Anyone have a good way of iterating through a `Con...

# server

[Brian Estrada]

Anyone have a good way of iterating through a ConcurrentHashMap and removing items at the same time?

[Sam]

The basic pattern is this:

val iterator = map.entries.iterator()
while (iterator.hasNext()) {
    iterator.next()
    iterator.remove()
}

I think concurrent hash maps support removal via the iterator, though not all collections do

[Chris Lee]

yea. the specifics will depend on the atomicity needed - should the whole operation (iteration + removals) be atomic, or can some level of staleness be tolerated?

[ephemient]

you can usually use retainAll/removeAll (with a predicate) instead of working with the iterator directly