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Java™ Platform Standard Ed. 6 |
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SUMMARY: NESTED | FIELD | CONSTR | METHOD | DETAIL: FIELD | CONSTR | METHOD |
java.lang.Object java.lang.reflect.AccessibleObject java.lang.reflect.Method
public final class Method
A Method
provides information about, and access to, a single method
on a class or interface. The reflected method may be a class method
or an instance method (including an abstract method).
A Method
permits widening conversions to occur when matching the
actual parameters to invoke with the underlying method's formal
parameters, but it throws an IllegalArgumentException
if a
narrowing conversion would occur.
Member
,
Class
,
Class.getMethods()
,
Class.getMethod(String, Class[])
,
Class.getDeclaredMethods()
,
Class.getDeclaredMethod(String, Class[])
Field Summary |
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Fields inherited from interface java.lang.reflect.Member |
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DECLARED, PUBLIC |
Method Summary | ||
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boolean |
equals(Object obj)
Compares this Method against the specified object. |
|
|
getAnnotation(Class<T> annotationClass)
Returns this element's annotation for the specified type if such an annotation is present, else null. |
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Annotation[] |
getDeclaredAnnotations()
Returns all annotations that are directly present on this element. |
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Class<?> |
getDeclaringClass()
Returns the Class object representing the class or interface
that declares the method represented by this Method object. |
|
Object |
getDefaultValue()
Returns the default value for the annotation member represented by this Method instance. |
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Class<?>[] |
getExceptionTypes()
Returns an array of Class objects that represent
the types of the exceptions declared to be thrown
by the underlying method
represented by this Method object. |
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Type[] |
getGenericExceptionTypes()
Returns an array of Type objects that represent the exceptions declared to be thrown by this Method object. |
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Type[] |
getGenericParameterTypes()
Returns an array of Type objects that represent the formal parameter types, in declaration order, of the method represented by this Method object. |
|
Type |
getGenericReturnType()
Returns a Type object that represents the formal return type of the method represented by this Method object. |
|
int |
getModifiers()
Returns the Java language modifiers for the method represented by this Method object, as an integer. |
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String |
getName()
Returns the name of the method represented by this Method
object, as a String . |
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Annotation[][] |
getParameterAnnotations()
Returns an array of arrays that represent the annotations on the formal parameters, in declaration order, of the method represented by this Method object. |
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Class<?>[] |
getParameterTypes()
Returns an array of Class objects that represent the formal
parameter types, in declaration order, of the method
represented by this Method object. |
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Class<?> |
getReturnType()
Returns a Class object that represents the formal return type
of the method represented by this Method object. |
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TypeVariable<Method>[] |
getTypeParameters()
Returns an array of TypeVariable objects that represent the type variables declared by the generic declaration represented by this GenericDeclaration object, in declaration order. |
|
int |
hashCode()
Returns a hashcode for this Method . |
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Object |
invoke(Object obj,
Object... args)
Invokes the underlying method represented by this Method
object, on the specified object with the specified parameters. |
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boolean |
isBridge()
Returns true if this method is a bridge method; returns false otherwise. |
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boolean |
isSynthetic()
Returns true if this method is a synthetic method; returns false otherwise. |
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boolean |
isVarArgs()
Returns true if this method was declared to take a variable number of arguments; returns false otherwise. |
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String |
toGenericString()
Returns a string describing this Method , including
type parameters. |
|
String |
toString()
Returns a string describing this Method . |
Methods inherited from class java.lang.reflect.AccessibleObject |
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getAnnotations, isAccessible, isAnnotationPresent, setAccessible, setAccessible |
Methods inherited from class java.lang.Object |
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clone, finalize, getClass, notify, notifyAll, wait, wait, wait |
Method Detail |
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public Class<?> getDeclaringClass()
Class
object representing the class or interface
that declares the method represented by this Method
object.
getDeclaringClass
in interface Member
public String getName()
Method
object, as a String
.
getName
in interface Member
public int getModifiers()
Method
object, as an integer. The Modifier
class should
be used to decode the modifiers.
getModifiers
in interface Member
Modifier
public TypeVariable<Method>[] getTypeParameters()
getTypeParameters
in interface GenericDeclaration
GenericSignatureFormatError
- if the generic
signature of this generic declaration does not conform to
the format specified in the Java Virtual Machine Specification,
3rd editionpublic Class<?> getReturnType()
Class
object that represents the formal return type
of the method represented by this Method
object.
public Type getGenericReturnType()
If the return type is a parameterized type, the Type object returned must accurately reflect the actual type parameters used in the source code.
If the return type is a type variable or a parameterized type, it is created. Otherwise, it is resolved.
GenericSignatureFormatError
- if the generic method signature does not conform to the format
specified in the Java Virtual Machine Specification, 3rd edition
TypeNotPresentException
- if the underlying method's
return type refers to a non-existent type declaration
MalformedParameterizedTypeException
- if the
underlying method's return typed refers to a parameterized
type that cannot be instantiated for any reasonpublic Class<?>[] getParameterTypes()
Class
objects that represent the formal
parameter types, in declaration order, of the method
represented by this Method
object. Returns an array of length
0 if the underlying method takes no parameters.
public Type[] getGenericParameterTypes()
If a formal parameter type is a parameterized type, the Type object returned for it must accurately reflect the actual type parameters used in the source code.
If a formal parameter type is a type variable or a parameterized type, it is created. Otherwise, it is resolved.
GenericSignatureFormatError
- if the generic method signature does not conform to the format
specified in the Java Virtual Machine Specification, 3rd edition
TypeNotPresentException
- if any of the parameter
types of the underlying method refers to a non-existent type
declaration
MalformedParameterizedTypeException
- if any of
the underlying method's parameter types refer to a parameterized
type that cannot be instantiated for any reasonpublic Class<?>[] getExceptionTypes()
Class
objects that represent
the types of the exceptions declared to be thrown
by the underlying method
represented by this Method
object. Returns an array of length
0 if the method declares no exceptions in its throws
clause.
public Type[] getGenericExceptionTypes()
If an exception type is a parameterized type, the Type object returned for it must accurately reflect the actual type parameters used in the source code.
If an exception type is a type variable or a parameterized type, it is created. Otherwise, it is resolved.
GenericSignatureFormatError
- if the generic method signature does not conform to the format
specified in the Java Virtual Machine Specification, 3rd edition
TypeNotPresentException
- if the underlying method's
throws clause refers to a non-existent type declaration
MalformedParameterizedTypeException
- if
the underlying method's throws clause refers to a
parameterized type that cannot be instantiated for any reasonpublic boolean equals(Object obj)
Method
against the specified object. Returns
true if the objects are the same. Two Methods
are the same if
they were declared by the same class and have the same name
and formal parameter types and return type.
equals
in class Object
obj
- the reference object with which to compare.
true
if this object is the same as the obj
argument; false
otherwise.Object.hashCode()
,
Hashtable
public int hashCode()
Method
. The hashcode is computed
as the exclusive-or of the hashcodes for the underlying
method's declaring class name and the method's name.
hashCode
in class Object
Object.equals(java.lang.Object)
,
Hashtable
public String toString()
Method
. The string is
formatted as the method access modifiers, if any, followed by
the method return type, followed by a space, followed by the
class declaring the method, followed by a period, followed by
the method name, followed by a parenthesized, comma-separated
list of the method's formal parameter types. If the method
throws checked exceptions, the parameter list is followed by a
space, followed by the word throws followed by a
comma-separated list of the thrown exception types.
For example:
public boolean java.lang.Object.equals(java.lang.Object)
The access modifiers are placed in canonical order as specified by "The Java Language Specification". This is public, protected or private first, and then other modifiers in the following order: abstract, static, final, synchronized, native.
toString
in class Object
public String toGenericString()
Method
, including
type parameters. The string is formatted as the method access
modifiers, if any, followed by an angle-bracketed
comma-separated list of the method's type parameters, if any,
followed by the method's generic return type, followed by a
space, followed by the class declaring the method, followed by
a period, followed by the method name, followed by a
parenthesized, comma-separated list of the method's generic
formal parameter types. A space is used to separate access
modifiers from one another and from the type parameters or
return type. If there are no type parameters, the type
parameter list is elided; if the type parameter list is
present, a space separates the list from the class name. If
the method is declared to throw exceptions, the parameter list
is followed by a space, followed by the word throws followed by
a comma-separated list of the generic thrown exception types.
If there are no type parameters, the type parameter list is
elided.
The access modifiers are placed in canonical order as specified by "The Java Language Specification". This is public, protected or private first, and then other modifiers in the following order: abstract, static, final, synchronized native.
Method
,
include type parameterspublic Object invoke(Object obj, Object... args) throws IllegalAccessException, IllegalArgumentException, InvocationTargetException
Method
object, on the specified object with the specified parameters.
Individual parameters are automatically unwrapped to match
primitive formal parameters, and both primitive and reference
parameters are subject to method invocation conversions as
necessary.
If the underlying method is static, then the specified obj
argument is ignored. It may be null.
If the number of formal parameters required by the underlying method is
0, the supplied args
array may be of length 0 or null.
If the underlying method is an instance method, it is invoked using dynamic method lookup as documented in The Java Language Specification, Second Edition, section 15.12.4.4; in particular, overriding based on the runtime type of the target object will occur.
If the underlying method is static, the class that declared the method is initialized if it has not already been initialized.
If the method completes normally, the value it returns is returned to the caller of invoke; if the value has a primitive type, it is first appropriately wrapped in an object. However, if the value has the type of an array of a primitive type, the elements of the array are not wrapped in objects; in other words, an array of primitive type is returned. If the underlying method return type is void, the invocation returns null.
obj
- the object the underlying method is invoked fromargs
- the arguments used for the method call
obj
with parameters
args
IllegalAccessException
- if this Method
object
enforces Java language access control and the underlying
method is inaccessible.
IllegalArgumentException
- if the method is an
instance method and the specified object argument
is not an instance of the class or interface
declaring the underlying method (or of a subclass
or implementor thereof); if the number of actual
and formal parameters differ; if an unwrapping
conversion for primitive arguments fails; or if,
after possible unwrapping, a parameter value
cannot be converted to the corresponding formal
parameter type by a method invocation conversion.
InvocationTargetException
- if the underlying method
throws an exception.
NullPointerException
- if the specified object is null
and the method is an instance method.
ExceptionInInitializerError
- if the initialization
provoked by this method fails.public boolean isBridge()
public boolean isVarArgs()
public boolean isSynthetic()
isSynthetic
in interface Member
public <T extends Annotation> T getAnnotation(Class<T> annotationClass)
AnnotatedElement
getAnnotation
in interface AnnotatedElement
getAnnotation
in class AccessibleObject
annotationClass
- the Class object corresponding to the
annotation type
NullPointerException
- if the given annotation class is nullpublic Annotation[] getDeclaredAnnotations()
AnnotatedElement
getDeclaredAnnotations
in interface AnnotatedElement
getDeclaredAnnotations
in class AccessibleObject
public Object getDefaultValue()
TypeNotPresentException
- if the annotation is of type
Class
and no definition can be found for the
default class value.public Annotation[][] getParameterAnnotations()
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Java™ Platform Standard Ed. 6 |
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Copyright 2006 Sun Microsystems, Inc. All rights reserved. Use is subject to license terms. Also see the documentation redistribution policy.