I just want to extend Foo and FooFactory so that Bar (which extends Foo) will be supplied in some cases.. Simple concept.. hard to do in Sling, I guess.
On Mon, Dec 17, 2012 at 1:22 PM, Ryan Lunka <[email protected]> wrote: > I see a couple things going on here… > > First, I think the reason you are going to see an infinite recursion > situation is because you haven't defined HOW Resource will adapt to Foo. > All the AdapterFactory should do is take an Object and a class and create > a new Object of that Class FROM the adaptable Object you passed in. That > means you need to have a way to create a Foo out of a Resource, if you want > to adapt the latter to the former. The simplest example is by adding a Foo > constructor that takes Resource (i.e. "return (AdapterType) new > Foo(adaptable)" where adaptable is a Resource). If you cannot change the > Foo class, there are probably a variety of other ways to handle it. > > Second, the "if some condition" logic to occasionally return Bar does not > belong in this AdapterFactory. The AdapterFactory should probably only be > responsible for converting one Object to a certain Class. Logic > determining WHAT that Class should be, belongs elsewhere, in whatever code > is calling the adaptTo() function. What you'll probably want to implement > as an AdapterFactory that can adapt Resource to both Foo or Bar, depending > on what class gets called in. Then your "if some condition" logic should > call resource.adaptTo() passing in either of those classes. > > Third, the service may not be registered, and that's why it's not getting > called on resource.adaptTo(). Try using > @Server(value=AdapterFactory.class). > > Hope this helps. Adaptables are not very clearly documented (in my > opinion), so I'm curious if anyone else has feedback as well. It helped me > quite a bit to look at some of the Adaptable and AdatperFactory > implementations in the Sling code base. > > -- > > Ryan D. Lunka > > > > > > On Dec 17, 2012, at 1:06 PM, Sam Lee <[email protected]> wrote: > > > Hey, > > > > Given > > public class Bar implements Foo { > > ... > > } > > > > > > I want to provide AdapterFactory that returns Bar instance when > > resource.adaptTo(Foo.class) is called. > > > > > > Here is my attempt: > > =>8= > > @Component(metatype = false, immediate = true) > > @Service > > @Properties({ > > @Property(name = SlingConstants.PROPERTY_ADAPTABLE_CLASSES, value = > > {"org.apache.sling.api.resource.Resource"}), > > @Property(name = SlingConstants.PROPERTY_ADAPTER_CLASSES, value = > > {"com.example.Foo"}), > > @Property(name = "service.ranking", intValue = -1)//this doesn't seem > > to be observed > > }) > > public class MyAdaptToFoo implements AdapterFactory { > > @Override > > public <AdapterType> AdapterType getAdapter(Object adaptable, > > Class<AdapterType> type) { > > final Resource resource = (Resource) adaptable; > > final Foo foo = resource.adaptTo(Foo.class);//I don't want > infinite > > recursion here. > > if (someCondition) { > > final Bar bar = new Bar(foo); > > return (AdapterType) bar; > > } > > return (AdapterType) foo; > > } > > > > } > > =>8= > > > > first of all, that adapter factory doesn't get called when > > resource.adaptTo(Foo.class); is called.. > > Even if MyAdaptToFoo gets called, I don't want infinite recursion when > its > > .getAdapter() calls resource.adaptTo(Foo.class). > > > > The reason why I'm doing this is because I have a massive code base that > > uses resource.adaptTo(Foo.class).. and I need to augment Foo (with Bar) > in > > some cases. > > > > Is this possible? > >
