Its historical - probably at least 10 years old in origin. Only warning I would give is that ConcurrentHashMap can be slow and a memory hog for lots of inserts deletes - synchronisation around a HashMap may perform better - would be worth validating that though
> On 1 Apr 2015, at 20:57, Kevin Burton <bur...@spinn3r.com> wrote: > > I’m curious why MemoryMessageStore is backed by a LinkedHashMap and not a > queue data structure. > > Does anyone know? It might be just do to the age. > > The one thing that could break it is: > > public void updateMessage(Message message) > > .. which updates the message by ID. But make we could keep two indexes, a > queue and a concurrent map. but I think updateMessage is only called for > persistent messages. > > I’m asking because I’m investigating implementing JMS priority in the > memory store. If it was backed by a priority queue (lower case, not > necessarily proposing the PriorityQueue but more of > java.util.concurrent.PriorityBlockingQueue or maybe even something from > disruptor.) > > It would be trivial to implement JMS priority at that point I think. > Messages would just be returned based on their JMS priority then FIFO order. > > Also, this class uses a lot of synchronization which would be removed if it > was refactored this way. > > I’m still experimenting with this idea. I still have to fix the 5.11.x > regressions we’ve found. > > thoughts? > > Kevin > > -- > > Founder/CEO Spinn3r.com > Location: *San Francisco, CA* > blog: http://burtonator.wordpress.com > … or check out my Google+ profile > <https://plus.google.com/102718274791889610666/posts> > <http://spinn3r.com>
