protected TypeMirror interfaceGenericTypeFor(TypeElement element, Class interfaceType) {
        return interfaceGenericTypeFor(element, interfaceType.getName());
    }
protected TypeMirror interfaceGenericTypeFor ( TypeElement element , Class interfaceType ) { return interfaceGenericTypeFor ( element , interfaceType . getName ( ) ) ; }
Finds the generic type for the given interface for the given class element.
<p>
For example, for <code>class AProvider implements Provider</code>
element = AProvider
interfaceType = interface javax.inject.Provider.class
return A

@param element       The class element
@param interfaceType The interface
@return The generic type or null