Minimal example of raw Clojure's STM use from JRuby

jruby-clojure-stm

require "java"
require "clojure.jar"
java_import "clojure.lang.LockingTransaction"
java_import "clojure.lang.Ref"


counter = Ref.new(0)

puts "Initial value : #{counter.deref}" 


Thread.new {LockingTransaction.run_in_transaction(Proc.new {counter.set counter.deref + 10})}
Thread.new {LockingTransaction.run_in_transaction(Proc.new {sleep 0.5; counter.set counter.deref + 15})}
Thread.new {LockingTransaction.run_in_transaction(Proc.new {sleep 0.1; counter.set counter.deref + 10})}

sleep 2

puts "Final value : #{counter.deref}"