CODEWITHSUNDEEP
javastaticlistenerobserver-pattern
Kevin Parent
Kevin Parent

Reputation: 15

Java Static ArrayList<Listener>

Im working on a small java library and I got a Class named Operation which is a task to process, for now all the tasks are running in a singleThreadExecutor (sequentially).

I made my own Listener and everything to be able to monitor the current operation being processes.

Im storing my observers in a CopyOnWriteArrayList inside my Operation class.

My biggest concern is that i will create a lot of Operation object and i am unlikely to register more than 1-2 observers. I really dont like the idea of creating a CopyOnWriteArrayList for each Operation instance.

I thought about making my CopyOnWriteArrayList static and make a static method to let the observers register to all the operation but i dont know it seems to be a bad design idea overall...

Anyone has a better idea ?

Upvotes: 1

Views: 141

Answers (1)

Steve Kuo
Steve Kuo

Reputation: 63134

I really dont like the idea of creating a CopyOnWriteArrayList for each Operation instance

Why not? It's the correct thing to do. If you are worried about memory or performance, then I suggest you look at the source for CopyOnWriteArrayList - it's more efficient than you think. It's essentially backed by an array, with its Iterator (COWIterator) simply indexes into its backing array. new CopyOnWriteArrayList() starts off with an empty array, so the memory overhead is the CopyOnWriteArrayList itself.

Upvotes: 1

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