Class 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:
    java.lang.reflect.AnnotatedElement, java.lang.reflect.Member

    @Beta
    public abstract class Invokable<T,​R>
    extends java.lang.Object
    implements java.lang.reflect.AnnotatedElement, java.lang.reflect.Member
    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());
     

    Note: earlier versions of this class inherited from AccessibleObject and GenericDeclaration. 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 or GenericDeclaration since 31.0)
    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 Description
      boolean equals​(java.lang.Object obj)  
      static <T> Invokable<T,​T> from​(java.lang.reflect.Constructor<T> constructor)
      Returns Invokable of constructor.
      static Invokable<?,​java.lang.Object> from​(java.lang.reflect.Method method)
      Returns Invokable of method.
      abstract java.lang.reflect.AnnotatedType getAnnotatedReturnType()  
      <A extends java.lang.annotation.Annotation>
      A
      getAnnotation​(java.lang.Class<A> annotationClass)  
      java.lang.annotation.Annotation[] getAnnotations()  
      java.lang.annotation.Annotation[] getDeclaredAnnotations()  
      java.lang.Class<? super T> getDeclaringClass()  
      ImmutableList<TypeToken<? extends java.lang.Throwable>> getExceptionTypes()
      Returns all declared exception types of this Invokable.
      int getModifiers()  
      java.lang.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.
      abstract java.lang.reflect.TypeVariable<?>[] getTypeParameters()
      See GenericDeclaration.getTypeParameters().
      int hashCode()  
      R invoke​(T receiver, @Nullable java.lang.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()
      See AccessibleObject.isAccessible().
      boolean isAnnotationPresent​(java.lang.Class<? extends java.lang.annotation.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​(TypeToken<R1> returnType)
      Explicitly specifies the return type of this Invokable.
      <R1 extends R>
      Invokable<T,​R1>
      returning​(java.lang.Class<R1> returnType)
      Explicitly specifies the return type of this Invokable.
      void setAccessible​(boolean flag)
      See AccessibleObject.setAccessible(boolean).
      java.lang.String toString()  
      boolean trySetAccessible()
      See AccessibleObject.trySetAccessible().
      • Methods inherited from class java.lang.Object

        clone, finalize, getClass, notify, notifyAll, wait, wait, wait
      • Methods inherited from interface java.lang.reflect.AnnotatedElement

        getAnnotationsByType, getDeclaredAnnotation, getDeclaredAnnotationsByType
    • Method Detail

      • from

        public static Invokable<?,​java.lang.Object> from​(java.lang.reflect.Method method)
        Returns Invokable of method.
      • from

        public static <T> Invokable<T,​T> from​(java.lang.reflect.Constructor<T> constructor)
        Returns Invokable of constructor.
      • isAnnotationPresent

        public final boolean isAnnotationPresent​(java.lang.Class<? extends java.lang.annotation.Annotation> annotationClass)
        Specified by:
        isAnnotationPresent in interface java.lang.reflect.AnnotatedElement
      • getAnnotation

        @CheckForNull
        public final <A extends java.lang.annotation.Annotation> A getAnnotation​(java.lang.Class<A> annotationClass)
        Specified by:
        getAnnotation in interface java.lang.reflect.AnnotatedElement
      • getAnnotations

        public final java.lang.annotation.Annotation[] getAnnotations()
        Specified by:
        getAnnotations in interface java.lang.reflect.AnnotatedElement
      • getDeclaredAnnotations

        public final java.lang.annotation.Annotation[] getDeclaredAnnotations()
        Specified by:
        getDeclaredAnnotations in interface java.lang.reflect.AnnotatedElement
      • getTypeParameters

        public abstract java.lang.reflect.TypeVariable<?>[] getTypeParameters()
        See GenericDeclaration.getTypeParameters().
      • setAccessible

        public final void setAccessible​(boolean flag)
        See AccessibleObject.setAccessible(boolean).
      • trySetAccessible

        public final boolean trySetAccessible()
        See AccessibleObject.trySetAccessible().
      • isAccessible

        public final boolean isAccessible()
        See AccessibleObject.isAccessible().
      • getName

        public final java.lang.String getName()
        Specified by:
        getName in interface java.lang.reflect.Member
      • getModifiers

        public final int getModifiers()
        Specified by:
        getModifiers in interface java.lang.reflect.Member
      • isSynthetic

        public final boolean isSynthetic()
        Specified by:
        isSynthetic in interface java.lang.reflect.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​(@CheckForNull
                              java.lang.Object obj)
        Overrides:
        equals in class java.lang.Object
      • hashCode

        public int hashCode()
        Overrides:
        hashCode in class java.lang.Object
      • toString

        public java.lang.String toString()
        Overrides:
        toString in class java.lang.Object
      • 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

        @CanIgnoreReturnValue
        @CheckForNull
        public final R invoke​(@CheckForNull
                              T receiver,
                              @Nullable java.lang.Object... args)
                       throws java.lang.reflect.InvocationTargetException,
                              java.lang.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:
        java.lang.IllegalAccessException - if this Constructor object enforces Java language access control and the underlying method or constructor is inaccessible.
        java.lang.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.
        java.lang.reflect.InvocationTargetException - if the underlying method or constructor throws an exception.
      • getParameters

        public final ImmutableList<ParametergetParameters()
        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.
      • returning

        public final <R1 extends RInvokable<T,​R1> returning​(java.lang.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 RInvokable<T,​R1> returning​(TypeToken<R1> returnType)
        Explicitly specifies the return type of this Invokable.
      • getDeclaringClass

        public final java.lang.Class<? super TgetDeclaringClass()
        Specified by:
        getDeclaringClass in interface java.lang.reflect.Member