[LUCENE-4817] Add KeywordRepeaterFilter to emit tokens twice once as keyword and once not as keyword

• Type: Improvement
• Status: Closed
• Priority: Minor
• Resolution: Fixed
• Affects Version/s: 4.1
• Fix Version/s: 4.3, 6.0
• Component/s: modules/analysis
• Lucene Fields: New, Patch Available
• Assignee: Unassigned
• Reporter: Simon Willnauer
• Created: 07/Mar/13 20:58
• Updated: 28/Aug/22 13:40
• Resolved: 08/Mar/13 10:49

Description

if you want to have a stemmed and an unstemmed version of a token one for recall and one for precision you have to do two fields today in most of the cases. Yet, most of the stemmers respect the keyword attribute so we could add a token filter that emits the same token twice once as keyword and once plain. Folks would most likely need to combine this RemoveDuplicatesTokenFilter but that way we can have stemmed and unstemmed version in the same field.

Issue Links

• supercedes: SOLR-3231 Add the ability to KStemmer to preserve the original token when stemming