Stemmer override token filter

Overrides stemming algorithms, by applying a custom mapping, then protecting these terms from being modified by stemmers. Must be placed before any stemming filters.

Rules are mappings in the form of token1[, ..., tokenN] => override.

Setting	Description
`rules`	A list of mapping rules to use.
`rules_path`	A path (either relative to `config` location, orabsolute) to a list of mappings.

Here is an example:

  PUT /my-index-000001 { "settings": { "analysis": { "analyzer": { "my_analyzer": { "tokenizer": "standard", "filter": [ "lowercase", "custom_stems", "porter_stem" ] } }, "filter": { "custom_stems": { "type": "stemmer_override", "rules_path": "analysis/stemmer_override.txt" } } } } }  

Where the file looks like:

 running, runs => run stemmer => stemmer

You can also define the overrides rules inline:

  PUT /my-index-000001 { "settings": { "analysis": { "analyzer": { "my_analyzer": { "tokenizer": "standard", "filter": [ "lowercase", "custom_stems", "porter_stem" ] } }, "filter": { "custom_stems": { "type": "stemmer_override", "rules": [ "running, runs => run", "stemmer => stemmer" ] } } } } }  