Is there a Term ID for each distinctive term indexed in Lucene?

[Tao Cheng]

Hi all,

I found that instead of storing a term ID for a term in the index, Lucene
stores the actual term string value. I am wondering if there ever is such a
"term ID" for each distinctive term indexed in Lucne, similar as a "doc ID"
for each distinctive document indexed in Lucene.

In other words, I am looking for a method like " int termId(string term)" in
the IndexReader, such that it can return my an ID given a term's string
value.

Thanks a lot in advance.

-Tao