Adding Collation Key Analyzer

[jprante]

Hi,

this patch adds the Lucene CollationKeyAnalyzer for locale-sensitive sorting by using java.text.Collator. I know that ICUCollationKey is much preferable https://issues.apache.org/jira/browse/LUCENE-1719 but it could be useful for non-ICU environments, and where performance is not very important. See also my pull request for java.text.Collator based terms facet sorting. It would be nice being able to align hit sorting and terms facet sorting.

Test is included for demonstrating a collation-key based sort.

Cheers, Jörg

[clintongormley]

Closing in favour of #6917

[GeetNair]

I am new to elasticsearch and I would like to know the steps required to use the ICU plugin as a library i.e. we call some API in that plugin which converts our field into required format for sorting.

the problem is that we are trying to use the doc_values = true option in mapping but this cannot be used for string fields having analyzer.So if we need to use ICU plugin then we cannot use doc_value option.

Also will you please provide me stepwise guid from how to install and what needs to be done

[jprante]

@GeetNair this pull request was about aggregations with (non-ICU) collation-based sort. Your question is about the ICU plugin. Please open an issue there.