Grass Valley iControl Services Gateway - Manual (Page 26)

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Appendix C JINI™ Technology Primer (
www.sun.com/jini )
Jini network technology provides simple mechanisms which enable devices to plug together to form an
impromptu community -- a community put together without any planning, installation, or human intervention.
Each device provides services that other devices in the community may use. These devices provide their own
interfaces, which ensures reliability and compatibility.
Jini technology uses a lookup service with which devices and services register. When a device plugs in,
it goes through an add-in protocol, called discovery and join-in. The device first locates the lookup
service (discovery) and then uploads an object that implements all of its services' interfaces (join).
To use a service, a person or a program locates it using the lookup service. The service's object is
copied from the lookup service to the requesting device where it will be used. The lookup service acts as
an intermediary to connect a client looking for a service with that service. Once the connection is made,
the lookup service is not involved in any of the resulting interactions between that client and that service.
It doesn't matter where a service is implemented -- compatibility is ensured because each service
provides everything needed to interact with it. There is no central repository of drivers, or anything else
for that matter.
The Java programming language is the key to making Jini technology work. Devices in a network
employing Jini technology are tied together using Java Remote Method Invocation (RMI). By using the
Java programming language, a Jini network architecture is secure. The discovery and join protocols, as
well as the lookup service, depend on the ability to move Java objects, including their code, between
Java virtual machines.
Jini technology not only defines a set of protocols for discovery, join, and lookup, but also a leasing and
transaction mechanism to provide resilience in a dynamic networked environment. The underlying
technology and services architecture is powerful enough to build a fully distributed system on a network
of workstations. And the Jini network infrastructure is small enough that a community of devices enabled
by Jini network software can be built out of the simplest devices. For example, it is entirely feasible to
build such a device community out of home entertainment devices or a few cellular telephones with no
"computer" in sight.