Method and apparatus for synchronizing contact data stores

1 . A mobile device for synchronizing contact data stores comprising:

a) a host, said host having:

i. a database for storing contact records; and

ii. a contact application communicating with said database, said contact application being capable of altering said contact records;

b) a client, said client having:

i. a client contact application, said client contact application being capable of altering said contact records; and

ii. a client data manager communicating with said client contact application for storing contact records;

c) a state machine for communicating between said client and said host;

d) a client listener to determine when a change has been made at said client and propagate said change to said host through said state machine; and

e) a host listener to determine when a client record has been changed in said database and propagate said change to said client,

wherein said database and said client data manager are synchronized through said state machine.

2 . The mobile device of claim 1 further comprising a database management system between said contact application and said database.

3 . The mobile device of claim 2 further comprising a client database communicating with said client data manager and maintaining synchronized contact records with said database in said host.

4 . The mobile device of claim 1 , wherein altering said contact records includes adding a new contact record, deleting and existing contact record or modifying an existing contact record.

5 . The mobile device of claim 1 , further comprising a communications system for communicating with an external database.

6 . The mobile device of claim 5 , wherein the mobile device further includes memory for storing a variable, said variable indicating whether said mobile device is enabled to synchronize with said external database.

7 . The mobile device of claim 6 , wherein the client database becomes a master database when said variable indicates that said mobile device is enabled to synchronize with said external database.

8 . A method for synchronizing contact data stores in a mobile device having a host database and a client database, the method comprising:

a) designating one of the host database and client database a master database and the other of the host database and client database as a slave database;

b) configuring a listening application to monitor the master database;

c) if the master database changes, sending a message from the listening application, through a state machine, to the slave database with the change in the master database;

d) setting a data manager to monitor the slave database; and

e) if the data manager detects a change request for the slave database, sending a change message to the master database.

9 . The method of claim 8 , wherein said designating step is determined based on a variable set at the mobile device.

10 . The method of claim 9 , wherein the variable designates that the mobile device can synchronize with an external database.

11 . The method of claim 10 , wherein the client database becomes the master database if the variable designates the mobile device can synchronize with an external database.

12 . The method of claim 8 , wherein the host and client databases are address books.

13 . The method of claim 12 , wherein changes to the host and client databases originate at a contact application.

14 . The method of claim 10 , further comprising the step of synchronizing the client database with the external database.