A small toolkit of classes that support compare-and-swap semantics for safe mutation of variables.
A small toolkit of classes that support compare-and-swap semantics for safe mutation of variables.
On top of the JVM, this means dealing with lock-free thread-safe programming. Also works on top of Javascript, with Scala.js, for API compatibility purposes and because it's a useful way to box a value.
The backbone of Atomic references is this method:
def compareAndSet(expect: T, update: T): Boolean
This method atomically sets a variable to the update value if it currently holds
the expect value, reporting true on success or false on failure. The classes in this package
also contain methods to get and unconditionally set values.
Building a reference is easy with the provided constructor, which will automatically return the
most specific type needed (in the following sample, that's an AtomicDouble, inheriting from AtomicNumber[T]):
val atomicNumber = Atomic(12.2) atomicNumber.incrementAndGet() // => 13.2
These also provide useful helpers for atomically mutating of values
(i.e. transform, transformAndGet, getAndTransform, etc...) or of numbers of any kind
(incrementAndGet, getAndAdd, etc...).