Declare parameter subtypes in Java interfaces and use subtypes in Java implementation methods

I want to declare a method in the interface, where the parameters of the method defined in the implementation class can be subtypes of a specific Java class, for example:

interface Processor{
      processRequest( Request r);
}

public class SpecialRequest extends Request{...}

public class SpecialProcessor implements Processor{

      processRequest(SpecialRequest r){...}
}

But I encountered an error in specialprocessor because it did not implement the processor interface correctly What can I change in the processor interface to allow definitions in specialprocessor to work?

Solution

You can enter the processor:

public interface Processor<R extends Request> {
    void processRequest(R r);
}


public class SpecialProcessor implements Processor<SpecialRequest> {
    public void processRequest(SpecialRequest r) {
       ...
    }
}