Scala:在运行时获取混合接口 [英] Scala : get mixin interfaces at runtime

问题描述

我需要在运行时从给定的类中获取所有接口(所有接口都加载到ClassLoader中).

I need to get all the interfaces at runtime from a given Class (all loaded in a ClassLoader).

例如，如果以这种方式声明了一个类:

For instance, if a class has been declared this way :

trait B
trait C
trait D    
class A extends B with C with D

我想在运行时获取此信息: A取决于B，C和D . java getInterfaces()(或clapper库中的interfaces())方法仅给出第一个依赖项，即: A依赖于B .

I want to get this information at runtime : A depends on B and C and D. The java getInterfaces() (or the interfaces() from the clapper library) methods gives only the first dependency, namely: A depends on B.

有没有办法实现这一目标?

Is there a way to achieve that ?

我通过反思来猜测，但是我不知道如何?

I guess by reflection but I don't know how ?

推荐答案

这个问题给出了答案:

import scala.reflect.runtime.universe._

trait B
trait C
class A extends B with C

val tpe = typeOf[A]
tpe.baseClasses foreach {s => println(s.fullName)}
  // A, C, B, java.lang.Object, scala.Any   

它可以在REPL中使用，但是当我将代码放入Scala脚本文件并执行后，它不再存在:

It works in the REPL, but when I put the code into a Scala script file and executed it, it didn't any longer:

typeOf[A]
  // Compiler error: No TypeTag available for this.A

使用weakTypeTag也不起作用

weakTypeTag[A]
  // Runtime error: scala.reflect.internal.FatalError:
  // ThisType(free type $anon) for sym which is not a class

Scala 2.10.0、2.10.1和2.11.0-M2的行为相同.

I got the same behaviour with Scala 2.10.0, 2.10.1 and 2.11.0-M2.

这篇关于Scala:在运行时获取混合接口的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！