[LUCENE-9088] JapaneseNumberFilter uses inaccurate PartOfSpeechAttribute

• Type: Bug
• Status: Open
• Priority: Major
• Resolution: Unresolved
• Component/s: modules/analysis
• Lucene Fields: New
• Assignee: Unassigned
• Reporter: Christoph Büscher
• Created: 10/Dec/19 12:44
• Updated: 28/Aug/22 15:54

Description

According to the JapaneseNumberFilter javadocs, it uses the attribute values of the last token used to compose the normalized number, which can be wrong. While this is documented it leads to a number of incompatibilities with other japanese token filters.

For example, the PartOfSpeechAttribute of the last token used for an input text of "2008 2009" will lead to an the following output (some attributes left out...):

```

{ "token" : "2008", "start_offset" : 0, "end_offset" : 4, "type" : "word", [...] "partOfSpeech" : "記号-空白", "partOfSpeech (en)" : "symbol-space" [...] }

,

{ "token" : " ", "start_offset" : 4, "end_offset" : 5, "type" : "word", [...] "partOfSpeech" : "記号-空白", "partOfSpeech (en)" : "symbol-space", [...] }

,

{ "token" : "2009", "start_offset" : 5, "end_offset" : 9, "type" : "word", ... "partOfSpeech" : "名詞-数", "partOfSpeech (en)" : "noun-numeric", }

```

so that e.g. a following `kuromoji_part_of_speech` filter will eliminate the "2008" token erroneously tagged as "symbol-space".

Even without fixing the other token attrobutes, the POS attributes should IMHO be set to "noun-numeric", since that's what the filter is supposed to detect.

Issue Links

• links to: GitHub Pull Request #1073