel
@Nullable 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
@Nullable 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 thisMethodParameter
which points to the same parameter but one nesting level deeper.- Since:
- 4.3
nested
public MethodParameter nested(@Nullable Integer typeIndex)
Return a variant of thisMethodParameter
which points to the same parameter but one nesting level deeper.- Parameters:
typeIndex
- the type index for the new nesting level- Since:
- 5.2
isOptional
public boolean isOptional()
Return whether this method indicates a parameter which is not required: either in the form of Java 8'sOptional
, any variant of a parameter-levelNullable
annotation (such as from JSR-305 or the FindBugs set of annotations), or a language-level nullable type declaration orContinuation
parameter in Kotlin.- Since:
- 4.3
nestedIfOptional
public MethodParameter nestedIfOptional()
Return a variant of thisMethodParameter
which points to the same parameter but one nesting level deeper in case of aOptional
declaration.- Since:
- 4.3
- See Also:
isOptional()
,nested()
withContainingClass
public MethodParameter withContainingClass(@Nullable Class<?> containingClass)
Return a variant of thisMethodParameter
which refers to the given containing class.- Parameters:
containingClass
- a specific containing class (potentially a subclass of the declaring class, e.g. substituting a type variable)- Since:
- 5.2
- See Also:
getParameterType()
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
@Nullable 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()
Returntrue
if the parameter has at least one annotation,false
if it has none.- See Also:
getParameterAnnotations()
getParameterAnnotation
@Nullable 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(@Nullable 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
@Nullable 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 noParameterNameDiscoverer
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
clone
public MethodParameter clone()
forMethodOrConstructor
@Deprecated public static MethodParameter forMethodOrConstructor(Object methodOrConstructor, int parameterIndex)
Deprecated.as of 5.0, in favor offorExecutable(java.lang.reflect.Executable, int)
Create a new MethodParameter for the given method or constructor.This is a convenience factory method for scenarios where a Method or Constructor reference is treated in a generic fashion.
- Parameters:
methodOrConstructor
- the Method or Constructor to specify a parameter forparameterIndex
- the index of the parameter- Returns:
- the corresponding MethodParameter instance
forExecutable
public static MethodParameter forExecutable(Executable executable, int parameterIndex)
Create a new MethodParameter for the given method or constructor.This is a convenience factory method for scenarios where a Method or Constructor reference is treated in a generic fashion.
- Parameters:
executable
- the Method or Constructor to specify a parameter forparameterIndex
- the index of the parameter- Returns:
- the corresponding MethodParameter instance
- Since:
- 5.0
forParameter
public static MethodParameter forParameter(Parameter parameter)
Create a new MethodParameter for the given parameter descriptor.This is a convenience factory method for scenarios where a Java 8
Parameter
descriptor is already available.- Parameters:
parameter
- the parameter descriptor- Returns:
- the corresponding MethodParameter instance
- Since:
- 5.0
findParameterIndex
protected static int findParameterIndex(Parameter parameter)