Hyphenation decompounder token filteredit
Uses XML-based hyphenation patterns to find potential subwords in compound words. These subwords are then checked against the specified word list. Subwords not in the list are excluded from the token output.
This filter uses Lucene’s HyphenationCompoundWordTokenFilter, which was built for Germanic languages.
Exampleedit
The following analyze API request uses the
hyphenation_decompounder filter to find subwords in Kaffeetasse based on
German hyphenation patterns in the analysis/hyphenation_patterns.xml file. The
filter then checks these subwords against a list of specified words: kaffee,
zucker, and tasse.
GET _analyze
{
"tokenizer": "standard",
"filter": [
{
"type": "hyphenation_decompounder",
"hyphenation_patterns_path": "analysis/hyphenation_patterns.xml",
"word_list": ["Kaffee", "zucker", "tasse"]
}
],
"text": "Kaffeetasse"
}
The filter produces the following tokens:
[ Kaffeetasse, Kaffee, tasse ]
Configurable parametersedit
-
hyphenation_patterns_path -
(Required, string) Path to an Apache FOP (Formatting Objects Processor) XML hyphenation pattern file.
This path must be absolute or relative to the
configlocation. Only FOP v1.2 compatible files are supported.For example FOP XML hyphenation pattern files, refer to:
-
word_list -
(Required*, array of strings) A list of subwords. Subwords found using the hyphenation pattern but not in this list are excluded from the token output.
You can use the
dictionary_decompounderfilter to test the quality of word lists before implementing them.Either this parameter or
word_list_pathmust be specified. -
word_list_path -
(Required*, string) Path to a file containing a list of subwords. Subwords found using the hyphenation pattern but not in this list are excluded from the token output.
This path must be absolute or relative to the
configlocation, and the file must be UTF-8 encoded. Each token in the file must be separated by a line break.You can use the
dictionary_decompounderfilter to test the quality of word lists before implementing them.Either this parameter or
word_listmust be specified. -
max_subword_size -
(Optional, integer)
Maximum subword character length. Longer subword tokens are excluded from the
output. Defaults to
15. -
min_subword_size -
(Optional, integer)
Minimum subword character length. Shorter subword tokens are excluded from the
output. Defaults to
2. -
min_word_size -
(Optional, integer)
Minimum word character length. Shorter word tokens are excluded from the
output. Defaults to
5. -
only_longest_match -
(Optional, boolean)
If
true, only include the longest matching subword. Defaults tofalse.
Customize and add to an analyzeredit
To customize the hyphenation_decompounder filter, duplicate it to create the
basis for a new custom token filter. You can modify the filter using its
configurable parameters.
For example, the following create index API request
uses a custom hyphenation_decompounder filter to configure a new
custom analyzer.
The custom hyphenation_decompounder filter find subwords based on hyphenation
patterns in the analysis/hyphenation_patterns.xml file. The filter then checks
these subwords against the list of words specified in the
analysis/example_word_list.txt file. Subwords longer than 22 characters are
excluded from the token output.
PUT hyphenation_decompound_example
{
"settings": {
"analysis": {
"analyzer": {
"standard_hyphenation_decompound": {
"tokenizer": "standard",
"filter": [ "22_char_hyphenation_decompound" ]
}
},
"filter": {
"22_char_hyphenation_decompound": {
"type": "hyphenation_decompounder",
"word_list_path": "analysis/example_word_list.txt",
"hyphenation_patterns_path": "analysis/hyphenation_patterns.xml",
"max_subword_size": 22
}
}
}
}
}