diff --git a/_analyzers/token-filters/index.md b/_analyzers/token-filters/index.md index f4e9c434e7..303bcd4462 100644 --- a/_analyzers/token-filters/index.md +++ b/_analyzers/token-filters/index.md @@ -38,7 +38,7 @@ Token filter | Underlying Lucene token filter| Description `kuromoji_completion` | [JapaneseCompletionFilter](https://lucene.apache.org/core/9_10_0/analysis/kuromoji/org/apache/lucene/analysis/ja/JapaneseCompletionFilter.html) | Adds Japanese romanized terms to the token stream (in addition to the original tokens). Usually used to support autocomplete on Japanese search terms. Note that the filter has a `mode` parameter, which should be set to `index` when used in an index analyzer and `query` when used in a search analyzer. Requires the `analysis-kuromoji` plugin. For information about installing the plugin, see [Additional plugins]({{site.url}}{{site.baseurl}}/install-and-configure/plugins/#additional-plugins). `length` | [LengthFilter](https://lucene.apache.org/core/9_10_0/analysis/common/org/apache/lucene/analysis/miscellaneous/LengthFilter.html) | Removes tokens whose lengths are shorter or longer than the length range specified by `min` and `max`. `limit` | [LimitTokenCountFilter](https://lucene.apache.org/core/9_10_0/analysis/common/org/apache/lucene/analysis/miscellaneous/LimitTokenCountFilter.html) | Limits the number of output tokens. A common use case is to limit the size of document field values based on token count. -`lowercase` | [LowerCaseFilter](https://lucene.apache.org/core/9_10_0/analysis/common/org/apache/lucene/analysis/core/LowerCaseFilter.html) | Converts tokens to lowercase. The default [LowerCaseFilter](https://lucene.apache.org/core/9_10_0/analysis/common/org/apache/lucene/analysis/core/LowerCaseFilter.html) is for the English language. You can set the `language` parameter to `greek` (uses [GreekLowerCaseFilter](https://lucene.apache.org/core/9_10_0/analysis/common/org/apache/lucene/analysis/el/GreekLowerCaseFilter.html)), `irish` (uses [IrishLowerCaseFilter](https://lucene.apache.org/core/9_10_0/analysis/common/org/apache/lucene/analysis/ga/IrishLowerCaseFilter.html)), or `turkish` (uses [TurkishLowerCaseFilter](https://lucene.apache.org/core/9_10_0/analysis/common/org/apache/lucene/analysis/tr/TurkishLowerCaseFilter.html)). +[`lowercase`]({{site.url}}{{site.baseurl}}/analyzers/token-filters/lowercase/) | [LowerCaseFilter](https://lucene.apache.org/core/9_10_0/analysis/common/org/apache/lucene/analysis/core/LowerCaseFilter.html) | Converts tokens to lowercase. The default [LowerCaseFilter](https://lucene.apache.org/core/9_10_0/analysis/common/org/apache/lucene/analysis/core/LowerCaseFilter.html) is for the English language. You can set the `language` parameter to `greek` (uses [GreekLowerCaseFilter](https://lucene.apache.org/core/9_10_0/analysis/common/org/apache/lucene/analysis/el/GreekLowerCaseFilter.html)), `irish` (uses [IrishLowerCaseFilter](https://lucene.apache.org/core/9_10_0/analysis/common/org/apache/lucene/analysis/ga/IrishLowerCaseFilter.html)), or `turkish` (uses [TurkishLowerCaseFilter](https://lucene.apache.org/core/9_10_0/analysis/common/org/apache/lucene/analysis/tr/TurkishLowerCaseFilter.html)). `min_hash` | [MinHashFilter](https://lucene.apache.org/core/9_10_0/analysis/common/org/apache/lucene/analysis/minhash/MinHashFilter.html) | Uses the [MinHash technique](https://en.wikipedia.org/wiki/MinHash) to estimate document similarity. Performs the following operations on a token stream sequentially:
1. Hashes each token in the stream.
2. Assigns the hashes to buckets, keeping only the smallest hashes of each bucket.
3. Outputs the smallest hash from each bucket as a token stream. `multiplexer` | N/A | Emits multiple tokens at the same position. Runs each token through each of the specified filter lists separately and outputs the results as separate tokens. `ngram` | [NGramTokenFilter](https://lucene.apache.org/core/9_10_0/analysis/common/org/apache/lucene/analysis/ngram/NGramTokenFilter.html) | Tokenizes the given token into n-grams of lengths between `min_gram` and `max_gram`. diff --git a/_analyzers/token-filters/lowercase.md b/_analyzers/token-filters/lowercase.md index 041dff2e7b..573f92e284 100644 --- a/_analyzers/token-filters/lowercase.md +++ b/_analyzers/token-filters/lowercase.md @@ -7,35 +7,32 @@ nav_order: 260 # Lowercase token filter -The `lowercase` token filter in OpenSearch is used to limit the number of tokens that are passed through the analysis chain. +The `lowercase` token filter in OpenSearch is used to convert all characters in the token stream to lowercase, making searches case-insensitive. ## Parameters -The `lowercase` token filter in OpenSearch can be configured with the following parameters: - -- `max_token_count`: Maximum number of tokens that will be generated. Default is `1` (Integer, _Optional_) -- `consume_all_tokens`: Use all token, even if result exceeds `max_token_count`. Default is `false` (Boolean, _Optional_) - +The `lowercase` token filter in OpenSearch can be configured with parameter `language`. The possible options are: [`greek`](https://lucene.apache.org/core/8_7_0/analyzers-common/org/apache/lucene/analysis/el/GreekLowerCaseFilter.html), [`irish`](https://lucene.apache.org/core/8_7_0/analyzers-common/org/apache/lucene/analysis/ga/IrishLowerCaseFilter.html) and [`turkish`](https://lucene.apache.org/core/8_7_0/analyzers-common/org/apache/lucene/analysis/tr/TurkishLowerCaseFilter.html). Default is [Lucene’s LowerCaseFilter](https://lucene.apache.org/core/8_7_0/analyzers-common/org/apache/lucene/analysis/core/LowerCaseFilter.html). (String, _Optional_) ## Example -The following example request creates a new index named `my_index` and configures an analyzer with `lowercase` filter: +The following example request creates a new index named `custom_lowercase_example` and configures an analyzer with `lowercase` filter with greek `language`: ```json -PUT my_index +PUT /custom_lowercase_example { "settings": { "analysis": { "analyzer": { - "three_token_limit": { + "greek_lowercase_example": { + "type": "custom", "tokenizer": "standard", - "filter": [ "custom_token_limit" ] + "filter": ["greek_lowercase"] } }, "filter": { - "custom_token_limit": { - "type": "limit", - "max_token_count": 3 + "greek_lowercase": { + "type": "lowercase", + "language": "greek" } } } @@ -49,10 +46,10 @@ PUT my_index Use the following request to examine the tokens generated using the created analyzer: ```json -GET /my_index/_analyze +GET /custom_lowercase_example/_analyze { - "analyzer": "three_token_limit", - "text": "OpenSearch is a powerful and flexible search engine." + "analyzer": "greek_lowercase_example", + "text": "Αθήνα ΕΛΛΑΔΑ" } ``` {% include copy-curl.html %} @@ -63,25 +60,18 @@ The response contains the generated tokens: { "tokens": [ { - "token": "OpenSearch", + "token": "αθηνα", "start_offset": 0, - "end_offset": 10, + "end_offset": 5, "type": "", "position": 0 }, { - "token": "is", - "start_offset": 11, - "end_offset": 13, + "token": "ελλαδα", + "start_offset": 6, + "end_offset": 12, "type": "", "position": 1 - }, - { - "token": "a", - "start_offset": 14, - "end_offset": 15, - "type": "", - "position": 2 } ] }