Normally to add a Directory to your Lucene Search Directory one would add

to hibernate.cfg.xml

and to retrieve this from the FullTextSession one would write

My question is , Is it possible to set the Directory at runtime, instead of having to put the value inside a hibernate.cfg.xml

Hi,

I guess there are two things one could do. Firstly you could configure progammatically using Hibernate's configuration API. You could then set the hibernate.search.default.indexBase property at startup.
Secondly, you could implement a custom DirectoryProvider, maybe by extending the provided FSDirectoryProvider. You can then specify your custom provider by setting the property: hibernate.search.default.directory_provider.

It really depends on what you are trying to do?

--Hardy