Can I guarantee typing on an argument's class AND interface?

Question

I am using the GWT library. There is a base class called Widget that all Widgets inherit from. Some Widgets implement certain interfaces (for example HasText), others do not. Sometimes I wish to guarantee that something being passed as an argument to a function is of a certain class AND implements a certain interface.

For example, I wish to have a function that takes a argument X, where X is of the class type Widget AND of the interface type HasText. I wish to have this behavior because only Widgets can be added to Layout containers, and HasText specifies the complete set of behaviors that I actually need from said Widget.

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In pseudocode form, it might be:

public void fx(I_AM_A_Widget_AND_IMPLEMENT_INTERFACE_HasText x){
    //do stuff with x, which is guaranteed to be a Widget AND implement HasText
}

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Is this in any way possible in Java? If there are multiple ways to do so, is there a preferred/better way?

Answer 1

You might be able to use a generic method here:

public <T extends Widget & HasText> void fx(T x)

The compiler will infer the type of T automatically, so no extra syntax when calling the method.