From: Bauke Scholtz <balusc_at_gmail.com>
Date: Sat, 23 Jul 2016 23:42:50 +0200

Hi,

Check all implementing classes of FacesWrapper:
https://docs.oracle.com/javaee/7/api/javax/faces/FacesWrapper.html When
extending such a FacesWrapper class like ResourceWrapper you always end up
with below minimally required boilerplate:


public class MyResource extends ResourceWrapper {
    private Resource wrapped;

    public MyResource(Resource wrapped) {
        this.wrapped = wrapped;
    }

    @Override
    public Resource getWrapped() {
        return wrapped;
    }
}


Compare with a.o.
http://docs.oracle.com/javaee/7/api/javax/servlet/http/HttpServletRequestWrapper.html
It has an explicit constructor taking wrapped instance and already a
default getWrapped() implementation returning exactly that.


public class MyRequest extends HttpServletRequestWrapper {
    public MyRequest(HttpServletRequest wrapped) {
        super(wrapped);
    }
}


You just have to push wrapped to super() and there's already a default
implementation for getWrapped(). This also forces developers to use
getWrapped() instead of the local variable. Because, when developers use
the local variable, the decorator chain may break when the wrapper instance
is in turn wrapped by another wrapper instance (as can be seen in a.o.
ResponseWriterWrapper when using MyFaces as its PartialResponseWriter
extends from it but internally doesn't correctly use getWrapped()).

I propose improving all FacesWrapper classes to add such a constructor
(along with the default one) so that boilerplate can be reduced and
robustness can be improved.

Thoughts?

Cheers, B