Creating two generic parameters in an interface

Question

I am trying to create a generic interface for my classes that will satisfy them all. I have created base classes to link them all together but the interface I'm trying to create isn't working like I'd expect it to and I cant find the right words to type into the search to find them.

The interface so far is:

public <T extends SDOBase> T entityToSDO(<? extends BaseEntity> entity, T sdo) throws Exception;

How do I make entity a second generic type?

Answer 1

尝试以这种方式声明您的方法：

public <T extends SDOBase, E extends BaseEntity> T entityToSDO(E entity, T sdo) throws Exception;

Answer 2

I think you want something more along the lines of:

public interface MyInterface<T extends SDOBase>
{
    public T entityToSDO(<? extends BaseEntity> entity, T sdo) throws Exception;
}

Answer 3

You just need

public <T extends SDOBase> T entityToSDO(BaseEntity entity, T sdo) throws Exception;

Anything that is an instance of a subtype of BaseEntity automatically is an instance of BaseEntity.