To modify a location, the modeling language was extended with
constructs called location modi?¬?ers. They allow adding and removing locations from
LANGUAGE FOR MODELING CALL PROCESSING SERVICES 105
the location set. Following the XML schema, three different modeling objects were
added to the language:
. Explicit Location are set by adding the given URL address to the location set.
The location can be further re?¬?ned with its priority in the location set and with
an optional property to choose if the existing location set is cleared before
adding a new location. Thus the property speci?¬?ed here is used as an argument
to access the CPL server??™s service.
. Locations can also be set from external sources. For this purpose, CPL has a
location lookup concept. This was represented as its own concept in the
language. Location lookup has three properties: Mandatory Source to give a
location from which the CPL server can ask for the location, Time-out to
specify the time to keep trying before abandoning the lookup, and whether the
current location set needs to be cleared before adding the new location.
. A call processing service can also remove locations from the location set. For
this purpose, the Location removal concept has a property to specify the
location as a string value. If the value is left empty, the default in the concept, all
locations are removed from the location set.
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