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From "Uwe Schindler (JIRA)" <j...@apache.org>
Subject [jira] [Commented] (LUCENE-8186) CustomAnalyzer with a LowerCaseTokenizerFactory fails to normalize multiterms
Date Tue, 27 Feb 2018 13:58:00 GMT

    [ https://issues.apache.org/jira/browse/LUCENE-8186?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=16378612#comment-16378612
] 

Uwe Schindler commented on LUCENE-8186:
---------------------------------------

I think the main problem is that "normalizing" is defined to only apply all the tokenfilters
on a single term, not doing tokenization!

The problem in your example is LowercaseTokenizer, which does 2 things at same time. IMHO,
LowercaseTokenizer should be deprecated and removed. It is always always replaceable by using
the LetterTokenizer with LowercaseFilter. There should be no performance difference anymore,
as both do the same, it's just an additional method call and the loop is executed twice instead
of once. But the expensive work is the same.

> CustomAnalyzer with a LowerCaseTokenizerFactory fails to normalize multiterms 
> ------------------------------------------------------------------------------
>
>                 Key: LUCENE-8186
>                 URL: https://issues.apache.org/jira/browse/LUCENE-8186
>             Project: Lucene - Core
>          Issue Type: Bug
>            Reporter: Tim Allison
>            Priority: Minor
>
> While working on SOLR-12034, a unit test that relied on the LowerCaseTokenizerFactory
failed.
> After some digging, I was able to replicate this at the Lucene level.
> Unit test:
> {noformat}
>   @Test
>   public void testLCTokenizerFactoryNormalize() throws Exception {
>     Analyzer analyzer =  CustomAnalyzer.builder().withTokenizer(LowerCaseTokenizerFactory.class).build();
>     //fails
>     assertEquals(new BytesRef("hello"), analyzer.normalize("f", "Hello"));
>     
>     //now try an integration test with the classic query parser
>     QueryParser p = new QueryParser("f", analyzer);
>     Query q = p.parse("Hello");
>     //passes
>     assertEquals(new TermQuery(new Term("f", "hello")), q);
>     q = p.parse("Hello*");
>     //fails
>     assertEquals(new PrefixQuery(new Term("f", "hello")), q);
>     q = p.parse("Hel*o");
>     //fails
>     assertEquals(new WildcardQuery(new Term("f", "hel*o")), q);
>   }
> {noformat}
> The problem is that the CustomAnalyzer iterates through the tokenfilters, but does not
call the tokenizer, which, in the case of the LowerCaseTokenizer, does the filtering work.



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