通用 OR 而不是 AND <T extends Number |字符序列> [英] Generic OR instead of AND <T extends Number | CharSequence>

问题描述

是否可以对接受 ClassA 或 InterfaceB 的方法进行一般参数化?

Is it possible to generically parameterize a method accepting EITHER ClassA OR InterfaceB ?

不编译由于 |伪代码

public <T extends Number | CharSequence> void orDoer(T someData){ // ... }

即而不是编写多个方法签名，我希望这个方法接受一个 Number 或 CharSequence 作为参数

i.e. instead of writing multiple method signatures, I would like this one method to accept either a Number or CharSequence as an argument

应该传递一个 Number OR CharSequence 参数

orDoer(new Integer(6));
int somePrimitive = 4;
orDoer(somePrimitive);
orDoer("a string of chars");

推荐答案

如果您真的想要这样做，您需要将您接受的类包装在您自己的自定义类中.在您的示例中，可能类似于:

If you really want to do that, you'll need to wrap youur accepted classes inside a custom class of your own. In your example case, probably something like:

public class OrDoerElement {
    private final Number numberValue;
    private final CharSequence charSequenceValue;

    private OrDoerElement(Number number, CharSequence charSequence) {
        this.numberValue = number;
        this.charSequenceValue = charSequence;
    }

    public static OrDoerElement fromCharSequence(CharSequence value) {
        return new OrDoerElement(null, value);
    }

    public static OrDoerElement fromNumber(Number value) {
        return new OrDoerElement(value, null);
    }
}

你的 orDoer 方法变成:

public void orDoer(OrDoerElement someData) { .... }

然后您可以构建其中一个并使用以下任一方法在您的方法中使用:

Then you can build one of those and use in your method using either:

orDoer(OrDoerElement.fromCharSequence("a string of chars"));
orDoer(OrDoerElement.fromNumber(new Integer(6)));

但老实说，仅仅为了能够调用具有不同参数类型的方法，这听起来有点太复杂和太多的工作.你确定你不能用两种方法来达到同样的效果，而用第三种方法来实现通用逻辑吗?

But honestly, that sounds a bit too complex and too much work just to be able to call a method with different parameter types. Are you sure you can't achieve the same using two methods, and a third method for the common logic?

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