Apache Lucene TokenStream过滤器

Question

I have some questions regarding Apache Lucene Library:

1) How can I concatenate two TokenStream objects into one TokenStream object ?

2) Which filter can be used to remove all duplicate tokens (with same value) from a TokenStream object ?

Thanks in Advance

Answer 1

As far as concatenating from two sources, just add two Field instances with the same name to the Document . This is guaranteed to be the same as a single field with the value concatenated.

As far as eliminating duplicated terms, this is not really necessary. Lucene will only count the term frequency for a document in order to score them higher. If you don't need that, you can define your own Similarity instance that implements tf as a constant of 1.

Or, if you need to disable term frequency per field only, you can instantiate the Field with Field.TermVector.NO .