CODEWITHSUNDEEP
scala
Vijaykumar Gundavarapu
Vijaykumar Gundavarapu

Reputation: 139

Sharing Mutable Map across akka actor children

I have a large Mutable Map object which occupies so much memory which all the children of the parent need to access or modify values to the same Map.

I am considering just passing the mutable map during child creation as constructor parameters to all the children upon which they can access or modify the map accordingly.

I just wanted to confirm that SCALA actually passes the object reference around and so the Mutable Map will not be copied all over again, instead all the children will be modifying the same Map instance?

Upvotes: 3

Views: 1126

Answers (2)

Soumya Simanta
Soumya Simanta

Reputation: 11741

I have a large Mutable Map object which occupies so much memory which all the children of the parent need to access or modify values to the same Map

This is exactly what Akka shines at compared to other concurrency mechanisms. Encapsulating mutable state inside an Actor and sending messages to the Actor to mutate the state is the correct and recommended approach.

So you need to pass an ActorRef to any actor who needs to modify the map. The cool thing is that other actor can be on a different JVM and it would still work.

This also takes care of your concern the large memory footprint of your Map.

Upvotes: 0

Gangstead
Gangstead

Reputation: 4182

This is a bad idea. The Akka team does not recommend shared mutable state of any kind.

The Akka way to solve your problem would be to make your map immutable and pass it to your children in immutable messages. If you are convinced that the map has to be mutable then have one actor manage the map and have the other actors send messages to it to retrive / update values. There is nothing wrong with mutable state within one actor.

Upvotes: 4

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