192 lines
8.0 KiB
Markdown
192 lines
8.0 KiB
Markdown
ICU Analysis for Elasticsearch
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==================================
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The ICU Analysis plugin integrates Lucene ICU module into elasticsearch, adding ICU relates analysis components.
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In order to install the plugin, simply run: `bin/plugin -install elasticsearch/elasticsearch-analysis-icu/1.13.0`.
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| ICU Analysis Plugin | elasticsearch | Release date |
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| 1.14.0-SNAPSHOT (master) | 0.90.8 -> 0.90 | |
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| 1.13.0 | 0.90.8 -> 0.90 | 2013-12-19 |
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| 1.12.0 | 0.90.6 -> 0.90.7 | 2013-11-06 |
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| 1.11.0 | 0.90.3 -> 0.90.5 | 2013-08-08 |
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| 1.10.0 | 0.90.1 -> 0.90.2 | 2013-05-30 |
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| 1.9.0 | 0.90.0 | 2013-04-29 |
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| 1.8.0 | 0.90.0 | 2013-02-26 |
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| 1.7.0 | 0.19 -> 0.20 | 2012-09-28 |
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| 1.6.0 | 0.19 -> 0.20 | 2012-09-27 |
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| 1.5.0 | 0.19 -> 0.20 | 2012-04-30 |
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| 1.4.0 | 0.19 -> 0.20 | 2012-03-20 |
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| 1.3.0 | 0.19 -> 0.20 | 2012-03-20 |
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| 1.2.0 | 0.19 -> 0.20 | 2012-02-07 |
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| 1.1.0 | 0.18 | 2011-12-13 |
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| 1.0.0 | 0.18 | 2011-12-05 |
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ICU Normalization
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-----------------
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Normalizes characters as explained "here":http://userguide.icu-project.org/transforms/normalization. It registers itself by default under `icu_normalizer` or `icuNormalizer` using the default settings. Allows for the name parameter to be provided which can include the following values: `nfc`, `nfkc`, and `nfkc_cf`. Here is a sample settings:
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{
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"index" : {
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"analysis" : {
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"analyzer" : {
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"collation" : {
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"tokenizer" : "keyword",
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"filter" : ["icu_normalizer"]
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}
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}
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}
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}
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}
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ICU Folding
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-----------
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Folding of unicode characters based on `UTR#30`. It registers itself under `icu_folding` and `icuFolding` names. Sample setting:
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{
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"index" : {
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"analysis" : {
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"analyzer" : {
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"collation" : {
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"tokenizer" : "keyword",
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"filter" : ["icu_folding"]
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}
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}
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}
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}
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}
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ICU Filtering
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-------------
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The folding can be filtered by a set of unicode characters with the parameter `unicodeSetFilter`. This is useful for a non-internationalized search engine where retaining a set of national characters which are primary letters in a specific language is wanted. See syntax for the UnicodeSet "here":http://icu-project.org/apiref/icu4j/com/ibm/icu/text/UnicodeSet.html.
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The Following example exempts Swedish characters from the folding. Note that the filtered characters are NOT lowercased which is why we add that filter below.
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{
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"index" : {
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"analysis" : {
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"analyzer" : {
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"folding" : {
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"tokenizer" : "standard",
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"filter" : ["my_icu_folding", "lowercase"]
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}
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}
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"filter" : {
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"my_icu_folding" : {
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"type" : "icu_folding"
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"unicodeSetFilter" : "[^åäöÅÄÖ]"
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}
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}
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}
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}
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}
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ICU Collation
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-------------
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Uses collation token filter. Allows to either specify the rules for collation (defined "here":http://www.icu-project.org/userguide/Collate_Customization.html) using the `rules` parameter (can point to a location or expressed in the settings, location can be relative to config location), or using the `language` parameter (further specialized by country and variant). By default registers under `icu_collation` or `icuCollation` and uses the default locale.
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Here is a sample settings:
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{
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"index" : {
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"analysis" : {
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"analyzer" : {
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"collation" : {
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"tokenizer" : "keyword",
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"filter" : ["icu_collation"]
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}
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}
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}
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}
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}
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And here is a sample of custom collation:
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{
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"index" : {
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"analysis" : {
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"analyzer" : {
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"collation" : {
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"tokenizer" : "keyword",
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"filter" : ["myCollator"]
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}
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},
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"filter" : {
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"myCollator" : {
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"type" : "icu_collation",
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"language" : "en"
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}
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}
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}
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}
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}
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Optional options:
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* `strength` - The strength property determines the minimum level of difference considered significant during comparison.
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The default strength for the Collator is `tertiary`, unless specified otherwise by the locale used to create the Collator.
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Possible values: `primary`, `secondary`, `tertiary`, `quaternary` or `identical`.
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See ICU Collation:http://icu-project.org/apiref/icu4j/com/ibm/icu/text/Collator.html documentation for a more detailed
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explanation for the specific values.
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* `decomposition` - Possible values: `no` or `canonical`. Defaults to `no`. Setting this decomposition property with
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`canonical` allows the Collator to handle un-normalized text properly, producing the same results as if the text were
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normalized. If `no` is set, it is the user's responsibility to insure that all text is already in the appropriate form
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before a comparison or before getting a CollationKey. Adjusting decomposition mode allows the user to select between
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faster and more complete collation behavior. Since a great many of the world's languages do not require text
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normalization, most locales set `no` as the default decomposition mode.
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Expert options:
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* `alternate` - Possible values: `shifted` or `non-ignorable`. Sets the alternate handling for strength `quaternary`
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to be either shifted or non-ignorable. What boils down to ignoring punctuation and whitespace.
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* `caseLevel` - Possible values: `true` or `false`. Default is `false`. Whether case level sorting is required. When
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strength is set to `primary` this will ignore accent differences.
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* `caseFirst` - Possible values: `lower` or `upper`. Useful to control which case is sorted first when case is not ignored
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for strength `tertiary`.
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* `numeric` - Possible values: `true` or `false`. Whether digits are sorted according to numeric representation. For
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example the value `egg-9` is sorted before the value `egg-21`. Defaults to `false`.
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* `variableTop` - Single character or contraction. Controls what is variable for `alternate`.
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* `hiraganaQuaternaryMode` - Possible values: `true` or `false`. Defaults to `false`. Distinguishing between Katakana
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and Hiragana characters in `quaternary` strength .
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ICU Tokenizer
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-------------
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Breaks text into words according to UAX #29: Unicode Text Segmentation ((http://www.unicode.org/reports/tr29/)).
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{
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"index" : {
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"analysis" : {
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"analyzer" : {
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"collation" : {
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"tokenizer" : "icu_tokenizer",
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}
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}
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}
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}
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}
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License
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-------
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This software is licensed under the Apache 2 license, quoted below.
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Copyright 2009-2014 Elasticsearch <http://www.elasticsearch.org>
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Licensed under the Apache License, Version 2.0 (the "License"); you may not
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use this file except in compliance with the License. You may obtain a copy of
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the License at
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http://www.apache.org/licenses/LICENSE-2.0
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Unless required by applicable law or agreed to in writing, software
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distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
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WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
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License for the specific language governing permissions and limitations under
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the License.
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