泛型：确保参数的类型相同

发布于 2025-01-06 12:19:25 字数 386 浏览 1 评论 0原文

我有以下方法：

protected <S> void setValue(final S oldValue, final S newValue) {
    // Do something
}

我想确保两个参数的类型相同。如果当您尝试传递两种不同类型的参数时出现编译器错误，那就太酷了。

上面的方式显然不是正确的方式。我可以放入一个String 和一个Integer，因为它们都是从Object 扩展的。

我的愿望可能实现吗？或者是确保两个参数具有相同类型的唯一方法，以便在方法内检查它并抛出 IllegalArgumentException？

原文

I've got the following method:

protected <S> void setValue(final S oldValue, final S newValue) {
    // Do something
}

I want to make sure, that both parameters are of the same type. It would be cool, if there'd be a compiler error when you try to pass parameters of two different types.

The above way is clearly not the correct one. I can put into a String and an Integer, since the both extend from Object.

Is my want even possible? Or is the only way to make sure both parameters are of the same type to check it inside the method and throw an IllegalArgumentException?

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眼眸印温柔 2025-01-13 12:19:25

如果您认为 S 是正确的类型，则可以这样做：

protected <S, T extends S> void setValue(final S oldValue, final T newValue) {
    // Do something
}

您可以也不能输入这些：

// Works
setValue("something", "something");
setValue(new Object(), new String());

// Doesn't work
setValue(new String(), new Object());

或

您可以这样做：

protected <S> void setValue(final S oldValue, final S newValue, final Class<S> clazz) {
    // Do something
}

并像这样使用它

setValue("something", "something", String.class);

或

protected <S> void setValue(final S oldValue, final S newValue) {
    if(!oldValue.getClass().equals(newValue.getClass())) {
        //throw something
    }
}

You can do that if you consider that S is the correct type :

protected <S, T extends S> void setValue(final S oldValue, final T newValue) {
    // Do something
}

You can and can't input these :

// Works
setValue("something", "something");
setValue(new Object(), new String());

// Doesn't work
setValue(new String(), new Object());

You can do :

protected <S> void setValue(final S oldValue, final S newValue, final Class<S> clazz) {
    // Do something
}

and use it like that

setValue("something", "something", String.class);

protected <S> void setValue(final S oldValue, final S newValue) {
    if(!oldValue.getClass().equals(newValue.getClass())) {
        //throw something
    }
}

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