Package org.apache.lucene.search
Class QueryVisitor
- java.lang.Object
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- org.apache.lucene.search.QueryVisitor
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public abstract class QueryVisitor extends Object
Allows recursion through a query tree- See Also:
Query.visit(QueryVisitor)
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Field Summary
Fields Modifier and Type Field Description static QueryVisitorEMPTY_VISITORA QueryVisitor implementation that does nothing
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Constructor Summary
Constructors Constructor Description QueryVisitor()
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Method Summary
All Methods Static Methods Instance Methods Concrete Methods Modifier and Type Method Description booleanacceptField(String field)Whether or not this field is of interest to the visitorvoidconsumeTerms(Query query, Term... terms)Called by leaf queries that match on specific termsvoidconsumeTermsMatching(Query query, String field, Supplier<ByteRunAutomaton> automaton)Called by leaf queries that match on a class of termsQueryVisitorgetSubVisitor(BooleanClause.Occur occur, Query parent)Pulls a visitor instance for visiting child clauses of a querystatic QueryVisitortermCollector(Set<Term> termSet)Builds aQueryVisitorinstance that collects all terms that may match a queryvoidvisitLeaf(Query query)Called by leaf queries that do not match on terms
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Field Detail
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EMPTY_VISITOR
public static final QueryVisitor EMPTY_VISITOR
A QueryVisitor implementation that does nothing
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Method Detail
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consumeTerms
public void consumeTerms(Query query, Term... terms)
Called by leaf queries that match on specific terms- Parameters:
query- the leaf queryterms- the terms the query will match on
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consumeTermsMatching
public void consumeTermsMatching(Query query, String field, Supplier<ByteRunAutomaton> automaton)
Called by leaf queries that match on a class of terms- Parameters:
query- the leaf queryfield- the field queried againstautomaton- a supplier for an automaton defining which terms match- WARNING: This API is experimental and might change in incompatible ways in the next release.
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visitLeaf
public void visitLeaf(Query query)
Called by leaf queries that do not match on terms- Parameters:
query- the query
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acceptField
public boolean acceptField(String field)
Whether or not this field is of interest to the visitorImplement this to avoid collecting terms from heavy queries such as
TermInSetQuerythat are not running on fields of interest
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getSubVisitor
public QueryVisitor getSubVisitor(BooleanClause.Occur occur, Query parent)
Pulls a visitor instance for visiting child clauses of a queryThe default implementation returns
this, unlessoccuris equal toBooleanClause.Occur.MUST_NOTin which case it returnsEMPTY_VISITOR- Parameters:
occur- the relationship between the parent and its childrenparent- the query visited
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termCollector
public static QueryVisitor termCollector(Set<Term> termSet)
Builds aQueryVisitorinstance that collects all terms that may match a query- Parameters:
termSet- aSetto add collected terms to
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