Invokable (Guava: Google Core Libraries for Java 20.0 API)

java.lang.Object
- java.lang.reflect.AccessibleObject
- - com.google.common.reflect.Invokable<T,R>

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, GenericDeclaration, Member
```
@Beta
public abstract class Invokable<T,R>
extends AccessibleObject
implements GenericDeclaration
```
Wrapper around either a Method or a Constructor. Convenience API is provided to make common reflective operation easier to deal with, such as isPublic(), getParameters() etc.
In addition to convenience methods, TypeToken.method(java.lang.reflect.Method) and TypeToken.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());
```
Since:

14.0

Author:

Ben Yu

Field Summary
- Fields inherited from interface java.lang.reflect.Member
  DECLARED, PUBLIC

Method Summary

All Methods Static Methods Instance Methods Abstract Methods Concrete Methods
Modifier and Type	Method and Description
`boolean`	`equals(Object obj)`
`static <T> Invokable<T,T>`	`from(Constructor<T> constructor)` Returns `Invokable` of `constructor`.
`static Invokable<?,Object>`	`from(Method method)` Returns `Invokable` of `method`.
`<A extends Annotation> A`	`getAnnotation(Class<A> annotationClass)`
`Annotation[]`	`getAnnotations()`
`Annotation[]`	`getDeclaredAnnotations()`
`Class<? super T>`	`getDeclaringClass()`
`ImmutableList<TypeToken<? extends Throwable>>`	`getExceptionTypes()` Returns all declared exception types of this `Invokable`.
`int`	`getModifiers()`
`String`	`getName()`
`TypeToken<T>`	`getOwnerType()` Returns the type of `T`.
`ImmutableList<Parameter>`	`getParameters()` Returns all declared parameters of this `Invokable`.
`TypeToken<? extends R>`	`getReturnType()` Returns the return type of this `Invokable`.
`int`	`hashCode()`
`R`	`invoke(T receiver, Object... args)` Invokes with `receiver` as 'this' and `args` passed to the underlying method and returns the return value; or calls the underlying constructor with `args` and returns the constructed instance.
`boolean`	`isAbstract()` Returns true if the method is abstract.
`boolean`	`isAccessible()`
`boolean`	`isAnnotationPresent(Class<? extends Annotation> annotationClass)`
`boolean`	`isFinal()` Returns `true` if this method is final, per `Modifier.isFinal(getModifiers())`.
`boolean`	`isNative()` Returns true if the element is native.
`abstract boolean`	`isOverridable()` Returns `true` 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()`
`abstract boolean`	`isVarArgs()` Returns `true` if this was declared to take a variable number of arguments.
`<R1 extends R> Invokable<T,R1>`	`returning(Class<R1> returnType)` Explicitly specifies the return type of this `Invokable`.
`<R1 extends R> Invokable<T,R1>`	`returning(TypeToken<R1> returnType)` Explicitly specifies the return type of this `Invokable`.
`void`	`setAccessible(boolean flag)`
`String`	`toString()`

Methods inherited from class java.lang.reflect.AccessibleObject
getAnnotationsByType, getDeclaredAnnotation, getDeclaredAnnotationsByType, setAccessible

Methods inherited from class java.lang.Object
clone, finalize, getClass, notify, notifyAll, wait, wait, wait

Methods inherited from interface java.lang.reflect.GenericDeclaration
getTypeParameters

Methods inherited from interface java.lang.reflect.AnnotatedElement
getAnnotation, getAnnotations, getAnnotationsByType, getDeclaredAnnotation, getDeclaredAnnotations, getDeclaredAnnotationsByType, isAnnotationPresent

- Method Detail
  - from
```
public static Invokable<?,Object> from(Method method)
```
    Returns Invokable of method.
  - from
```
public static <T> Invokable<T,T> from(Constructor<T> constructor)
```
    Returns Invokable of constructor.
  - isOverridable
```
public abstract boolean isOverridable()
```
    Returns true if this is an overridable method. Constructors, private, static or final methods, or methods declared by final classes are not overridable.
  - isVarArgs
```
public abstract boolean isVarArgs()
```
    Returns true if this was declared to take a variable number of arguments.
  - invoke
```
public final R invoke(@Nullable
                      T receiver,
                      Object... args)
               throws InvocationTargetException,
                      IllegalAccessException
```
    Invokes with receiver as 'this' and args passed to the underlying method and returns the return value; or calls the underlying constructor with args and returns the constructed instance.
    
    Throws:
    
    IllegalAccessException - if this Constructor 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.
  - getReturnType
```
public final TypeToken<? extends R> getReturnType()
```
    Returns the return type of this Invokable.
  - getParameters
```
public final ImmutableList<Parameter> getParameters()
```
    Returns all declared parameters of this Invokable. Note that if this is a constructor of a non-static inner class, unlike Constructor.getParameterTypes(), the hidden this parameter of the enclosing class is excluded from the returned parameters.
  - getExceptionTypes
```
public final ImmutableList<TypeToken<? extends Throwable>> getExceptionTypes()
```
    Returns all declared exception types of this Invokable.
  - returning
```
public final <R1 extends R> Invokable<T,R1> returning(Class<R1> returnType)
```
    Explicitly specifies the return type of this Invokable. For example:
```
   
   Method factoryMethod = Person.class.getMethod("create");
   Invokable<?, Person> factory = Invokable.of(getNameMethod).returning(Person.class);
```
  - returning
```
public final <R1 extends R> Invokable<T,R1> returning(TypeToken<R1> returnType)
```
    Explicitly specifies the return type of this Invokable.
  - getDeclaringClass
```
public final Class<? super T> getDeclaringClass()
```
    Specified by:
    
    getDeclaringClass in interface Member
  - getOwnerType
```
public TypeToken<T> getOwnerType()
```
    Returns the type of T.
  - isAnnotationPresent
```
public final boolean isAnnotationPresent(Class<? extends Annotation> annotationClass)
```
    Specified by:
    
    isAnnotationPresent in interface AnnotatedElement
    
    Overrides:
    
    isAnnotationPresent in class AccessibleObject
  - getAnnotation
```
public final <A extends Annotation> A getAnnotation(Class<A> annotationClass)
```
    Specified by:
    
    getAnnotation in interface AnnotatedElement
    
    Overrides:
    
    getAnnotation in class AccessibleObject
  - getAnnotations
```
public final Annotation[] getAnnotations()
```
    Specified by:
    
    getAnnotations in interface AnnotatedElement
    
    Overrides:
    
    getAnnotations in class AccessibleObject
  - getDeclaredAnnotations
```
public final Annotation[] getDeclaredAnnotations()
```
    Specified by:
    
    getDeclaredAnnotations in interface AnnotatedElement
    
    Overrides:
    
    getDeclaredAnnotations in class AccessibleObject
  - setAccessible
```
public final void setAccessible(boolean flag)
                         throws SecurityException
```
    Overrides:
    
    setAccessible in class AccessibleObject
    
    Throws:
    
    SecurityException
  - isAccessible
```
public final boolean isAccessible()
```
    Overrides:
    
    isAccessible in class AccessibleObject
  - getName
```
public final String getName()
```
    Specified by:
    
    getName in interface Member
  - getModifiers
```
public final int getModifiers()
```
    Specified by:
    
    getModifiers in interface Member
  - isSynthetic
```
public final boolean isSynthetic()
```
    Specified by:
    
    isSynthetic in interface Member
  - isPublic
```
public final boolean isPublic()
```
    Returns true if the element is public.
  - isProtected
```
public final boolean isProtected()
```
    Returns true if the element is protected.
  - isPackagePrivate
```
public final boolean isPackagePrivate()
```
    Returns true if the element is package-private.
  - isPrivate
```
public final boolean isPrivate()
```
    Returns true if the element is private.
  - isStatic
```
public final boolean isStatic()
```
    Returns true if the element is static.
  - isFinal
```
public final boolean isFinal()
```
    Returns true if this method is final, per Modifier.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, use isOverridable().
  - isAbstract
```
public final boolean isAbstract()
```
    Returns true if the method is abstract.
  - isNative
```
public final boolean isNative()
```
    Returns true if the element is native.
  - isSynchronized
```
public final boolean isSynchronized()
```
    Returns true if the method is synchronized.
  - equals
```
public boolean equals(@Nullable
                      Object obj)
```
    Overrides:
    
    equals in class Object
  - hashCode
```
public int hashCode()
```
    Overrides:
    
    hashCode in class Object
  - toString
```
public String toString()
```
    Overrides:
    
    toString in class Object

Class Invokable<T,R>

Field Summary

Fields inherited from interface java.lang.reflect.Member

Method Summary

Methods inherited from class java.lang.reflect.AccessibleObject

Methods inherited from class java.lang.Object

Methods inherited from interface java.lang.reflect.GenericDeclaration

Methods inherited from interface java.lang.reflect.AnnotatedElement

Method Detail

from

from

isOverridable

isVarArgs

invoke

getReturnType

getParameters

getExceptionTypes

returning

returning

getDeclaringClass

getOwnerType

isAnnotationPresent

getAnnotation

getAnnotations

getDeclaredAnnotations

setAccessible

isAccessible

getName

getModifiers

isSynthetic

isPublic

isProtected

isPackagePrivate

isPrivate

isStatic

isFinal

isAbstract

isNative

isSynchronized

equals

hashCode

toString