Event based Automatic execution of ODI scenario (or package)

Question

My requirement is that whenever my source XML data file is replaced with new file (file-name remains same by the way; the new file is ftp'ed at this location);
Whenever this event occurs my odi scenario (or package) should get executed automatically.
I don't wish to achieve this using web-services.
I am using ODI 11g.
Any help appreciated.

Answer 1

Thanks a lot Sutirtha Roy.
I achieved what I was trying but one issue is still there:
Following are steps I follow in my ODI Package:
Step 1:
Odi File Wait (Waits for XML input file)
Step 2:
Execute interface (this interface actually does transfer of Src data of XML to Oracle db)
Step 3:
ODI File Move (Moves processed file to some other dir)
---- At this point I see a lock .lck file is created of input file
Step 4:
ODI File Delete (deletes .lck file)
Step 5:
Loop Back to "Odi File Wait" step 1
But after first file is processed and second file is received at src directory the ODI package couldn't load data in db.
The interface got executed as if it was void.
I suspect File is locked in Driver.
The deletion in step 4 didnt help.
How can I resolve it.
Is there a way to execute 'UNLOCK file <fileName>' command on the driver.