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https://issues.apache.org/jira/browse/LUCENE-6459?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel
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Areek Zillur updated LUCENE-6459:
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Attachment: LUCENE-6459.patch
> [suggest] Query Interface for suggest API
> -----------------------------------------
>
> Key: LUCENE-6459
> URL: https://issues.apache.org/jira/browse/LUCENE-6459
> Project: Lucene - Core
> Issue Type: New Feature
> Components: core/search
> Affects Versions: 5.1
> Reporter: Areek Zillur
> Assignee: Areek Zillur
> Fix For: Trunk, 5.x, 5.1
>
> Attachments: LUCENE-6459.patch, LUCENE-6459.patch, LUCENE-6459.patch,
> LUCENE-6459.patch, LUCENE-6459.patch, LUCENE-6459.patch, LUCENE-6459.patch
>
>
> This patch factors out common indexing/search API used by the recently
> introduced [NRTSuggester|https://issues.apache.org/jira/browse/LUCENE-6339].
> The motivation is to provide a query interface for FST-based fields
> (*SuggestField* and *ContextSuggestField*)
> for enabling suggestion scoring and more powerful automaton queries.
> Previously, only prefix ‘queries’ with index-time weights were supported but
> we can also support:
> * Prefix queries expressed as regular expressions: get suggestions that
> match multiple prefixes
> ** *Example:* _star\[wa\|tr\]_ matches _starwars_ and _startrek_
> * Fuzzy Prefix queries supporting scoring: get typo tolerant suggestions
> scored by how close they are to the query prefix
> ** *Example:* querying for _seper_ will score _separate_ higher then
> _superstitious_
> * Context Queries: get suggestions boosted and/or filtered based on their
> indexed contexts (meta data)
> ** *Boost example:* get typo tolerant suggestions on song names with
> prefix _like a roling_ boosting songs with
> genre _rock_ and _indie_
> ** *Filter example:* get suggestion on all file names starting with
> _finan_ only for _user1_ and _user2_
> h3. Suggest API
> {code}
> SuggestIndexSearcher searcher = new SuggestIndexSearcher(reader);
> CompletionQuery query = ...
> TopSuggestDocs suggest = searcher.suggest(query, num);
> {code}
> h3. CompletionQuery
> *CompletionQuery* is used to query *SuggestField* and *ContextSuggestField*.
> A *CompletionQuery* produces a *CompletionWeight*,
> which allows *CompletionQuery* implementations to pass in an automaton that
> will be intersected with a FST and allows boosting and
> meta data extraction from the intersected partial paths. A *CompletionWeight*
> produces a *CompletionScorer*. A *CompletionScorer*
> executes a Top N search against the FST with the provided automaton, scoring
> and filtering all matched paths.
> h4. PrefixCompletionQuery
> Return documents with values that match the prefix of an analyzed term text
> Documents are sorted according to their suggest field weight.
> {code}
> PrefixCompletionQuery(Analyzer analyzer, Term term)
> {code}
> h4. RegexCompletionQuery
> Return documents with values that match the prefix of a regular expression
> Documents are sorted according to their suggest field weight.
> {code}
> RegexCompletionQuery(Term term)
> {code}
> h4. FuzzyCompletionQuery
> Return documents with values that has prefixes within a specified edit
> distance of an analyzed term text.
> Documents are ‘boosted’ by the number of matching prefix letters of the
> suggestion with respect to the original term text.
> {code}
> FuzzyCompletionQuery(Analyzer analyzer, Term term)
> {code}
> h5. Scoring
> {{suggestion_weight + (global_maximum_weight * boost)}}
> where {{suggestion_weight}}, {{global_maximum_weight}} and {{boost}} are all
> integers.
> {{boost = # of prefix characters matched}}
> h4. ContextQuery
> Return documents that match a {{CompletionQuery}} filtered and/or boosted by
> provided context(s).
> {code}
> ContextQuery(CompletionQuery query)
> contextQuery.addContext(CharSequence context, int boost, boolean exact)
> {code}
> *NOTE:* {{ContextQuery}} should be used with {{ContextSuggestField}} to query
> suggestions boosted and/or filtered by contexts.
> Running {{ContextQuery}} against a {{SuggestField}} will error out.
> h5. Scoring
> {{suggestion_weight + (global_maximum_weight * context_boost)}}
> where {{suggestion_weight}}, {{global_maximum_weight}} and {{context_boost}}
> are all integers
> When used with {{FuzzyCompletionQuery}},
> {{suggestion_weight + (global_maximum_weight * (context_boost +
> fuzzy_boost))}}
> h3. Context Suggest Field
> To use {{ContextQuery}}, use {{ContextSuggestField}} instead of
> {{SuggestField}}. Any {{CompletionQuery}} can be used with
> {{ContextSuggestField}}, the default behaviour is to return suggestions from
> *all* contexts. {{Context}} for every completion hit
> can be accessed through {{SuggestScoreDoc#context}}.
> {code}
> ContextSuggestField(String name, Collection<CharSequence> contexts, String
> value, int weight)
> {code}
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