add trim token filter docs #8449 (#8461)

* add trim token filter docs #8449 Signed-off-by: Anton Rubin <[email protected]> * updating the nav_order Signed-off-by: Anton Rubin <[email protected]> * Doc review Signed-off-by: Fanit Kolchina <[email protected]> * Apply suggestions from code review Co-authored-by: Nathan Bower <[email protected]> Signed-off-by: kolchfa-aws <[email protected]> --------- Signed-off-by: Anton Rubin <[email protected]> Signed-off-by: Fanit Kolchina <[email protected]> Signed-off-by: kolchfa-aws <[email protected]> Co-authored-by: Fanit Kolchina <[email protected]> Co-authored-by: kolchfa-aws <[email protected]> Co-authored-by: Nathan Bower <[email protected]> (cherry picked from commit deac802) Signed-off-by: github-actions[bot] <github-actions[bot]@users.noreply.github.com>
opensearch-project · Dec 2, 2024 · c7977a9 · c7977a9
1 parent d812a72
commit c7977a9
Show file tree

Hide file tree

Showing 2 changed files with 94 additions and 1 deletion.
diff --git a/_analyzers/token-filters/index.md b/_analyzers/token-filters/index.md
@@ -59,7 +59,7 @@ Token filter | Underlying Lucene token filter|  Description
 `stop` | [StopFilter](https://lucene.apache.org/core/8_7_0/core/org/apache/lucene/analysis/StopFilter.html) | Removes stop words from a token stream.
 [`synonym`]({{site.url}}{{site.baseurl}}/analyzers/token-filters/synonym/) | N/A | Supplies a synonym list for the analysis process. The synonym list is provided using a configuration file.
 [`synonym_graph`]({{site.url}}{{site.baseurl}}/analyzers/token-filters/synonym-graph/) | N/A | Supplies a synonym list, including multiword synonyms, for the analysis process.
-`trim` | [TrimFilter](https://lucene.apache.org/core/9_10_0/analysis/common/org/apache/lucene/analysis/miscellaneous/TrimFilter.html) | Trims leading and trailing white space from each token in a stream. 
+[`trim`]({{site.url}}{{site.baseurl}}/analyzers/token-filters/trim/) | [TrimFilter](https://lucene.apache.org/core/9_10_0/analysis/common/org/apache/lucene/analysis/miscellaneous/TrimFilter.html) | Trims leading and trailing white space characters from each token in a stream. 
 `truncate` | [TruncateTokenFilter](https://lucene.apache.org/core/9_10_0/analysis/common/org/apache/lucene/analysis/miscellaneous/TruncateTokenFilter.html) | Truncates tokens whose length exceeds the specified character limit. 
 `unique` | N/A | Ensures each token is unique by removing duplicate tokens from a stream. 
 `uppercase` | [UpperCaseFilter](https://lucene.apache.org/core/9_10_0/analysis/common/org/apache/lucene/analysis/core/LowerCaseFilter.html) | Converts tokens to uppercase. 

diff --git a/_analyzers/token-filters/trim.md b/_analyzers/token-filters/trim.md
@@ -0,0 +1,93 @@
+---
+layout: default
+title: Trim
+parent: Token filters
+nav_order: 430
+---
+
+# Trim token filter
+
+The `trim` token filter removes leading and trailing white space characters from tokens. 
+
+Many popular tokenizers, such as `standard`, `keyword`, and `whitespace` tokenizers, automatically strip leading and trailing white space characters during tokenization. When using these tokenizers, there is no need to configure an additional `trim` token filter. 
+{: .note}
+
+
+## Example
+
+The following example request creates a new index named `my_pattern_trim_index` and configures an analyzer with a `trim` filter and a `pattern` tokenizer, which does not remove leading and trailing white space characters:
+
+```json
+PUT /my_pattern_trim_index
+{
+  "settings": {
+    "analysis": {
+      "filter": {
+        "my_trim_filter": {
+          "type": "trim"
+        }
+      },
+      "tokenizer": {
+        "my_pattern_tokenizer": {
+          "type": "pattern",
+          "pattern": ","
+        }
+      },
+      "analyzer": {
+        "my_pattern_trim_analyzer": {
+          "type": "custom",
+          "tokenizer": "my_pattern_tokenizer",
+          "filter": [
+            "lowercase",
+            "my_trim_filter"
+          ]
+        }
+      }
+    }
+  }
+}
+```
+{% include copy-curl.html %}
+
+## Generated tokens
+
+Use the following request to examine the tokens generated using the analyzer:
+
+```json
+GET /my_pattern_trim_index/_analyze
+{
+  "analyzer": "my_pattern_trim_analyzer",
+  "text": " OpenSearch ,  is ,   powerful  "
+}
+```
+{% include copy-curl.html %}
+
+The response contains the generated tokens:
+
+```json
+{
+  "tokens": [
+    {
+      "token": "opensearch",
+      "start_offset": 0,
+      "end_offset": 12,
+      "type": "word",
+      "position": 0
+    },
+    {
+      "token": "is",
+      "start_offset": 13,
+      "end_offset": 18,
+      "type": "word",
+      "position": 1
+    },
+    {
+      "token": "powerful",
+      "start_offset": 19,
+      "end_offset": 32,
+      "type": "word",
+      "position": 2
+    }
+  ]
+}
+```