Add multiplexer token filter docs #8237

_analyzers/token-filters/index.md

@@ -42,7 +42,7 @@ Token filter | Underlying Lucene token filter|  Description
 `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)).
 [`min_hash`]({{site.url}}{{site.baseurl}}/analyzers/token-filters/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: <br> 1. Hashes each token in the stream. <br> 2. Assigns the hashes to buckets, keeping only the smallest hashes of each bucket. <br> 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.
+[`multiplexer`]({{site.url}}{{site.baseurl}}/analyzers/token-filters/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`]({{site.url}}{{site.baseurl}}/analyzers/token-filters/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`.
 Normalization | `arabic_normalization`: [ArabicNormalizer](https://lucene.apache.org/core/9_10_0/analysis/common/org/apache/lucene/analysis/ar/ArabicNormalizer.html) <br> `german_normalization`: [GermanNormalizationFilter](https://lucene.apache.org/core/9_10_0/analysis/common/org/apache/lucene/analysis/de/GermanNormalizationFilter.html) <br> `hindi_normalization`: [HindiNormalizer](https://lucene.apache.org/core/9_10_0/analysis/common/org/apache/lucene/analysis/hi/HindiNormalizer.html) <br> `indic_normalization`: [IndicNormalizer](https://lucene.apache.org/core/9_10_0/analysis/common/org/apache/lucene/analysis/in/IndicNormalizer.html) <br> `sorani_normalization`: [SoraniNormalizer](https://lucene.apache.org/core/9_10_0/analysis/common/org/apache/lucene/analysis/ckb/SoraniNormalizer.html) <br> `persian_normalization`: [PersianNormalizer](https://lucene.apache.org/core/9_10_0/analysis/common/org/apache/lucene/analysis/fa/PersianNormalizer.html) <br> `scandinavian_normalization` : [ScandinavianNormalizationFilter](https://lucene.apache.org/core/9_10_0/analysis/common/org/apache/lucene/analysis/miscellaneous/ScandinavianNormalizationFilter.html) <br> `scandinavian_folding`: [ScandinavianFoldingFilter](https://lucene.apache.org/core/9_10_0/analysis/common/org/apache/lucene/analysis/miscellaneous/ScandinavianFoldingFilter.html) <br> `serbian_normalization`: [SerbianNormalizationFilter](https://lucene.apache.org/core/9_10_0/analysis/common/org/apache/lucene/analysis/sr/SerbianNormalizationFilter.html) | Normalizes the characters of one of the listed languages.
 [`pattern_capture`]({{site.url}}{{site.baseurl}}/analyzers/token-filters/pattern-capture/) | N/A | Generates a token for every capture group in the provided regular expression. Uses [Java regular expression syntax](https://docs.oracle.com/javase/8/docs/api/java/util/regex/Pattern.html).

_analyzers/token-filters/multiplexer.md

@@ -0,0 +1,165 @@
+---
+layout: default
+title: Multiplexer
+parent: Token filters
+nav_order: 280
+---
+
+# Multiplexer token filter
+
+The `multiplexer` token filter allows you to create multiple versions of the same token by applying different filters. This is useful when you want to analyze the same token in multiple ways. For example, you may want to analyze a token using different stemming, synonyms, or n-gram filters and use all of the generated tokens together. This token filter works by duplicating the token stream and applying different filters to each copy.
+
+The `multiplexer` token filter removes duplicate tokens from the token stream.
+{: .important}
+
+The `multiplexer` token filter does not support multiword `synonym` or `synonym_graph` token filters or `shingle` token filters because they need to analyze not only the current token but also upcoming tokens in order to determine how to transform the input correctly.
+{: .important}
+
+## Parameters
+
+The `multiplexer` token filter can be configured with the following parameters.
+
+Parameter | Required/Optional | Data type | Description
+:--- | :--- | :--- | :--- 
+`filters` | Optional | List of strings | A comma-separated list of token filters to apply to each copy of the token stream. Default is an empty list.
+`preserve_original` | Optional | Boolean | Whether to keep the original token as one of the outputs. Default is `true`.
+
+## Example
+
+The following example request creates a new index named `multiplexer_index` and configures an analyzer with a `multiplexer` filter:
+
+```json
+PUT /multiplexer_index
+{
+  "settings": {
+    "analysis": {
+      "filter": {
+        "english_stemmer": {
+          "type": "stemmer",
+          "name": "english"
+        },
+        "synonym_filter": {
+          "type": "synonym",
+          "synonyms": [
+            "quick,fast"
+          ]
+        },
+        "multiplexer_filter": {
+          "type": "multiplexer",
+          "filters": ["english_stemmer", "synonym_filter"],
+          "preserve_original": true
+        }
+      },
+      "analyzer": {
+        "multiplexer_analyzer": {
+          "type": "custom",
+          "tokenizer": "standard",
+          "filter": [
+            "multiplexer_filter"
+          ]
+        }
+      }
+    }
+  }
+}
+```
+{% include copy-curl.html %}
+
+## Generated tokens
+
+Use the following request to examine the tokens generated using the analyzer:
+
+```json
+POST /multiplexer_index/_analyze
+{
+  "analyzer": "multiplexer_analyzer",
+  "text": "The slow turtle hides from the quick dog"
+}
+```
+{% include copy-curl.html %}
+
+The response contains the generated tokens:
+
+```json
+{
+  "tokens": [
+    {
+      "token": "The",
+      "start_offset": 0,
+      "end_offset": 3,
+      "type": "<ALPHANUM>",
+      "position": 0
+    },
+    {
+      "token": "slow",
+      "start_offset": 4,
+      "end_offset": 8,
+      "type": "<ALPHANUM>",
+      "position": 1
+    },
+    {
+      "token": "turtle",
+      "start_offset": 9,
+      "end_offset": 15,
+      "type": "<ALPHANUM>",
+      "position": 2
+    },
+    {
+      "token": "turtl",
+      "start_offset": 9,
+      "end_offset": 15,
+      "type": "<ALPHANUM>",
+      "position": 2
+    },
+    {
+      "token": "hides",
+      "start_offset": 16,
+      "end_offset": 21,
+      "type": "<ALPHANUM>",
+      "position": 3
+    },
+    {
+      "token": "hide",
+      "start_offset": 16,
+      "end_offset": 21,
+      "type": "<ALPHANUM>",
+      "position": 3
+    },
+    {
+      "token": "from",
+      "start_offset": 22,
+      "end_offset": 26,
+      "type": "<ALPHANUM>",
+      "position": 4
+    },
+    {
+      "token": "the",
+      "start_offset": 27,
+      "end_offset": 30,
+      "type": "<ALPHANUM>",
+      "position": 5
+    },
+    {
+      "token": "quick",
+      "start_offset": 31,
+      "end_offset": 36,
+      "type": "<ALPHANUM>",
+      "position": 6
+    },
+    {
+      "token": "fast",
+      "start_offset": 31,
+      "end_offset": 36,
+      "type": "SYNONYM",
+      "position": 6
+    },
+    {
+      "token": "dog",
+      "start_offset": 37,
+      "end_offset": 40,
+      "type": "<ALPHANUM>",
+      "position": 7
+    }
+  ]
+}
+```