如何比较类和接口？

Question

任何人都可以解释我如何比较自己的KClasse-s和接口吗？我知道如何检查类或接口都是平等的，但我不明白如何检查类是B级的超等

interface IB {} 
interface IC : IB {} 

open class A {} 
open class B : A() {} 
open class C : B(), IC {} 

fun main(args: Array<String>) { 
    if (B::class == B::class) { println("B class is equal to B class") } 
    if (IB::class == IB::class) { println("IB interface is equal to IB interface") } 

    if (A::class ??? B::class) { println("A class is parent of B class") } 
    if (A::class ??? C::class) { println("A class is superclass of C class") } 

    if (C::class ??? IC) { println("C class is implement IC interface") } 
    if (IC ??? IB) { println("IC interface is implement IB interface") } 
} 

Answer 1

科特林反射没有一个API，用于检索有关信息KClass层次，所以唯一的办法，以检查是否一个KClass是超或其他KClass子类是比较对应的Java类：

interface IB {} 
interface IC : IB {} 

open class A {} 
open class B : A() {} 
open class C : B(), IC {} 

fun main(args: Array<String>) { 
    if (B::class == B::class) { println("B class is equal to B class") } 
    if (IB::class == IB::class) { println("IB interface is equal to IB interface") } 

    if (A::class.java.isAssignableFrom(B::class.java)) { println("A class is parent of B class") } 
    if (A::class.java.isAssignableFrom(C::class.java)) { println("A class is superclass of C class") } 

    if (IC::class.java.isAssignableFrom(C::class.java)) { println("C class is implement IC interface") } 
    if (IB::class.java.isAssignableFrom(IC::class.java)) { println("IC interface is implement IB interface") } 
} 

UPDATE： 您也可以定义两个扩展功能，将麦Ë这种检查更好一点的：

inline fun <reified L : Any, reified R : Any> isSubClassOf(): Boolean { 
    return R::class.java.isAssignableFrom(L::class.java) 
} 

inline fun <reified L : Any, reified R : Any> isSuperClassOf(): Boolean { 
    return L::class.java.isAssignableFrom(R::class.java) 
} 

fun main(args: Array<String>) { 
    if (isSubClassOf<B, B>()) { println("B class is equal to B class") } 
    if (isSubClassOf<IB, IB>()) { println("IB interface is equal to IB interface") } 

    if (isSuperClassOf<A, B>()) { println("A class is parent of B class") } 
    if (isSuperClassOf<A, C>()) { println("A class is superclass of C class") } 

    if (isSubClassOf<C, IC>()) { println("C class is implement IC interface") } 
    if (isSubClassOf<IC, IB>()) { println("IC interface is implement IB interface") } 
}