[xwiki-users] How to check $xcontext.get(xxxx) is empty?

Hello, I have "some" difficulty with my groovy/velocity code: I manage to pass some parameter between my scheduler/groovy script to my velocity code of my page but I need to check in my velocity code if my parameter exist (or not). http://maven.xwiki.org/site/docs/xwiki-javadoc-4.1.x/com/xpn/xwiki/api/Cont… By exemple, this code doesn't work: {{velocity}} #if ( $xcontext.get("DoCleanup")!=$null)   "DoCleanup" parameter doesn't exist #else   DoCleanup parameter from groovy code is $xcontext.get("DoCleanup") #end {{/velocity}} http://maven.xwiki.org/site/docs/xwiki-javadoc-4.1.x/com/xpn/xwiki/api/Cont… return null if user have PR :-( In fact, in my velocity code I need to detect who's launch the velocity script: groovy code of scheduler or manually launch by the page containing velocity code. Any idea how can I do? Thxs. Pascal B.