Java Generics as parameters

Question

So I have a bunch of methods that essentially make the same call the only difference is class names of generics. Example:

Current:

public void methodA(ARequest request, ADelegate delegate)
{
     JsonClient<ARequest, AResponse> client = new JsonClient<ARequest, AResponse>(request.ServiceServerUrl, request, new AResponse());
     client.sendRequest(delegate);
}

public void methodB(BRequest request, BDelegate delegate)
{
         JsonClient<BRequest, BResponse> client = new JsonClient<BRequest, BResponse>(request.ServiceServerUrl, request, new BResponse());
         client.sendRequest(delegate);
}

What I want to do is:

private void serviceCall<R extends RequestBase, S extends ResponseBase>(ADelegate delegate)
{
    JsonClient<R, S> client = new JsonClient<R, S>(request.ServiceServerUrl, request, new AResponse());
    client.sendRequest(delegate);
}

public void methodA(ARequest request, ADelegate delegate)
{
    serviceCall<ARequest, AResponse>(delegate);
}

public void methodB(BRequest request, BDelegate delegate)
{
    serviceCall<BRequest, BResponse>(delegate);
}

I think this is possible in C# but I just want to know how to properly do this in Java.

Edit: For clarity.

Answer 1

You should be able to write the following:

private <R extends RequestBase, S extends ResponseBase> void serviceCall(
        R request,
        S response,
        ADelegate delegate
) {
    JsonClient<R, S> client = new JsonClient<R, S>(request.ServiceServerUrl, request, response);
    client.sendRequest(delegate);
}

Note that the caller must instantiate and pass in response , since something like new S() isn't possible in Java:

public void method(ARequest request, ADelegate delegate) {
    serviceCall(request, new AResponse(), delegate);
}

Something like

MyClass.<ARequest, AResponse>serviceCall(request, new AResponse(), delegate)

isn't necessary here because the compiler infers the type arguments for you.

Answer 2

Do you mean?

public <T extends RequestBase, E extends ResponseBase> void method(T request, E delegate)
{
     JsonClient<T, E> client = new JsonClient<T, E>(request.ServiceServerUrl, request, new AResponse());
     client.sendRequest(delegate);
}

and invoke it like ClassName.<ARequest, AResponse>method(request, response) .