A white board service that represents a listener for endpoints.
An Endpoint Listener represents a participant in the distributed model that
is interested in Endpoint Descriptions.
This white board service can be used in many different scenarios. However,
the primary use case is to allow a remote manager to be informed of Endpoint
Descriptions available in the network and inform the network about available
Both the network bundle and the manager bundle register an Endpoint Listener
service. The manager informs the network bundle about Endpoints that it
creates. The network bundles then uses a protocol like SLP to announce these
local end-points to the network.
If the network bundle discovers a new Endpoint through its discovery
protocol, then it sends an Endpoint Description to all the Endpoint Listener
services that are registered (except its own) that have specified an interest
in that endpoint.
Endpoint Listener services can express their scope
with the service
. This service property is a list of
filters. An Endpoint Description should only be given to a Endpoint Listener
when there is at least one filter that matches the Endpoint Description
This filter model is quite flexible. For example, a discovery bundle is only
interested in locally originating Endpoint Descriptions. The following filter
ensure that it only sees local endpoints.
In the same vein, a manager that is only interested in remote Endpoint
Descriptions can use a filter like:
Where in both cases, the given UUID is the UUID of the local framework that
can be found in the Framework properties.
The Endpoint Listener's scope maps very well to the service hooks. A manager
can just register all filters found from the Listener Hook as its scope. This
will automatically provide it with all known endpoints that match the given
scope, without having to inspect the filter string.
In general, when an Endpoint Description is discovered, it should be
dispatched to all registered Endpoint Listener services. If a new Endpoint
Listener is registered, it should be informed about all currently known
Endpoints that match its scope. If a getter of the Endpoint Listener service
is unregistered, then all its registered Endpoint Description objects must be
The Endpoint Listener models a best effort
bundles should do their utmost to keep the listeners up to date, but
implementers should realize that many endpoints come through unreliable
- $Id: 8feaa377aecc7db74348c2c1b26ce7cd9fe64fea $