check document is opened by other user xpages

Question

I m working with xpages for following scenario. I have one agent that will update the value to one of the field of datasource from notesview. sometimes, while one user is opening the datasource via xpage and other user run the agent in the same time. at that time, agent can run and update the field of datasource. but from the xpages side, we can catch the exception for the document is modified by other user and cannot save the xpages. i would like to prevent this from agent side. i would like to know whether there is a way to know that document is opened by one of the user from agent side, so that agent wont update the value to that datasource. thank for your help.

Answer 1

First of all: mixing agent and XPages is more trouble than it is worth, you are better off converting your agent code into a Java class (and pay the technical debt accumulated over time in the agent).

One BIG reason: an agent and XPages do not share anything other than the document in memory (if handed over) on that one user's session.

If you launch the agent from an XPage: you can use an ApplicationScope variable (e.g. a java.util.HashMap) that you fill with the unid and username when a user opens a document. Before you launch that agent, you check the scope if the unid is inside with a different username. If yes, don't run the agent.

You need to build a mechanism to expire and renew these locks otherwise you end up with dead lock entries.

If the agent is launched directly or on schedule things get a little more complicated. You could implement a web service servlet that handles the locks since both XPages and agents can talk to a web service.