Welcome

Welcome from the creators of Scala STM. We’ve built a lightweight software transactional memory for Scala, inspired by the STMs in Haskell and Clojure while taking advantage of Scala’s power and performance.

ScalaSTM is a single JAR with no dependencies, and includes

An API that supports multiple STM implementations
A reference implementation based on CCSTM
Scalable concurrent sets and maps (with fast snapshots) that can be used inside or outside transactions

ScalaSTM provides a mutable cell called a Ref. If you build a shared data structure using immutable objects and Ref-s, then you can access it from multiple threads or actors. No synchronized, no deadlocks or race conditions, and good scalability. Included are concurrent sets and maps, and we also have an easier and safer replacement for wait and notifyAll.

Learn more…

News

2017 Nov 4 – ScalaSTM version 0.8 published for 2.13.0-M2
(major) 2016 Nov 17 – ScalaSTM version 0.8 released, including
- added 2.12 build
- small TxnLocal improvements
- correctness fix for TArray[Long] and AtomicArray.ofLong
(major) 2014 Apr 17 – ScalaSTM version 0.7 published for 2.11
2014 Apr 7 – ScalaSTM version 0.7 published for 2.11.0-RC4
2014 Mar 20 – ScalaSTM version 0.7 published for 2.11.0-RC3
2014 Mar 7 – ScalaSTM version 0.7 published for 2.11.0-RC1
2014 Feb 4 – ScalaSTM version 0.7 published for 2.11.0-M8
2014 Jan 12 – ScalaSTM version 0.7 published for 2.11.0-M7
2013 Sep 15 – ScalaSTM version 0.7 published for 2.11.0-M5
2013 Jul 28 – ScalaSTM version 0.7 published for 2.11.0-M4
2013 May 22 – ScalaSTM version 0.7 published for 2.11.0-M3
2013 Jan 12 – ScalaSTM version 0.7 published for 2.11.0-M1
(major) 2012 Dec 21 – ScalaSTM version 0.7 released, including
- debugger support via TxnDebuggable
- cooperation with Scala 2.10’s thread pools
- additional convenience methods on Ref, Ref.View, and TxnLocal
2012 Oct 16 – 0.7-SNAPSHOT: Improved support for interactive debuggers via scala.concurrent.stm.TxnDebuggable
2012 Oct 16 – Maven artifacts are now published under the “org.scala-stm” group id (publishing to “org.scala-tools” will continue for current versions), and are now synced automatically with the Maven central repo
(major) 2012 Jul 22 – ScalaSTM version 0.6 released, including
- enhancements to the Java convenience layer
- uses of scala.actors.threadpool.TimeUnit replaced by java.util.concurrent.TimeUnit
(major) 2012 Feb 2 – ScalaSTM version 0.5 released, including
- Java convenience layer scala.concurrent.stm.japi.STM
(major) 2011 Nov 9 – ScalaSTM version 0.4 released, including
- CommitBarrier, support for group commit
- STMBench7 benchmark support
- Better implementation selection
2011 Sep 5 – ScalaSTM 0.3 and 0.4-SNAPSHOT for Scala 2.9.1 released
2011 Jul 8 – 0.4-SNAPSHOT: STMBench7 support. See Benchmarking
(major) 2011 May 12 – ScalaSTM version 0.3 for 2.9.0 released
2011 May 8 – ScalaSTM version 0.3 for 2.9.0.RC4 released
2011 May 6 – ScalaSTM version 0.3 for 2.9.0.RC3 released
(major) 2011 Mar 26 – ScalaSTM version 0.3 released, a pure-Scala software TM library. Included
- Support for Scala 2.9.0.RC1
- Timeouts for retry
2011 Feb 4 – 0.3-SNAPHOT: Bug fixes.
2011 Jan 15 – 0.3-SNAPHOT: Timeouts for retry. See Waiting : Timeouts
2011 Jan 2 – 0.3-SNAPHOT: Bug fixes.
(major) 2010 Dec 27 – ScalaSTM version 0.2 released, a library-based software transactional memory (STM) for Scala. Included
- Performance improvements and bug fixes
- Better TSet, TMap and TxnLocal
- Transaction statistics
2010 Dec 16 – 0.2-SNAPSHOT: Bug fix for while-committing handlers (#3). TxnLocal can now be read and written from while-preparing and while-committing handlers.
2010 Dec 8 – 0.2-SNAPSHOT: Substantial performance improvements, especially for nested atomic blocks. TMap.View and TSet.View are integrated with Scala collection class hierarchy.
(major) 2010 Dec 6 – ScalaSTM version 0.1 released, a library-based software transactional memory (STM) for Scala. Get it…