Extended Virtual Synchrony for Java 1.0 Beta3 review

Extended Virtual Synchrony for Java is a pure Java implementation of the totem single-ring protocol, that provides reliable multicast

License: The Apache License 2.0 File size: 103K Developer: Guglielmo Lichtner

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Extended Virtual Synchrony for Java is a pure Java implementation of the totem single-ring protocol, that provides reliable multicast with totally ordered messages and process group membership

Because of its token-based design, this protocol is unique in achieving effective flow control, and is ideal for implementing replication in small clusters.

Here are some key features of "Extended Virtual Synchrony for Java":
Group membership (configuration) service
Reliable multicast
Total ordering
Flow control
Congestion control
Recovery of messages when a processor fails or joins

Usage:

To use this protocol you need to do the following:

1. Pick integer ids for the nodes in your cluster, e.g. 1,2,3.
2. Pick a port number to send multicast packets on.
3. Pick a multicast address.
4. If you have more than one adapter on each node pick one subnet you want to use.
5. Get an instance of a Connection object.
6. (Probably) create a Listener object.
7. Call open() on the connection.

Some time after open() returns, the method Listener.onConfiguration() is called.
This is to notify the application that a configuration (a ring, or group) has been created.

After this you can expect to receive messages through the onMessage() method.

See the API documentation and src/Example.java for an example.

What's New in This Release:
The previous release incorrectly handled the case of 2 network adapters.
It now forces the user to specify one.
A bug in the code that collected free nodes in the message buffer and put them back in the free list has been fixed.
A bug in updating the last safe message id has been fixed.