[
https://issues.apache.org/jira/browse/LUCENE-7701?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel
]
Alan Woodward updated LUCENE-7701:
----------------------------------
Attachment: LUCENE-7701.patch
This patch also refactors the second-pass collector into a concrete class that
accepts a GroupReducer. GroupReducers return a Collector instance for each
group that is to be reduced, so for example the TopGroupsCollector will create
a TopDocsCollector for each group.
Now if you want to create a new type of group (a set of ranges over a
DoubleValuesSource, for example) you just need to create a GroupSelector
implementation; and if you want to create a new type of group summarizer (say
some statistics over a group), then you create a GroupReducer implementation.
There's a failing test in Solr that I still need to track down, but I think
this is a much nicer grouping interface. It is not at all backwards
compatible, so I'd be targeting this at 7.0. cc [~martijn.v.groningen]
> Refactor grouping collectors
> ----------------------------
>
> Key: LUCENE-7701
> URL: https://issues.apache.org/jira/browse/LUCENE-7701
> Project: Lucene - Core
> Issue Type: Improvement
> Reporter: Alan Woodward
> Attachments: LUCENE-7701.patch, LUCENE-7701.patch
>
>
> Grouping currently works via abstract collectors, which need to be overridden
> for each way of defining a group - currently we have two, 'term' (based on
> SortedDocValues) and 'function' (based on ValueSources). These collectors
> all have a lot of repeated code, and means that if you want to implement your
> own group definitions, you need to override four or five different classes.
> This would be easier to deal with if instead the 'group selection' code was
> abstracted out into a single interface, and the various collectors were
> changed to concrete implementations.
--
This message was sent by Atlassian JIRA
(v6.3.15#6346)
---------------------------------------------------------------------
To unsubscribe, e-mail: dev-unsubscr...@lucene.apache.org
For additional commands, e-mail: dev-h...@lucene.apache.org
