Releases

The latest release of ScalaSTM is version 0.7. To get it you can

follow sbt instructions or maven2 instructions
download a prebuilt JAR
- for 2.13.0-M2: scala-stm_2.13.0-M2-0.8.jar
- for all 2.12 releases: scala-stm_2.12-0.8.jar
- for all 2.11 releases: scala-stm_2.11-0.8.jar

Release notes

Changes between 0.7 and 0.8:

correctness fix for TArray[Long] and AtomicArray.ofLong.
small improvement to TxnLocal interface.
add 2.12 build and remove 2.10 build.
add deprecated message about incomplete deadlock detection for CommitBarrier.

Changes between 0.6 and 0.7:

better support for interactive debuggers, via TxnDebuggable and atomic.unrecorded. IntelliJ IDEA and Eclipse can now watch Ref values inside a transaction without affecting the read or write sets.
ScalaSTM cooperates with 2.10’s scala.concurrent.BlockingContext.
added transformAndExtract to Ref, Ref.View, and TxnLocal, which allows an arbitrary value to be returned from the transformation function.
added transformAndGet and getAndTransform to Ref and TxnLocal, previously these were only defined for Ref.View.

Changes between 0.5 and 0.6:

retry and retryFor added to the Java compatibility interface.
uses of scala.actor.threadpool.TimeUnit in the interface replaced with java.util.concurrent.TimeUnit to avoid making ScalaSTM depend on the separate scala-actors.jar in Scala 2.10.

Changes between 0.4 and 0.5

scala.concurrent.stm.japi.STM added, which makes it much cleaner to access ScalaSTM functionality from Java.

Changes between 0.3 and 0.4

CommitBarrier added, which allows multiple atomic blocks (each on its own thread) to commit together.
Small performance improvements.
STMBench7 benchmark support added.
Automatic selection of STMImpl in most cases.

Changes between 0.2 and 0.3

Support for Scala 2.9.0.
Timeouts for retry. See Waiting : Timeouts.
Bug fixes and contention management improvements
- #11 – fix for two-Ref form of compareAndSet;
- #12 – rare StackOverflowException under heavy contention and true nesting;
- #13 – contention management improvements;
- #14 – fix for external decision support;
- #15 – NPE if a post-decision handler threw an exception;
- #18 – atomicity can be broken by TMap copy-on-write mechanism; and
- #19 – potential deadlock between pessimistic readers.

Changes between 0.1 and 0.2

Substantial performance improvements, especially for nested atomic blocks. Nested atomic blocks without orAtomic are optimistically subsumed (run directly in their parent transaction), then retried without subsumption if partial rollback is needed.
TSet.View and TMap.View are integrated into the Scala collection class hierarchy, with factory companion objects and Builder and CanBuildFrom instances.
A fix for whileCommitting handlers (issue #3).
TxnLocal can now be read and written from while-preparing and while-committing handlers. Combining TxnLocal and life-cycle handlers is now more concise.
Transaction statistics can be enabled for the default algorithm with the VM argument -Dccstm.stats=1 (for more information see the ScalaDoc for scala.concurrent.stm.ccstm.CCSTM).

SBT

Tell sbt about a dependency on ScalaSTM by adding a library dependency to your build.sbt file (or a Scala build file)

libraryDependencies += ("org.scala-stm" %% "scala-stm" % "0.8")

sbt update will then download the correct scala-stm JAR and use it for building.

Maven2

Separate artifacts are published for each version of Scala, so the desired Scala version (such as 2.12) must be included in the artifactId for Maven (sbt automatically handles this). The ScalaSTM dependency for your pom.xml is

<dependencies>
  <dependency>
    <groupId>org.scala-stm</groupId>
    <artifactId>scala-stm_2.12</artifactId>
    <version>0.8</version>
  </dependency>
</dependencies>

The deployment tests inside the ScalaSTM source include a complete pom.xml