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Re: [aspectj-users] Inferred method having a generic as argument [ARGHHH SOLVED]
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If it is a just a generic method being declared on a target type, then
the syntax is as you have:
public <T> void TextComponent.setConverter(Converter<T> c) {
If it is a method that will share the type variables (and thus any
value they are bound to) with the target class then the syntax is:
public void TextComponent<T>.setConverter(Converter<T> c) {
as per:
http://www.eclipse.org/aspectj/doc/released/adk15notebook/generics-inAspectJ5.html#inter-type-declarations
So here is a test program that shows that:
---
class Target<T> {
public void foo(T t) {}
}
aspect X {
public void Target<Z>.goo(Z t) {}
public <Y> void Target.hoo(Y t) {}
}
class ITarget extends Target<Integer> {}
public class Test {
public static void main(String []argv) {
ITarget t= new ITarget();
t.foo(new Integer(5));
// goo can only take Integers
t.goo(new Integer(6));
// t.goo("BANG"); // not allowed
// Both OK, hoo is just a generic method
t.hoo(new Integer(6));
t.hoo("BANG");
}
}
---
Notice goo() cannot be invoked with a String because in ITarget the
type variable has been bound to Integer. hoo() can take anything as
it is just an ordinary generic method. Also notice that the letters
for the type variables dont matter - they are matched by position, so
an ITD on Target with <Z> says 'within this declaration Z matches the
first type variable declared in Target'. We don't rely on name
matching here.
Having said all that, there are open bugs for generic ITDs onto types
when binary weaving, ie. not all from source like the test program
above, and I would not be surprised if you are hitting one of those
when trying to ITD onto TextComponent. That's why I asked if you were
binary weaving in my first reply...
cheers,
Andy.
On 13/04/2008, Simone Gianni <simoneg@xxxxxxxxxx> wrote:
> Hi All,
> I solved the thing, but it is a bit strange how to solve it :
>
> public <T> void TextComponent.setConverter(Converter<T> c) {
>
>
> This is the way it is done in the AspectJ guide to java 5, they always
> declare the <T> even if, being used just in one place, it is not needed
> in a similar java-only method and <?> or nothing could be used instead.
> So, I think this could be a fix in AspectJ, more than just a
> clarification in the docs :)
>
> Simone
>
> Simone Gianni wrote:
> > Hi Andy,
> > Thanks for taking the time for reviewing my code!
> >
> > A couple of differences :
> > - I inferred also the Converter field
> > - TextComponent is a binary class i'm weaving without sources
> >
> > I'm not in office now, but will try it again later and see if i figure
> > out by my self where is the difference.
> >
> > Simone
> >
> > Andy Clement wrote:
> >
> >> >From your description it sounds like a bug, but I can't seem to
> >> recreate it - this file compiles fine for me:
> >>
> >> ---
> >> class TextComponent {
> >> Converter converter;
> >> }
> >>
> >> interface Converter<T> {
> >> public T fromString(String value);
> >> public String toString(T value);
> >> }
> >>
> >> class IntegerConverter implements Converter<Integer> {
> >> public Integer fromString(String value) { return null; }
> >> public String toString(Integer value) { return null; }
> >> }
> >>
> >> aspect X {
> >> Object Converter.component;
> >>
> >> public void TextComponent.setConverter(Converter c) {
> >> this.converter = c;
> >> c.component = this;
> >> }
> >> }
> >>
> >>
> >>
> >> public class Test {
> >> public static void main(String []argv) {
> >> TextComponent tc = new TextComponent() ;
> >> IntegerConverter ic = new IntegerConverter();
> >> tc.setConverter(ic);
> >> }
> >> }
> >> ---
> >>
> >> Can you tell me what I have done differently to you? Is your
> >> TextComponent class generic by any chance? Is it a binary weave into
> >> a library or everything being compiled from source?
> >>
> >> Andy.
> >>
> >> On 11/04/2008, Simone Gianni <simoneg@xxxxxxxxxx> wrote:
> >>
> >>
> >>> Hello all,
> >>> I'm moving my first steps in this beautiful world of AOPized Java, but
> >>> in the last 3 hours I've been facing a problem I don't know how to
> >>> solve. Probably it is just a stupid thing, but still ....
> >>>
> >>> I have a class, called TextComponent, on which I'm trying to add via
> >>> AspectJ a field and a couple of methods. One of the methods is declared
> >>> this way in my aspect :
> >>>
> >>> public void TextComponent.setConverter(Converter c) {
> >>> this.converter = c;
> >>> c.component = this;
> >>> }
> >>>
> >>> Now, Converter is a generic interface :
> >>>
> >>> public interface Converter<T> {
> >>>
> >>> public T fromString(String value);
> >>>
> >>> public String toString(T value);
> >>>
> >>> }
> >>>
> >>>
> >>> Which then has an implementation :
> >>>
> >>> public class IntegerConverter implements Converter<Integer> {
> >>> ....
> >>> }
> >>>
> >>>
> >>> Now, I weave the project containing TextComponent, i get the method
> >>> added, but then when i try to do :
> >>>
> >>> TextComponent tc = new TextComponent();
> >>> IntegerConverter ic = new IntegerConverter();
> >>> tc.setConverter(ic);
> >>>
> >>> I get an error, both from AJDT inside Eclipse and from ajc invoked in
> >>> the Maven build. The error is :
> >>>
> >>> The method setConverter(Converter<T>) in the type TextComponent is not
> >>> applicable for the arguments (IntegerConverter)
> >>>
> >>> Mh, I tried this on a plain class, instead than on an inferred method,
> >>> just to make sure I was not missing something in the generics field. I
> >>> also tried to declare the method differently (like
> >>> setConverter(Converter<?> c) etc..) .. but still it does not work.
> >>>
> >>> Declaring it as setConverter(Object c) and then casting c to a Converter
> >>> (or Converter<?>) works perfectly.
> >>>
> >>> I'm using version 1.5.4 or AspectJ.
> >>>
> >>>
> >>> Any idea?
> >>>
> >>> Simone
> >>> _______________________________________________
> >>> aspectj-users mailing list
> >>> aspectj-users@xxxxxxxxxxx
> >>> https://dev.eclipse.org/mailman/listinfo/aspectj-users
> >>>
> >>>
> >>>
> >> _______________________________________________
> >> aspectj-users mailing list
> >> aspectj-users@xxxxxxxxxxx
> >> https://dev.eclipse.org/mailman/listinfo/aspectj-users
> >>
> >>
> >
> > _______________________________________________
> > aspectj-users mailing list
> > aspectj-users@xxxxxxxxxxx
> > https://dev.eclipse.org/mailman/listinfo/aspectj-users
> >
>
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