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.

Used by GenericCollectionTypeResolver, BeanWrapperImpl and AbstractBeanFactory.

Note that this class does not depend on JDK 1.5 API artifacts, in order to remain compatible with JDK 1.4. Concrete generic type resolution via JDK 1.5 API happens in GenericCollectionTypeResolver only.

Since:

2.0

Author:

Juergen Hoeller, Rob Harrop

See Also:

GenericCollectionTypeResolver

Constructor Summary

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

void	decreaseNestingLevel() Decrease this parameter's nesting level.
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.
Method	getMethod() Return the wrapped Method, if any.
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).
Object[]	getParameterAnnotations() Return the annotations associated with the 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.
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, equals, finalize, getClass, hashCode, 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

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

getParameterIndex

public int getParameterIndex()

Return the index of the method/constructor parameter.

Returns:

the parameter index (never negative)

getParameterType

public Class getParameterType()

Return the type of the method/constructor parameter.

Returns:

the parameter type (never null)

getParameterAnnotations

public Object[] getParameterAnnotations()

Return the annotations associated with the method/constructor parameter.

Returns:

the parameter annotations, or null if there is no annotation support (on JDK < 1.5). The return value is an Object array instead of an Annotation array simply for compatibility with older JDKs; feel free to cast it to Annotation[] on JDK 1.5 or higher.

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)

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