Re: [xwiki-devs] [VOTE] Using ThreadLocal vs passing the Context around for all method calls?

I don't really like the ThreadLocal because it seems too much "nice" to be true and I wonder what is the problem :) But, after some studying, it seems ThreadLocal might be the only clever solution in Java for propagating the container without passing it to all functions. Apparently, speaking performace, ThreadLocal seems to be ok. The only thing to take care about is cleaning the ThreadLocal to prevent memory leaks... Naturally, it implies the strong association between unit of work and thread but as Vincent said, today, there is not many usecases where a unit of work could need to be multi-threaded. The only case I can see is the case when a component would need to call other components which run in other threads because they perform heavy or asynchronous operations. For example, imagine you call an external indexing engine or a distributed component. And even in this case, I wonder if there is a problem with ThreadLocal. In fact, the only important thing a component requires is the injection of the container at the right time and in the right scope... and also a safe getter... Using ThreadLocal, it would be something like (without taking into account previous context storing/restoring, reduction of lookups and memory leaks) Component.setContainer(Container c) { threadLocal.set(c); } and Container Component.getContainer() { return threadLocal.get(); } Using the Servlet model, interceptors might be a simple way to inject the right container in the component... I think ThreadLocal will solve 80-90% of our usecases and for the remaining cases, we will use the plain old Container passed using the injection or even as a function parameter to the component... So I VOTE +1 if you keep code as independent as possible from ThreadLocal using some kind of ContainerInjector from which Component would inherit... Regards Pascal On 4/13/08, Ludovic Dubost <ludovic(a)xwiki.org> wrote: