Pros and Cons of Listeners as WeakReferences

Question

What are the pros and cons of keeping listeners as WeakReferences.

The big \'Pro\' of course is that:

Adding a listener as a WeakReference means the listener

Answer 1

I can't think of any legitimate use case for using WeakReferences for listeners, unless somehow your use case involves listeners that explicitly shouldn't exist after the next GC cycle (that use case, of course, would be VM/platform specific).

It's possible to envision a slightly more legitimate use case for SoftReferences, where the listeners are optional, but take up a lot of heap and should be the first to go when free heap size starts getting dicey. Some sort of optional caching or other type of assisting listener, I suppose, could be a candidate. Even then it seems like you'd want the internals of the listeners to utilize the SoftReferences, not the link between the listener and listenee.

Generally if you're using a persistent listener pattern, though, the listeners are non-optional, so asking this question may be a symptom that you need to reconsider your architecture.

Is this an academic question, or do you have a practical situation you're trying to address? If it's a practical situation I'd love to hear what it is -- and you could probably get more, less abstract advice on how to solve it.