| Re: [aspectj-users] Newbie question on inter-type member declarations |
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Hi Are-
> I'm wondering if it's possible in AspectJ to add inter-type member
declarations based on pointcuts?
No. Your case is classic generative programming, of applying a rule
to create code.
AspectJ if anything is moving away from that. ITMD's since AspectJ
1.1 have their type
resolved at compile-time, mainly to support incremental weaving. We
thought that it
would be better to strongly separate generative programming from AspectJ
than
to continue or expand support for it.
You might get as much convenience from a utility - variants:
String.valueOf(x)
Renderer.render(int x)
getRenderer(y).render(y.x, "fieldname")
AspectJ could parameterize around the field name for lazy
initialization:
String around(Item item) : get(String *AsString) &&
target(Item) {
String result = proceed(item);
if (result == null) {
// reflectively set field,
based on utility call, keyed off field signature
}
return result;
}
Or perhaps for each domain element viewable on a web page: interface IWeb { String fieldAsString(String fieldName);
}
aspect ImplementingIWeb {
declare parents {domainClasses}
implement IWeb;
public String
IWeb.fieldAsString(String fieldName) {
//
default, reflective implementation
}
}
/** override default implementation for Item */
aspect ImplementingIWebForItem {
declare precedence
ImplementingIWebForItem, ImplementingIWeb;
public String
Item.fieldAsString(String fieldName) {
//
custom Item implementation
}
}
(I personally don't like any of these options, but they might be worth
considering.) Hope this helps -
Wes
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