Class Invokable<T,R>
- java.lang.Object
-
- com.google.common.reflect.Invokable<T,R>
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- Type Parameters:
T
- the type that owns this method or constructor.R
- the return type of (or supertype thereof) the method or the declaring type of the constructor.
- All Implemented Interfaces:
AnnotatedElement
,Member
@Beta public abstract class Invokable<T,R> extends Object implements AnnotatedElement, Member
Wrapper around either aMethod
or aConstructor
. Convenience API is provided to make common reflective operation easier to deal with, such asisPublic()
,getParameters()
etc.In addition to convenience methods,
TypeToken.method(java.lang.reflect.Method)
andTypeToken.constructor(java.lang.reflect.Constructor<?>)
will resolve the type parameters of the method or constructor in the context of the owner type, which may be a subtype of the declaring class. For example:Method getMethod = List.class.getMethod("get", int.class); Invokable<List<String>, ?> invokable = new TypeToken<List<String>>() {}.method(getMethod); assertEquals(TypeToken.of(String.class), invokable.getReturnType()); // Not Object.class! assertEquals(new TypeToken<List<String>>() {}, invokable.getOwnerType());
Note: earlier versions of this class inherited from
AccessibleObject
andGenericDeclaration
. Since version 31.0 that is no longer the case. However, most methods from those types are present with the same signature in this class.- Since:
- 14.0 (no longer implements
AccessibleObject
orGenericDeclaration
since 31.0) - Author:
- Ben Yu
-
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Method Summary
All Methods Static Methods Instance Methods Abstract Methods Concrete Methods Modifier and Type Method Description boolean
equals(Object obj)
Indicates whether some other object is "equal to" this one.static <T> Invokable<T,T>
from(Constructor<T> constructor)
ReturnsInvokable
ofconstructor
.static Invokable<?,Object>
from(Method method)
ReturnsInvokable
ofmethod
.abstract AnnotatedType
getAnnotatedReturnType()
<A extends Annotation>
AgetAnnotation(Class<A> annotationClass)
Returns this element's annotation for the specified type if such an annotation is present, else null.Annotation[]
getAnnotations()
Returns annotations that are present on this element.Annotation[]
getDeclaredAnnotations()
Returns annotations that are directly present on this element.Class<? super T>
getDeclaringClass()
Returns the Class object representing the class or interface that declares the member or constructor represented by this Member.ImmutableList<TypeToken<? extends Throwable>>
getExceptionTypes()
Returns all declared exception types of thisInvokable
.int
getModifiers()
Returns the Java language modifiers for the member or constructor represented by this Member, as an integer.String
getName()
Returns the simple name of the underlying member or constructor represented by this Member.TypeToken<T>
getOwnerType()
Returns the type ofT
.ImmutableList<Parameter>
getParameters()
Returns all declared parameters of thisInvokable
.TypeToken<? extends R>
getReturnType()
Returns the return type of thisInvokable
.abstract TypeVariable<?>[]
getTypeParameters()
int
hashCode()
Returns a hash code value for the object.R
invoke(T receiver, @Nullable Object... args)
Invokes withreceiver
as 'this' andargs
passed to the underlying method and returns the return value; or calls the underlying constructor withargs
and returns the constructed instance.boolean
isAbstract()
Returns true if the method is abstract.boolean
isAccessible()
boolean
isAnnotationPresent(Class<? extends Annotation> annotationClass)
Returns true if an annotation for the specified type is present on this element, else false.boolean
isFinal()
Returnstrue
if this method is final, perModifier.isFinal(getModifiers())
.boolean
isNative()
Returns true if the element is native.abstract boolean
isOverridable()
Returnstrue
if this is an overridable method.boolean
isPackagePrivate()
Returns true if the element is package-private.boolean
isPrivate()
Returns true if the element is private.boolean
isProtected()
Returns true if the element is protected.boolean
isPublic()
Returns true if the element is public.boolean
isStatic()
Returns true if the element is static.boolean
isSynchronized()
Returns true if the method is synchronized.boolean
isSynthetic()
Returnstrue
if this member was introduced by the compiler; returnsfalse
otherwise.abstract boolean
isVarArgs()
Returnstrue
if this was declared to take a variable number of arguments.<R1 extends R>
Invokable<T,R1>returning(TypeToken<R1> returnType)
Explicitly specifies the return type of thisInvokable
.<R1 extends R>
Invokable<T,R1>returning(Class<R1> returnType)
Explicitly specifies the return type of thisInvokable
.void
setAccessible(boolean flag)
String
toString()
Returns a string representation of the object.boolean
trySetAccessible()
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Methods inherited from class java.lang.Object
clone, finalize, getClass, notify, notifyAll, wait, wait, wait
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Methods inherited from interface java.lang.reflect.AnnotatedElement
getAnnotationsByType, getDeclaredAnnotation, getDeclaredAnnotationsByType
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-
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Method Detail
-
from
public static <T> Invokable<T,T> from(Constructor<T> constructor)
ReturnsInvokable
ofconstructor
.
-
isAnnotationPresent
public final boolean isAnnotationPresent(Class<? extends Annotation> annotationClass)
Description copied from interface:java.lang.reflect.AnnotatedElement
Returns true if an annotation for the specified type is present on this element, else false. This method is designed primarily for convenient access to marker annotations.The truth value returned by this method is equivalent to:
getAnnotation(annotationClass) != null
The body of the default method is specified to be the code above.
- Specified by:
isAnnotationPresent
in interfaceAnnotatedElement
- Parameters:
annotationClass
- the Class object corresponding to the annotation type- Returns:
- true if an annotation for the specified annotation type is present on this element, else false
-
getAnnotation
@CheckForNull public final <A extends Annotation> A getAnnotation(Class<A> annotationClass)
Description copied from interface:java.lang.reflect.AnnotatedElement
Returns this element's annotation for the specified type if such an annotation is present, else null.- Specified by:
getAnnotation
in interfaceAnnotatedElement
- Type Parameters:
A
- the type of the annotation to query for and return if present- Parameters:
annotationClass
- the Class object corresponding to the annotation type- Returns:
- this element's annotation for the specified annotation type if present on this element, else null
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getAnnotations
public final Annotation[] getAnnotations()
Description copied from interface:java.lang.reflect.AnnotatedElement
Returns annotations that are present on this element. If there are no annotations present on this element, the return value is an array of length 0. The caller of this method is free to modify the returned array; it will have no effect on the arrays returned to other callers.- Specified by:
getAnnotations
in interfaceAnnotatedElement
- Returns:
- annotations present on this element
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getDeclaredAnnotations
public final Annotation[] getDeclaredAnnotations()
Description copied from interface:java.lang.reflect.AnnotatedElement
Returns annotations that are directly present on this element. This method ignores inherited annotations. If there are no annotations directly present on this element, the return value is an array of length 0. The caller of this method is free to modify the returned array; it will have no effect on the arrays returned to other callers.- Specified by:
getDeclaredAnnotations
in interfaceAnnotatedElement
- Returns:
- annotations directly present on this element
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getTypeParameters
public abstract TypeVariable<?>[] getTypeParameters()
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setAccessible
public final void setAccessible(boolean flag)
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trySetAccessible
public final boolean trySetAccessible()
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isAccessible
public final boolean isAccessible()
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getName
public final String getName()
Description copied from interface:java.lang.reflect.Member
Returns the simple name of the underlying member or constructor represented by this Member.
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getModifiers
public final int getModifiers()
Description copied from interface:java.lang.reflect.Member
Returns the Java language modifiers for the member or constructor represented by this Member, as an integer. The Modifier class should be used to decode the modifiers in the integer.- Specified by:
getModifiers
in interfaceMember
- Returns:
- the Java language modifiers for the underlying member
- See Also:
Modifier
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isSynthetic
public final boolean isSynthetic()
Description copied from interface:java.lang.reflect.Member
Returnstrue
if this member was introduced by the compiler; returnsfalse
otherwise.- Specified by:
isSynthetic
in interfaceMember
- Returns:
- true if and only if this member was introduced by the compiler.
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isPublic
public final boolean isPublic()
Returns true if the element is public.
-
isProtected
public final boolean isProtected()
Returns true if the element is protected.
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isPackagePrivate
public final boolean isPackagePrivate()
Returns true if the element is package-private.
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isPrivate
public final boolean isPrivate()
Returns true if the element is private.
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isStatic
public final boolean isStatic()
Returns true if the element is static.
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isFinal
public final boolean isFinal()
Returnstrue
if this method is final, perModifier.isFinal(getModifiers())
.Note that a method may still be effectively "final", or non-overridable when it has no
final
keyword. For example, it could be private, or it could be declared by a final class. To tell whether a method is overridable, useisOverridable()
.
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isAbstract
public final boolean isAbstract()
Returns true if the method is abstract.
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isNative
public final boolean isNative()
Returns true if the element is native.
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isSynchronized
public final boolean isSynchronized()
Returns true if the method is synchronized.
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equals
public boolean equals(@CheckForNull Object obj)
Description copied from class:java.lang.Object
Indicates whether some other object is "equal to" this one.The
equals
method implements an equivalence relation on non-null object references:- It is reflexive: for any non-null reference value
x
,x.equals(x)
should returntrue
. - It is symmetric: for any non-null reference values
x
andy
,x.equals(y)
should returntrue
if and only ify.equals(x)
returnstrue
. - It is transitive: for any non-null reference values
x
,y
, andz
, ifx.equals(y)
returnstrue
andy.equals(z)
returnstrue
, thenx.equals(z)
should returntrue
. - It is consistent: for any non-null reference values
x
andy
, multiple invocations ofx.equals(y)
consistently returntrue
or consistently returnfalse
, provided no information used inequals
comparisons on the objects is modified. - For any non-null reference value
x
,x.equals(null)
should returnfalse
.
The
equals
method for classObject
implements the most discriminating possible equivalence relation on objects; that is, for any non-null reference valuesx
andy
, this method returnstrue
if and only ifx
andy
refer to the same object (x == y
has the valuetrue
).Note that it is generally necessary to override the
hashCode
method whenever this method is overridden, so as to maintain the general contract for thehashCode
method, which states that equal objects must have equal hash codes.- Overrides:
equals
in classObject
- Parameters:
obj
- the reference object with which to compare.- Returns:
true
if this object is the same as the obj argument;false
otherwise.- See Also:
Object.hashCode()
,HashMap
- It is reflexive: for any non-null reference value
-
hashCode
public int hashCode()
Description copied from class:java.lang.Object
Returns a hash code value for the object. This method is supported for the benefit of hash tables such as those provided byHashMap
.The general contract of
hashCode
is:- Whenever it is invoked on the same object more than once during
an execution of a Java application, the
hashCode
method must consistently return the same integer, provided no information used inequals
comparisons on the object is modified. This integer need not remain consistent from one execution of an application to another execution of the same application. - If two objects are equal according to the
equals(Object)
method, then calling thehashCode
method on each of the two objects must produce the same integer result. - It is not required that if two objects are unequal
according to the
Object.equals(java.lang.Object)
method, then calling thehashCode
method on each of the two objects must produce distinct integer results. However, the programmer should be aware that producing distinct integer results for unequal objects may improve the performance of hash tables.
As much as is reasonably practical, the hashCode method defined by class
Object
does return distinct integers for distinct objects. (The hashCode may or may not be implemented as some function of an object's memory address at some point in time.)- Overrides:
hashCode
in classObject
- Returns:
- a hash code value for this object.
- See Also:
Object.equals(java.lang.Object)
,System.identityHashCode(java.lang.Object)
- Whenever it is invoked on the same object more than once during
an execution of a Java application, the
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toString
public String toString()
Description copied from class:java.lang.Object
Returns a string representation of the object. In general, thetoString
method returns a string that "textually represents" this object. The result should be a concise but informative representation that is easy for a person to read. It is recommended that all subclasses override this method.The
toString
method for classObject
returns a string consisting of the name of the class of which the object is an instance, the at-sign character `@
', and the unsigned hexadecimal representation of the hash code of the object. In other words, this method returns a string equal to the value of:getClass().getName() + '@' + Integer.toHexString(hashCode())
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isOverridable
public abstract boolean isOverridable()
Returnstrue
if this is an overridable method. Constructors, private, static or final methods, or methods declared by final classes are not overridable.
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isVarArgs
public abstract boolean isVarArgs()
Returnstrue
if this was declared to take a variable number of arguments.
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invoke
@CanIgnoreReturnValue @CheckForNull public final R invoke(@CheckForNull T receiver, @Nullable Object... args) throws InvocationTargetException, IllegalAccessException
Invokes withreceiver
as 'this' andargs
passed to the underlying method and returns the return value; or calls the underlying constructor withargs
and returns the constructed instance.- Throws:
IllegalAccessException
- if thisConstructor
object enforces Java language access control and the underlying method or constructor is inaccessible.IllegalArgumentException
- 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 or constructor throws an exception.
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getReturnType
public final TypeToken<? extends R> getReturnType()
Returns the return type of thisInvokable
.
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getParameters
public final ImmutableList<Parameter> getParameters()
Returns all declared parameters of thisInvokable
. Note that if this is a constructor of a non-static inner class, unlikeConstructor.getParameterTypes()
, the hiddenthis
parameter of the enclosing class is excluded from the returned parameters.
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getExceptionTypes
public final ImmutableList<TypeToken<? extends Throwable>> getExceptionTypes()
Returns all declared exception types of thisInvokable
.
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returning
public final <R1 extends R> Invokable<T,R1> returning(Class<R1> returnType)
Explicitly specifies the return type of thisInvokable
. For example:Method factoryMethod = Person.class.getMethod("create"); Invokable<?, Person> factory = Invokable.of(getNameMethod).returning(Person.class);
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returning
public final <R1 extends R> Invokable<T,R1> returning(TypeToken<R1> returnType)
Explicitly specifies the return type of thisInvokable
.
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getDeclaringClass
public final Class<? super T> getDeclaringClass()
Description copied from interface:java.lang.reflect.Member
Returns the Class object representing the class or interface that declares the member or constructor represented by this Member.- Specified by:
getDeclaringClass
in interfaceMember
- Returns:
- an object representing the declaring class of the underlying member
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getOwnerType
public TypeToken<T> getOwnerType()
Returns the type ofT
.
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getAnnotatedReturnType
public abstract AnnotatedType getAnnotatedReturnType()
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