is there a thread safe version of `mutableMapOf ` i need the kotlinlang #announcements

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Title

l

LS

06/27/2019, 3:46 PM

is there a thread-safe version of

mutableMapOf()

? i need the map to be thread-safe, and also hold its entries in the order of insertion.

k

karelpeeters

06/27/2019, 3:49 PM

Collections.synchronizedMap(LinkedHashMap())

👍 3

Will get you some barebones thread safety.

l

LS

06/27/2019, 3:49 PM

thank you!

k

karelpeeters

06/27/2019, 3:50 PM

But keep in mind that you need to be very careful, eg doing things like

if (x in map) println(map[x])

is still thead-unsafe.

l

LS

06/27/2019, 3:51 PM

I see. thanks

b

bbaldino

06/27/2019, 4:17 PM

is it ever better to use

Collections.synchronizedMap(LinkedHashMap())

over

ConcurrentHashMap

?

k

karelpeeters

06/27/2019, 4:20 PM

If you want insertion order to be kept, otherwise no,

ConcurrentHashMap

is way better.

synchronizedMap

just naively puts a single lock on everything,

ConcurrentHashMap

actually allows things like overlapping reads etc.

b

bbaldino

06/27/2019, 4:21 PM

ah right, i guess synchronizedMap can be used on any map type (like Linked) which could be nice if you don't mind the naive synchronization

3 Views

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