code: public Query like(int docNum) throws IOException
     {
        if (fieldNames == null)
        {
           setFieldNames();
        }
  
        return createQuery(retrieveTerms(docNum));
     }
docs: Return a query that will return docs like the passed lucene document ID.
  
  @param docNum the documentID of the lucene doc to generate the 'More Like This" query for.
  @return a query that will return docs like the passed lucene document ID.