Scala - Mutable thread safe collections

Question

I need a mutable thread safe Map and a mutable thread safe List in Scala. I know that the immutable collections are thread safe by default. But, I need to update my collections very often because of which I couldn't use immutable. Also I need my threadsafe mutable Map to maintain the insertion order.

Right now am using the map below

val map = scala.collection.mutable.LinkedHashMap[String,Any]() 

This map maintains the insertion order and is mutable. How do I make it thread safe?

Answer 1

Fast hint for those coming to this in 2018 or later:

import java.util.concurrent.ConcurrentHashMap  val m: ConcurrentHashMap[String,MyClass] = new ConcurrentHashMap 

Answer 2

1. You're duplicating topics....

2. As was mentioned by AlexIv in his answer, there's a trait you can mix in if you want thread safety. There's another way though:

   val synchronizedMap = new scala.collection.mutable.LinkedHashMap[String, Any]() with scala.collection.mutable.SynchronizedMap[String, Any] 

That should give you the map with synchronization on each access. Easy, but might not meet the performance requirements. If so, it would be probably easier to create a custom class extending the LinkedHashMap, mixing in the concurrent.Map trait (as was suggested) and provide the implementation of relevant methods, i.e: putIfAbsent, remove replace (2 overloads).