On Sat, 28 Sep 2013 11:20:21 -0300, Barry Books <[email protected]> wrote:
I think we are talking about two different things here or there is a
Tapestry feature I don't know about.
I'm not sure you tried to understand what I suggested you in my previous
message.
I'm looking for a feature that will
return a new "Plain Old Object" from an Interface. A simple example:
Map map = objectFactory.build(Map.class);
I already know what you wanted and you just confirmed it now. I just
suggested you to, instead of creating a new service just for instantiating
interfaces, to reuse ObjectProvider and MasterObjectProvider instead. They
have a scope which is a little broader than what you want: give it a type
and it'll return (or not) an object of that type. The only difference is
that in your service the contribution can only provide one type, while an
ObjectProvider can provide many.
Here's one example:
In a module class:
public static void
contributeMasterObjectProvider(OrderedConfiguration<ObjectProvider>
configuration) {
final ObjectProvider mapProvider = new ObjectProvider() {
public <T> T provide(Class<T> objectType,
AnnotationProvider annotationProvider,
ObjectLocator locator) {
Object newObject = null;
if (objectType == Map.class) {
newObject = new HashMap();
}
return (T) newObject;
}
};
configuration.add("Map", mapProvider);
}
Now you can inject the MasterObjectProvider service, which is part of
Tapestry-IoC, and use it this way to get a Map instance:
Map map1 = masterObjectProvider.provide(Map.class, null, null, true);
Map map2 = masterObjectProvider.provide(Map.class, null, null, true);
// prints 'true' because each time you call MasterObjectProvider.provide()
and your ObjectProvider is the one who returns
// the instance, it returns a new one.
System.out.println(map1 != map2);
You can even @Inject Maps now!
@Inject
private Map map1;
@Inject
private Map map2;
Object onActivate(EventContext context) {
System.out.println(map1 != map2); // prints 'true'
...
}
So, in summary, I'm against Barry's suggestion because the
ObjectProvider/MasterObjectProvider dynamic duo already implements what
you want and we would otherwise have two differents services to do the
same thing.
--
Thiago H. de Paula Figueiredo
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