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README.md
Japanese (kuromoji) Analysis for Elasticsearch
The Japanese (kuromoji) Analysis plugin integrates Lucene kuromoji analysis module into elasticsearch.
In order to install the plugin, run:
bin/plugin install elasticsearch/elasticsearch-analysis-kuromoji/2.4.2
You need to install a version matching your Elasticsearch version:
elasticsearch | Kuromoji Analysis Plugin | Docs |
---|---|---|
master | Build from source | See below |
es-1.x | Build from source | 2.5.0-SNAPSHOT |
es-1.4 | 2.4.2 | 2.4.2 |
es-1.3 | 2.3.0 | 2.3.0 |
es-1.2 | 2.2.0 | 2.2.0 |
es-1.1 | 2.1.0 | 2.1.0 |
es-1.0 | 2.0.0 | 2.0.0 |
es-0.90 | 1.8.0 | 1.8.0 |
To build a SNAPSHOT
version, you need to build it with Maven:
mvn clean install
plugin --install analysis-kuromoji \
--url file:target/releases/elasticsearch-analysis-kuromoji-X.X.X-SNAPSHOT.zip
Includes Analyzer, Tokenizer, TokenFilter, CharFilter
The plugin includes these analyzer and tokenizer, tokenfilter.
name | type |
---|---|
kuromoji_iteration_mark | charfilter |
kuromoji | analyzer |
kuromoji_tokenizer | tokenizer |
kuromoji_baseform | tokenfilter |
kuromoji_part_of_speech | tokenfilter |
kuromoji_readingform | tokenfilter |
kuromoji_stemmer | tokenfilter |
Usage
Analyzer : kuromoji
An analyzer of type kuromoji
.
This analyzer is the following tokenizer and tokenfilter combination.
kuromoji_tokenizer
: Kuromoji Tokenizerkuromoji_baseform
: Kuromoji BasicFormFilter (TokenFilter)kuromoji_part_of_speech
: Kuromoji Part of Speech Stop Filter (TokenFilter)cjk_width
: CJK Width Filter (TokenFilter)stop
: Stop Filter (TokenFilter)kuromoji_stemmer
: Kuromoji Katakana Stemmer Filter(TokenFilter)lowercase
: LowerCase Filter (TokenFilter)
CharFilter : kuromoji_iteration_mark
A charfilter of type kuromoji_iteration_mark
.
This charfilter is Normalizes Japanese horizontal iteration marks (odoriji) to their expanded form.
The following ar setting that can be set for a kuromoji_iteration_mark
charfilter type:
Setting | Description | Default value |
---|---|---|
normalize_kanji | indicates whether kanji iteration marks should be normalized | true |
normalize_kana | indicates whether kanji iteration marks should be normalized | true |
Tokenizer : kuromoji_tokenizer
A tokenizer of type kuromoji_tokenizer
.
The following are settings that can be set for a kuromoji_tokenizer
tokenizer type:
Setting | Description | Default value |
---|---|---|
mode | Tokenization mode: this determines how the tokenizer handles compound and unknown words. normal and search , extended |
search |
discard_punctuation | true if punctuation tokens should be dropped from the output. |
true |
user_dict | set User Dictionary file |
Tokenization mode
The mode is three types.
-
normal
: Ordinary segmentation: no decomposition for compounds -
search
: Segmentation geared towards search: this includes a decompounding process for long nouns, also including the full compound token as a synonym. -
extended
: Extended mode outputs unigrams for unknown words.
Difference tokenization mode outputs
Input text is 関西国際空港
and アブラカダブラ
.
mode | 関西国際空港 |
アブラカダブラ |
---|---|---|
normal |
関西国際空港 |
アブラカダブラ |
search |
関西 関西国際空港 国際 空港 |
アブラカダブラ |
extended |
関西 国際 空港 |
ア ブ ラ カ ダ ブ ラ |
User Dictionary
Kuromoji tokenizer use MeCab-IPADIC dictionary by default. And Kuromoji is added an entry of dictionary to define by user; this is User Dictionary. User Dictionary entries are defined using the following CSV format:
<text>,<token 1> ... <token n>,<reading 1> ... <reading n>,<part-of-speech tag>
Dictionary Example
東京スカイツリー,東京 スカイツリー,トウキョウ スカイツリー,カスタム名詞
To use User Dictionary set file path to user_dict
attribute.
User Dictionary file is placed ES_HOME/config
directory.
example
Example Settings:
curl -XPUT 'http://localhost:9200/kuromoji_sample/' -d'
{
"settings": {
"index":{
"analysis":{
"tokenizer" : {
"kuromoji_user_dict" : {
"type" : "kuromoji_tokenizer",
"mode" : "extended",
"discard_punctuation" : "false",
"user_dictionary" : "userdict_ja.txt"
}
},
"analyzer" : {
"my_analyzer" : {
"type" : "custom",
"tokenizer" : "kuromoji_user_dict"
}
}
}
}
}
}
'
Example Request using _analyze
API :
curl -XPOST 'http://localhost:9200/kuromoji_sample/_analyze?analyzer=my_analyzer&pretty' -d '東京スカイツリー'
Response :
{
"tokens" : [ {
"token" : "東京",
"start_offset" : 0,
"end_offset" : 2,
"type" : "word",
"position" : 1
}, {
"token" : "スカイツリー",
"start_offset" : 2,
"end_offset" : 8,
"type" : "word",
"position" : 2
} ]
}
TokenFilter : kuromoji_baseform
A token filter of type kuromoji_baseform
that replaces term text with BaseFormAttribute.
This acts as a lemmatizer for verbs and adjectives.
example
Example Settings:
curl -XPUT 'http://localhost:9200/kuromoji_sample/' -d'
{
"settings": {
"index":{
"analysis":{
"analyzer" : {
"my_analyzer" : {
"tokenizer" : "kuromoji_tokenizer",
"filter" : ["kuromoji_baseform"]
}
}
}
}
}
}
'
Example Request using _analyze
API :
curl -XPOST 'http://localhost:9200/kuromoji_sample/_analyze?analyzer=my_analyzer&pretty' -d '飲み'
Response :
{
"tokens" : [ {
"token" : "飲む",
"start_offset" : 0,
"end_offset" : 2,
"type" : "word",
"position" : 1
} ]
}
TokenFilter : kuromoji_part_of_speech
A token filter of type kuromoji_part_of_speech
that removes tokens that match a set of part-of-speech tags.
The following are settings that can be set for a stop token filter type:
Setting | Description |
---|---|
stoptags | A list of part-of-speech tags that should be removed |
Note that default setting is stoptags.txt include lucene-analyzer-kuromoji.jar.
example
Example Settings:
curl -XPUT 'http://localhost:9200/kuromoji_sample/' -d'
{
"settings": {
"index":{
"analysis":{
"analyzer" : {
"my_analyzer" : {
"tokenizer" : "kuromoji_tokenizer",
"filter" : ["my_posfilter"]
}
},
"filter" : {
"my_posfilter" : {
"type" : "kuromoji_part_of_speech",
"stoptags" : [
"助詞-格助詞-一般",
"助詞-終助詞"
]
}
}
}
}
}
}
'
Example Request using _analyze
API :
curl -XPOST 'http://localhost:9200/kuromoji_sample/_analyze?analyzer=my_analyzer&pretty' -d '寿司がおいしいね'
Response :
{
"tokens" : [ {
"token" : "寿司",
"start_offset" : 0,
"end_offset" : 2,
"type" : "word",
"position" : 1
}, {
"token" : "おいしい",
"start_offset" : 3,
"end_offset" : 7,
"type" : "word",
"position" : 3
} ]
}
TokenFilter : kuromoji_readingform
A token filter of type kuromoji_readingform
that replaces the term attribute with the reading of a token in either katakana or romaji form.
The default reading form is katakana.
The following are settings that can be set for a kuromoji_readingform
token filter type:
Setting | Description | Default value |
---|---|---|
use_romaji | true if romaji reading form output instead of katakana. |
false |
Note that elasticsearch-analysis-kuromoji built-in kuromoji_readingform
set default true
to use_romaji
attribute.
example
Example Settings:
curl -XPUT 'http://localhost:9200/kuromoji_sample/' -d'
{
"settings": {
"index":{
"analysis":{
"analyzer" : {
"romaji_analyzer" : {
"tokenizer" : "kuromoji_tokenizer",
"filter" : ["romaji_readingform"]
},
"katakana_analyzer" : {
"tokenizer" : "kuromoji_tokenizer",
"filter" : ["katakana_readingform"]
}
},
"filter" : {
"romaji_readingform" : {
"type" : "kuromoji_readingform",
"use_romaji" : true
},
"katakana_readingform" : {
"type" : "kuromoji_readingform",
"use_romaji" : false
}
}
}
}
}
}
'
Example Request using _analyze
API :
curl -XPOST 'http://localhost:9200/kuromoji_sample/_analyze?analyzer=katakana_analyzer&pretty' -d '寿司'
Response :
{
"tokens" : [ {
"token" : "スシ",
"start_offset" : 0,
"end_offset" : 2,
"type" : "word",
"position" : 1
} ]
}
Example Request using _analyze
API :
curl -XPOST 'http://localhost:9200/kuromoji_sample/_analyze?analyzer=romaji_analyzer&pretty' -d '寿司'
Response :
{
"tokens" : [ {
"token" : "sushi",
"start_offset" : 0,
"end_offset" : 2,
"type" : "word",
"position" : 1
} ]
}
TokenFilter : kuromoji_stemmer
A token filter of type kuromoji_stemmer
that normalizes common katakana spelling variations ending in a long sound character by removing this character (U+30FC).
Only katakana words longer than a minimum length are stemmed (default is four).
Note that only full-width katakana characters are supported.
The following are settings that can be set for a kuromoji_stemmer
token filter type:
Setting | Description | Default value |
---|---|---|
minimum_length | The minimum length to stem | 4 |
example
Example Settings:
curl -XPUT 'http://localhost:9200/kuromoji_sample/' -d'
{
"settings": {
"index":{
"analysis":{
"analyzer" : {
"my_analyzer" : {
"tokenizer" : "kuromoji_tokenizer",
"filter" : ["my_katakana_stemmer"]
}
},
"filter" : {
"my_katakana_stemmer" : {
"type" : "kuromoji_stemmer",
"minimum_length" : 4
}
}
}
}
}
}
'
Example Request using _analyze
API :
curl -XPOST 'http://localhost:9200/kuromoji_sample/_analyze?analyzer=my_analyzer&pretty' -d 'コピー'
Response :
{
"tokens" : [ {
"token" : "コピー",
"start_offset" : 0,
"end_offset" : 3,
"type" : "word",
"position" : 1
} ]
}
Example Request using _analyze
API :
curl -XPOST 'http://localhost:9200/kuromoji_sample/_analyze?analyzer=my_analyzer&pretty' -d 'サーバー'
Response :
{
"tokens" : [ {
"token" : "サーバ",
"start_offset" : 0,
"end_offset" : 4,
"type" : "word",
"position" : 1
} ]
}
License
This software is licensed under the Apache 2 license, quoted below.
Copyright 2009-2014 Elasticsearch <http://www.elasticsearch.org>
Licensed under the Apache License, Version 2.0 (the "License"); you may not
use this file except in compliance with the License. You may obtain a copy of
the License at
http://www.apache.org/licenses/LICENSE-2.0
Unless required by applicable law or agreed to in writing, software
distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
License for the specific language governing permissions and limitations under
the License.