The latest fluent-api Jaxb2 plugin now supports generating fluent api
methods with covariant return types.
https://jaxb2-commons.dev.java.net/fluent-api/
Let me know if any problem.
Enjoy,
Hanson
On 10/12/06, Kenny MacLeod <kennym_at_kizoom.com> wrote:
>
> It's jaxb-generated. A covariant return type would work just as well,
> although it would mean more auto-gen code being produced, with every
> subclass having to generate its own overriding withXYZ() method for each
> inherited property. Might get a bit cumbersome for deep inheritance
> structures.
>
> Hanson Char wrote:
> > Hi Kenny,
> >
> > Is Y a Jaxb generated pojo ? Or a hand coded one ?
> >
> > How about the alternative of using method overriding with covariant
> > return type in Y ? Example:
> >
> > class Y extends X {
> > public Y withA(String a) {
> > setA(a);
> > return this;
> > }
> > }
> >
> > Hanson
> >
> > On 10/12/06, Kenny MacLeod <kenny.macleod_at_kizoom.com> wrote:
> >>
> >>
> >>
> >> Hi Hanson,
> >>
> >> I've been trying to use the fluent-api JAXB2 plugin with a schema which
> >> makes heavy use of type inheritence. The problem here is that the
> return
> >> types of the withXYZ() methods are not inheritence friendly.
> >>
> >> Let me give an example. Say XJC generates two classes, X and Y, where
> Y
> >> extends X.
> >>
> >> class X {
> >> private String a;
> >>
> >> public String getA() { return a; }
> >> public void setA(String a) { this.a = a; }
> >>
> >> public X withA(String a) {
> >> setA(a);
> >> return this;
> >> }
> >> }
> >>
> >> class Y extends X {
> >>
> >> }
> >>
> >>
> >> Now take some client code:
> >>
> >> Y y = new Y().withA("value");
> >>
> >> Logically, you'd want this to work, but because withA() returns type
> >> X, it
> >> can't be assigned to y.
> >>
> >> I was thinking that the return type of withA() could be altered to use
> >> java5
> >> generics, something like this:
> >>
> >> public <T extends X> T withA(String a) {
> >> setA(a);
> >> return (T) this;
> >> }
> >>
> >> This should allow the result of withA() to be assigned to any variable
> of
> >> type Y without casting or compilation warnings. It does get a bit
> >> confusing, though, when you start chaining them together, with some
> >> withers
> >> in X and some in Y.
> >>
> >> That's my proposal, anyway. I think the plugin codemodel can produce
> >> generic return types, I just don't know how (the codemodel API makes my
> >> brain hurt).
> >>
> >> kenny
> >>
> >>
> >>
>