通用或代替和＆lt;吨延伸号| CharSequence的＆GT; [英] Generic OR instead of AND <T extends Number | CharSequence>

问题描述

是否有可能一般参数的方法接受无论是ClassA的或InterfaceB？

不编译由于|伪code

 公开＆LT;吨延伸号| CharSequence的＆GT;无效orDoer（T someData）{// ...}
 

即。而不是写多个方法签名，我想这个方法接受一个数字或CharSequence中作为参数

如果以数字或CharSequence参数传递

  orDoer（新的整数（6））;
INT somePrimitive = 4;
orDoer（somePrimitive）;
orDoer（字符的字符串）;
 

解决方案

如果您真的要做到这一点，你需要来包装自己的自定义类中youur接受类。在您的例子的情况下，大概是这样的：

 公共类OrDoerElement {
    私人最终数量numberValue;
    私人最终的CharSequence charSequenceValue;

    私人OrDoerElement（数数，CharSequence中的CharSequence）{
        this.numberValue =号;
        this.charSequenceValue = CharSequence的;
    }

    公共静态OrDoerElement fromCharSequence（CharSequence的值）{
        返回新OrDoerElement（NULL，值）;
    }

    公共静态OrDoerElement fromNumber（数字值）{
        返回新OrDoerElement（值null）;
    }
}
 

和您的 orDoer 方法就变成了：

 公共无效orDoer（OrDoerElement someData）{....}
 

然后就可以建立这些之一，并使用你的方法请使用：

  orDoer（OrDoerElement.fromCharSequence（字符的字符串））;
orDoer（OrDoerElement.fromNumber（新的整数（6）））;
 

不过说实话，这听起来有点太复杂，太多的工作只是为了能够调用不同的参数类型的方法。您使用的两种方法，并为共同的逻辑第三种方法肯定不能达到同样的？

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

Does Not Compile Due to | Pseudocode

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

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

Should Pass with a Number OR CharSequence argument

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

解决方案

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);
    }
}

And your orDoer method becomes:

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

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)));

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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