The JActor project implements actors in Java that can process 1 Billion messages per second. JActor 2 supports method calls (without callbacks) for initialization, synchronous and concurrent requests, as well as static typing, all of which make for a more natural coding style when developing applications. Downloads: https://sourceforge.net/projects/jactor/files/ Blog: https://sourceforge.net/p/jactor/blog/ API: http://jactor.sourceforge.net/ VCS: https://github.com/laforge49/JActor/ Slides: http://jactor.sourceforge.net/slides/Actors-in-the-Small-22-feb-2012.pdf Introduction: https://github.com/laforge49/JActor/wiki/Introduction Basics: https://github.com/laforge49/JActor/wiki/JActor-Basics Services - Factories: https://github.com/laforge49/JActor/wiki/Factories Issues: https://github.com/laforge49/JActor/issues/ free(code): http://freecode.com/projects/jactor/ Google groups: http://groups.google.com/group/agilewikidevelopers/ Dependent Projects - Incremental Deserialization https://github.com/laforge49/JID - File Persistence https://github.com/laforge49/JFile - Netty Integration https://github.com/kumarshantanu/JANetty Available on The Central Repository (Maven): http://search.maven.org/#search|ga|1|org.agilewiki So you just need to add this to your POM file: <dependency> <groupId>org.agilewiki.jactor</groupId> <artifactId>jactor</artifactId> <version>3.0.0</version> </dependency> (Be sure to update the version number appropriately, of course.) This project is a reimplementation of a portion of the AsyncFP Scala project: https://github.com/laforge49/Asynchronous-Functional-Programming/wiki Message passing between actors mostly uses 2-way messages (request / response). There are several reasons for this: o With 2-way messaging, sending a request is very similar to a method call with a callback. Most requests are processed synchronously, which is why JActor is so much faster than other actor implementations. o Mailboxes are used mostly when passing messages between threads and are first-class objects. As first-class objects, mailboxes can be used by more than one actor. Passing messages between actors with a common mailbox is always done synchronously and is very fast. o Flow control is implicit to 2-way messaging. Systems with good flow control are generally well-behaved when operating with a full load. Two-way messaging is so much faster than 1-way messaging that it is practical to use 2-way messages when only 1-way messages are needed. There is however one case where you shouldn't use 2-way messages: when events from non-actor code need to be sent to an actor. The JAEvent class is used to do this. Exception Handling The extensive use of callbacks complicates control flow, which is only made worse with some callbacks being executed asynchronously. Exception trapping then can be quite error prone. So exception handling is supported. A default exception handler is also provided which passes any uncaught exceptions that occurred while processing a request back to the actor which sent the request, recursively. Bi-Modal Iterator Loops with 2-way messages can be problematic, as iterations typically must wait for the response from the previous iteration. A bi-modal iterator is provided to cover this. Each iteration takes 5 nanoseconds for synchronous responses and 8 nanoseconds when a response is asynchronous. State Machine State machines are often used with actors and can add considerable clarity to the code. JActor includes classes for composing and executing state machines that are compatible with 2-way messages. Dependency Injection If an actor receives a request of a type that it does not recognize and that actor has been assigned a parent actor, then the request is immediately forwarded to the parent actor. Message Passing Benchmarks Shared Mailbox Across Mailboxes msgs per sec 1,005,340,873 108,511,359 ns per message .99 9.2 CPU cycles per message 5 46 latency (ns) 3.2 25 latency (CPU cycles) 8 66 Test Environment Tests were done on an Intel Core i5 CPU M 540 @ 2.53GHz, which has 4 hardware threads. The times reported were best run in 5. Only standard switch settings were used--there was NO compiler optimization. Contact email: laforge49@gmail.com twitter: @laforge49