方法参数extends class implements interface [英] Method argument extends class implements interface

问题描述

我有以下类和接口：

public class BasicObject{...}
public interface CodeObject{...}

我想创建一个方法，其中参数必须是BasicObject类型并实现CodeObject。我尝试了以下代码，但它不保证clazz是一个实现CodeObject的类。

I want to create a method in which the argument needs to be of type BasicObject and implements CodeObject. I tried the following code but it doesn't guarantee clazz to be a class that implements CodeObject.

myMethod(Class<? extends BasicObject> clazz){...}

我想做这样的事情，但它没有编译：

I want to do something like this but it doesn't compile:

myMethod(Class<? extends BasicObject implements CodeObject> clazz){...}

推荐答案

您的模式类必须扩展 BasicObject 并扩展/实现 CodeObject （实际上是一个接口）。您可以使用方法签名的通配符定义中声明的多个类来执行此操作，如下所示：

Your pattern class has to extend BasicObject and extend/implement CodeObject (which is actually an interface). You can do it with multiple classes declared in the wildcard definition of the method signature, like this:

public <T extends BasicObject & CodeObject> void myMethod(Class<T> clazz)

请注意，如果你这样做，它将无效这些方式：

Note that it won't work if you do it any of these ways:

• public< T extends BasicObject，CodeObject> void myMethod（Class< T> clazz）

这是技术上有效的语法，但 CodeObject 未使用;该方法将接受任何扩展 BasicObject 的类，无论它们是否扩展/实现 CodeObject 。

This is technically valid syntax, but CodeObject is unused; the method will accept any classes that extends BasicObject, no matter whether they extend/implement CodeObject.

public void myMethod（Class<？extends BasicObject& CodeObject> clazz）

public void myMethod（Class<？extends BasicObject，CodeObject> clazz）

根据Java，这些只是错误的语法。

These are just wrong syntax according to Java.

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