Java Generics Wildcarding，用于具有多个类类型的单个param

Question

I have a method. It accepts a param, it can either be an object of the Provider or String class. Now if I tell that method to accept Object then I can pass it Provider or String object, but I want to make it type safe using generics and pass only either Provider or String . How do I do that, is it possible?
I want to achieve something like this:

public <T can be String or Provider> void myMethod(T value)

I had a look at this question , but it would not work in my case because none of Provider or String is an interface.

Answer 1

You should not (and can not) use generics for this. Instead simply provide two overloaded method:

public void myMethod(String value);
// and
public void myMethod(Provider value);

Since both need to have some different handling anyway it's actually simpler this way.

Answer 2

Not, that's not possible. How about simply having two overloaded methods instead?

public void myMethod(String value)
public void myMethod(Provider value)

Answer 3

Why exactly "Provider" or "String"? What do they have in common that makes your method work for both of them? For instance, are both Comparable ? Then you should use Comparable in there. If they do not share something in common, maybe there is a reason that you cannot do what you are trying to do. In that case, just use overloading, as others suggested.