System and method for calendar presence retrieval

1 . A presence system for retrieving and using calendar presence information of presentities, comprising:

a calendar agent operable to generate queries for calendar schedule information associated with said presentities to calendar servers, to receive said calendar schedule information for said presentities from said calendar servers and to process said calendar schedule information to convert said calendar schedule information into said calendar presence information;

calendar interfaces, each configured to communicate with said calendar agent via a first protocol to receive said queries and provide said calendar schedule information to said calendar agent, and each configured to communicate with a respective one of said calendar servers via a respective second protocol that is different from said first protocol to provide respective ones of said queries to said respective calendar server and to receive from said respective calendar server said calendar schedule information; and

a cache maintained by said calendar agent for storing said calendar presence information of said pres entities;

wherein said calendar agent is operable to provide real-time updates of said calendar presence information to watchers of said presentities using said calendar presence information stored in said cache.

2 . The presence system of claim 1 , wherein each of said calendar interfaces comprises:

a query handler configured to communicate with said respective calendar server and said calendar agent to convert messages between a format associated with said first protocol and a format associated with said respective second protocol.

3 . The presence system of claim 2 , wherein each of said calendar interfaces further comprises:

an event sink configured to dynamically receive said calendar schedule information and to provide said calendar schedule information to said calendar agent.

4 . The presence system of claim 3 , wherein said event sink of one of said calendar interfaces receives said calendar schedule information from said respective calendar server in response to providing a respective one of said queries to said respective calendar server.

5 . The presence system of claim 3 , wherein said calendar schedule information includes updated calendar schedule information, and wherein said event sink of one of said calendar interfaces receives said updated calendar schedule information from said respective calendar server asynchronously in response to changes in said calendar schedule information of one or more of said presentities associated with said respective calendar server.

6 . The presence system of claim 1 , wherein each of said queries requests said calendar schedule information for one or more of said presentities.

7 . The presence system of claim 1 , wherein one of said queries to a first one of said calendar interfaces requests said first calendar interface to monitor a list of said presentities for said calendar schedule information, add a presentity to said list, remove a presentity from said list or retrieve from said respective calendar server said calendar schedule information.

8 . The presence system of claim 7 , wherein said first calendar interface is further configured to subscribe to said respective calendar server to monitor said list of said presentities for said calendar schedule information.

9 - 10 . (canceled)

11 . The presence system of claim 1 , wherein:

said calendar presence information includes a respective meeting object for each meeting scheduled in said calendar servers for said presentities, each said meeting object including information associated with said respective meeting;

said calendar agent is further operable to assign a meeting identifier to each said meeting object; and

said cache includes indexes linking each said meeting identifier to said respective meeting object.

12 . The presence system of claim 11 , wherein:

said calendar presence information further includes a meeting start time and a meeting end time for each said respective meeting; and

said cache includes indexes linking said meeting identifiers to said respective meeting start time and said respective meeting end time.

13 . The presence system of claim 12 , wherein:

said calendar presence information further includes presentity identities identifying each presentity associated with each said respective meeting; and

said cache includes indexes linking said meeting identifiers to said respective presentity identities.

14 . The presence system of claim 1 , further comprising:

a presence server for collecting and storing presence information including said calendar presence information on said presentities and providing said presence information of said presentities to watchers of said presentities.

15 - 18 . (canceled)

19 . A method for retrieving and using calendar presence information of presentities, comprising the steps of:

generating queries for calendar schedule information associated with said presentities in a first format;

converting each of said queries from said first format to a respective second format associated with a respective calendar application maintaining said calendar schedule information of said presentities, said second format being different from said first format;

retrieving said calendar schedule information from each of said calendar applications in said respective second format;

converting said calendar schedule information from said respective second format to said first format for processing of said calendar schedule information to convert said calendar schedule information to said calendar presence information;

storing said calendar presence information of said presentities in a cache; and

providing real-time updates of said calendar presence information to watchers of said presentities using said calendar presence information in said cache.

20 . The method of claim 19 , wherein said retrieving said calendar schedule information further includes receiving said calendar schedule information from a respective one of said calendar servers in response to providing a respective one of said queries to said respective calendar server.

21 . The method of claim 19 , wherein said calendar schedule information includes updated calendar schedule information, and wherein said retrieving said calendar schedule information further includes:

receiving said updated calendar schedule information from a respective one of said calendar servers asynchronously in response to changes in said calendar schedule information of one or more of said presentities associated with said respective calendar server.

22 . The method of claim 19 , wherein said generating said queries further includes:

generating one of said queries to request monitoring a list of said presentities associated with a respective one of said calendar servers for said calendar schedule information, adding a presentity to said list, removing a presentity from said list or retrieving from said respective calendar server said calendar schedule information.

23 . The method of claim 22 , wherein said retrieving further includes:

subscribing to said respective calendar server to monitor said list of said presentities for said calendar schedule information.

24 . (canceled)