How does Jtrix differ from Jini, and can they interoperate?
- Isolation. Service code and client code are
completely isolated. A big win here is for versioning.
Suppose your Jini client used parser.jar version
1.1 and a Jini service used parser.jar version 1.2.
Then, because the client and service sit in the
same space, your application would fall over. With
Jtrix the client and service code are completely
isolated, and can use completely different versions
of libraries without fear. They only need to share
the same version of the (very minimal) base library
and of course talk via an agreed service interface.
- Security. A consequence of isolation. In Jini
it is possible for the Jini client to sandbox itself
against the Jini service code, but the Jini service
has to trust the Jini client. In Jtrix no trust is
assumed. The client and server cannot interfere
with each other in any way.
- Hosting service. A service that is important
to Jtrix is the "hosting service". The idea is that
an application can find somewhere else to run
and copy itself into that space. This way an
application can scale up to meet demand, distributing
itself as needed. This is important for Web Services
which need to respond to demand globally.
With Jini a hosting service isn't practical.
- Accountability. If you're going to allow an alien application to run on your system you must be able to monitor its resource usage (CPU, memory, disk, network connections, etc). This way you can bill the user fairly. Without this a Web Service won't be able to expand to another cluster because the cluster owner wouldn't be able to run a business viably. Jtrix has accountability built in at the base level.
These were considered key for Jtrix, and are so fundamental to any system that extending Jini would not have been possible. Much of Jtrix's core code is all about protecting one component from any other.
Since Jini and Jtrix share the same external aims they are compatible. A very sensible thing would be to have a Jtrix service export a Jini service by default. A Jtrix netlet (application component) can happily use a Jini service.