How to identify workspace that is partially loaded ?

Hello,
User can use load rules to load part of the project, but the builder algorithm must know about the project structure.
is there a way (API) to know (programmatically or command line) that the workspace is just partially loaded?
* using Eclipse client, i can see comment on the project navigetor that the project is not fully loaded.
i use server side plugins.
Thanks,
Yehiel