public
final
class
Method
extends AccessibleObject
implements
GenericDeclaration,
Member
java.lang.Object | ||
↳ | java.lang.reflect.AccessibleObject | |
↳ | java.lang.reflect.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.
See also:
Inherited constants |
---|
From
interface
java.lang.reflect.Member
|
Fields | |
---|---|
protected
int |
accessFlags
Bits encoding access (e.g. |
protected
Class<?> |
declaringClass
Method's declaring class |
protected
Class<?> |
declaringClassOfOverriddenMethod
Overriden method's declaring class (same as declaringClass unless declaringClass is a proxy class) |
protected
int |
dexMethodIndex
The method index of this method within its defining dex file |
Public methods | |
---|---|
boolean
|
equals(Object obj)
Compares this |
<T extends Annotation>
T
|
getAnnotation(Class<T> annotationClass)
Returns this element's annotation for the specified type if such an annotation is present, else null. |
<A extends Annotation>
A
|
getAnnotation(Class<A> annotationType)
Returns this element's annotation for the specified type if such an annotation is present, else null. |
Annotation[]
|
getAnnotations()
Returns all annotations present on this element. |
Annotation[]
|
getDeclaredAnnotations()
Returns all annotations that are directly present on this element. |
Class<?>
|
getDeclaringClass()
Returns the |
Object
|
getDefaultValue()
Returns the default value for the annotation member represented by
this |
Class[]<?>
|
getExceptionTypes()
Returns an array of |
Type[]
|
getGenericExceptionTypes()
Returns an array of |
Type[]
|
getGenericParameterTypes()
Returns an array of |
Type
|
getGenericReturnType()
Returns a |
int
|
getModifiers()
Returns the Java language modifiers for the method represented
by this |
String
|
getName()
Returns the name of the method represented by this |
Annotation[][]
|
getParameterAnnotations()
Returns an array of arrays that represent the annotations on the formal
parameters, in declaration order, of the method represented by
this |
Class[]<?>
|
getParameterTypes()
Returns an array of |
Class<?>
|
getReturnType()
Returns a |
TypeVariable[]<Method>
|
getTypeParameters()
Returns an array of |
int
|
hashCode()
Returns a hashcode for this |
Object
|
invoke(Object receiver, Object... args)
Invokes the underlying method represented by this |
boolean
|
isAnnotationPresent(Class<? extends Annotation> annotationType)
|
boolean
|
isBridge()
Returns |
boolean
|
isDefault()
Returns |
boolean
|
isSynthetic()
Returns |
boolean
|
isVarArgs()
Returns |
String
|
toGenericString()
Returns a string describing this |
String
|
toString()
Returns a string describing this |
Protected methods | |
---|---|
int
|
compareParameters(Class[]<?> params)
|
boolean
|
equalMethodParameters(Class[]<?> params)
|
Inherited methods | |
---|---|
From
class
java.lang.reflect.AccessibleObject
| |
From
class
java.lang.Object
| |
From
interface
java.lang.reflect.AnnotatedElement
| |
From
interface
java.lang.reflect.GenericDeclaration
| |
From
interface
java.lang.reflect.Member
|
int accessFlags
Bits encoding access (e.g. public, private) as well as other runtime specific flags
Class<?> declaringClassOfOverriddenMethod
Overriden method's declaring class (same as declaringClass unless declaringClass is a proxy class)
int dexMethodIndex
The method index of this method within its defining dex file
boolean equals (Object obj)
Compares this 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.
Parameters | |
---|---|
obj |
Object :
the reference object with which to compare. |
Returns | |
---|---|
boolean |
true if this object is the same as the obj
argument; false otherwise. |
T getAnnotation (Class<T> annotationClass)
Returns this element's annotation for the specified type if such an annotation is present, else null.
Parameters | |
---|---|
annotationClass |
Class :
the Class object corresponding to the
annotation type |
Returns | |
---|---|
T |
this element's annotation for the specified annotation type if present on this element, else null |
A getAnnotation (Class<A> annotationType)
Returns this element's annotation for the specified type if such an annotation is present, else null.
Parameters | |
---|---|
annotationType |
Class :
the Class object corresponding to the
annotation type |
Returns | |
---|---|
A |
this element's annotation for the specified annotation type if present on this element, else null |
Throws | |
---|---|
NullPointerException |
Annotation[] getAnnotations ()
Returns all annotations present on this element. (Returns an array of length zero if this element has no annotations.) The caller of this method is free to modify the returned array; it will have no effect on the arrays returned to other callers.
Returns | |
---|---|
Annotation[] |
all annotations present on this element |
Annotation[] getDeclaredAnnotations ()
Returns all annotations that are directly present on this element. Unlike the other methods in this interface, this method ignores inherited annotations. (Returns an array of length zero if no annotations are directly present on this element.) The caller of this method is free to modify the returned array; it will have no effect on the arrays returned to other callers.
Returns | |
---|---|
Annotation[] |
All annotations directly present on this element |
Class<?> getDeclaringClass ()
Returns the Class
object representing the class or interface
that declares the method represented by this Method
object.
Returns | |
---|---|
Class<?> |
Object getDefaultValue ()
Returns the default value for the annotation member represented by
this Method
instance. If the member is of a primitive type,
an instance of the corresponding wrapper type is returned. Returns
null if no default is associated with the member, or if the method
instance does not represent a declared member of an annotation type.
Returns | |
---|---|
Object |
the default value for the annotation member represented
by this Method instance. |
Throws | |
---|---|
TypeNotPresentException |
if the annotation is of type
Class and no definition can be found for the
default class value. |
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. Returns an array of length
0 if the method declares no exceptions in its throws
clause.
Returns | |
---|---|
Class[]<?> |
the exception types declared as being thrown by the method this object represents |
Type[] getGenericExceptionTypes ()
Returns an array of Type
objects that represent the
exceptions declared to be thrown by this Method
object.
Returns an array of length 0 if the underlying method declares
no exceptions in its throws
clause.
If an exception type is a type variable or a parameterized type, it is created. Otherwise, it is resolved.
Returns | |
---|---|
Type[] |
an array of Types that represent the exception types thrown by the underlying method |
Throws | |
---|---|
GenericSignatureFormatError |
if the generic method signature does not conform to the format specified in The Java™ Virtual Machine Specification |
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 reason |
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. Returns an array of length 0 if the
underlying method takes no parameters.
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.
Returns | |
---|---|
Type[] |
an array of Types that represent the formal parameter types of the underlying method, in declaration order |
Throws | |
---|---|
GenericSignatureFormatError |
if the generic method signature does not conform to the format specified in The Java™ Virtual Machine Specification |
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 reason |
Type getGenericReturnType ()
Returns a Type
object that represents the formal return
type of the method represented by this Method
object.
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.
Returns | |
---|---|
Type |
a Type object that represents the formal return
type of the underlying method |
Throws | |
---|---|
GenericSignatureFormatError |
if the generic method signature does not conform to the format specified in The Java™ Virtual Machine Specification |
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 reason |
int getModifiers ()
Returns the Java language modifiers for the method represented
by this Method
object, as an integer. The Modifier
class should
be used to decode the modifiers.
Returns | |
---|---|
int |
See also:
String getName ()
Returns the name of the method represented by this Method
object, as a String
.
Returns | |
---|---|
String |
the name of this method |
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. (Returns an array of length zero if the
underlying method is parameterless. If the method has one or more
parameters, a nested array of length zero is returned for each parameter
with no annotations.) The annotation objects contained in the returned
arrays are serializable. The caller of this method is free to modify
the returned arrays; it will have no effect on the arrays returned to
other callers.
Returns | |
---|---|
Annotation[][] |
an array of arrays that represent the annotations on the formal parameters, in declaration order, of the method represented by this Method object |
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. Returns an array of length
0 if the underlying method takes no parameters.
Returns | |
---|---|
Class[]<?> |
the parameter types for the method this object represents |
Class<?> getReturnType ()
Returns a Class
object that represents the formal return type
of the method represented by this Method
object.
Returns | |
---|---|
Class<?> |
the return type for the method this object represents |
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. Returns an
array of length 0 if the underlying generic declaration declares no type
variables.
Returns | |
---|---|
TypeVariable[]<Method> |
an array of TypeVariable objects that represent
the type variables declared by this generic declaration |
Throws | |
---|---|
GenericSignatureFormatError |
if the generic signature of this generic declaration does not conform to the format specified in The Java™ Virtual Machine Specification |
int hashCode ()
Returns a hashcode for this 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.
Returns | |
---|---|
int |
a hash code value for this object. |
Object invoke (Object receiver, Object... args)
Invokes the underlying method represented by this 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.
Parameters | |
---|---|
receiver |
Object :
the object the underlying method is invoked from |
args |
Object :
the arguments used for the method call |
Returns | |
---|---|
Object |
the result of dispatching the method represented by
this object on obj with parameters
args |
Throws | |
---|---|
IllegalAccessException |
if this Method object
is enforcing 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. |
boolean isAnnotationPresent (Class<? extends Annotation> annotationType)
Parameters | |
---|---|
annotationType |
Class
|
Returns | |
---|---|
boolean |
boolean isBridge ()
Returns true
if this method is a bridge
method; returns false
otherwise.
Returns | |
---|---|
boolean |
true if and only if this method is a bridge method as defined by the Java Language Specification. |
boolean isDefault ()
Returns true
if this method is a default method; returns false
otherwise.
Returns | |
---|---|
boolean |
boolean isSynthetic ()
Returns true
if this method is a synthetic
method; returns false
otherwise.
Returns | |
---|---|
boolean |
true if and only if this method is a synthetic method as defined by the Java Language Specification. |
boolean isVarArgs ()
Returns true
if this method was declared to take
a variable number of arguments; returns false
otherwise.
Returns | |
---|---|
boolean |
true if an only if this method was declared to
take a variable number of arguments. |
String toGenericString ()
Returns a string describing this 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.
If this method was declared to take a variable number of
arguments, instead of denoting the last parameter as
"Type[]", it is denoted as
"Type...".
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
, strictfp
.
Returns | |
---|---|
String |
a string describing this Method ,
include type parameters |
String toString ()
Returns a string describing this 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
, strictfp
.
Returns | |
---|---|
String |
a string representation of the object. |
boolean equalMethodParameters (Class[]<?> params)
Parameters | |
---|---|
params |
Class
|
Returns | |
---|---|
boolean |