Adding External Metadata to pdf document

[Jana, Kumar Raja]

Hi,
 
I need to add some external metadata along with the documents I send to
ExtractingRequestHandler. Can someone please tell me how do i achieve
this?
 
E.g. Say I need to index the file abc.pdf. I want to add some more
additional information to the metadata such as Category = Alphabets,
Catalog_ID = 1213123, Owner = Mr. X, Date_of_Purchase = someday, etc.
 
Thanks,
Kumar