In a CTI adapter we are developing, we want to bind user id with an extension when user logs in. So, other users won't bind to the same extension. Is there any JAPI call allow us to achieve this functionality?

I take it that when you say "user", you are talking about an Agent on the Communication Manager.

In this case, you can place an Address Listener on the Huntgroup (skill) address which the agent is logging into. Whenever an agent logs in or out of the huntgroup, your application will receive an ACDAddressEvent event. This event contains the extension of the phone where the agent logged in.

In most systems, there are many huntgroups and it would be difficult to maintain listeners on all of them. Many people create a "dummy" huntgroup and add this as a skill to all agents. They then start a single monitor on this huntgroup. No calls are ever delivered to the dummy huntgroup but the application gets events whenever any agent logs in.

Martin