Jetlang

Jetlang provides a high performance java threading library. The library is based upon Retlang.

The library is a complement to the java.util.concurrent package introduced in 1.5 and should be used for message based concurrency similar to event based actors in Scala.

The library does not provide remote messaging capabilities. It is designed specifically for high performance in-memory messaging. Features

• All messages to a particular Fiber are delivered sequentially. Components can easily keep state without synchronizing data access or worrying about thread races.
• Single Fiber interface that can be backed by a dedicated thread or a thread pool.
• Supports single or multiple subscribers for messages.
• Subscriptions for single events or event batching
• Single or recurring event scheduling
• High performance design optimized for low latency and high scalability
• Publishing is thread safe, allowing easy integration with other threading models.
• Low Lock Contention - Minimizing lock contention is critical for performance. Other concurrency solutions are limited by a single lock typically on a central thread pool or message queue. Jetlang is optimized for low lock contention. Without a central bottleneck, performance easily scales to the needs of the application.
• Powerful Async Request/Reply Support
• Single jar with no dependencies except the jdk (1.6+)
• Integrates with any JVM language - jruby, scala, clojure, groovy, etc
• Distributed Messaging - Jetlang Remoting

Example

Fiber fiber = new ThreadFiber();
fiber.start();
final CountDownLatch latch = new CountDownLatch(2);
Runnable toRun = new Runnable(){
    public void run(){
        latch.countDown();
    }
};
//enqueue runnable for execution
fiber.execute(toRun);
//repeat to trigger latch a 2nd time
fiber.execute(toRun);
latch.await(10, TimeUnit.SECONDS);
//shutdown thread
fiber.dispose();

Channel Example

    // start thread backed receiver. 
    // Lighweight fibers can also be created using a thread pool
    Fiber receiver = new ThreadFiber();
    receiver.start();

    // create java.util.concurrent.CountDownLatch to notify when message arrives
    final CountDownLatch latch = new CountDownLatch(1);

    // create channel to message between threads
    Channel<String> channel = new MemoryChannel<String>();

    Callback<String> onMsg = new Callback<String>() {
        public void onMessage(String message) {
            //open latch
            latch.countDown();
        }
    };
    //add subscription for message on receiver thread
    channel.subscribe(receiver, onMsg);

    //publish message to receive thread. the publish method is thread safe.
    channel.publish("Hello");

    //wait for receiving thread to receive message
    latch.await(10, TimeUnit.SECONDS);

    //shutdown thread
    receiver.dispose();

##Using with Maven

Jetlang is in the central maven repository as of 0.2.9

https://repo1.maven.org/maven2/org/jetlang/jetlang/

To use Jetlang, add the following dependency. Replace DESIRED_VERSION_HERE with the version you would like to use.

    <project>
        ...
        <dependencies>
            ...
            <dependency>
                <groupId>org.jetlang</groupId>
                <artifactId>jetlang</artifactId>
                <version>_DESIRED_VERSION_HERE_</version>
            </dependency>
            ...
        </dependencies>
        ...
    </project>

##Dev Mailing List

https://groups.google.com/forum/#!forum/jetlang-dev

Releasing with Maven

mvn release:prepare release:perform