Class IndexSearcher

Implements search over a single IndexReader.

Applications usually need only call the inherited Search(Query, Int32) or Search(Query, Filter, Int32) methods. For performance reasons, if your index is unchanging, you should share a single IndexSearcher instance across multiple searches instead of creating a new one per-search. If your index has changed and you wish to see the changes reflected in searching, you should use OpenIfChanged(DirectoryReader) to obtain a new reader and then create a new IndexSearcher from that. Also, for low-latency turnaround it's best to use a near-real-time reader (Open(IndexWriter, Boolean)). Once you have a new IndexReader, it's relatively cheap to create a new IndexSearcher from it.

NOTE: IndexSearcher instances are completely thread safe, meaning multiple threads can call any of its methods, concurrently. If your application requires external synchronization, you should not synchronize on the IndexSearcher instance; use your own (non-Lucene) objects instead.

Inheritance
System.Object
IndexSearcher
Inherited Members
System.Object.Equals(System.Object)
System.Object.Equals(System.Object, System.Object)
System.Object.GetHashCode()
System.Object.GetType()
System.Object.MemberwiseClone()
System.Object.ReferenceEquals(System.Object, System.Object)
Namespace: Lucene.Net.Search
Assembly: Lucene.Net.dll
Syntax
public class IndexSearcher

Constructors

| Improve this Doc View Source

IndexSearcher(IndexReader)

Creates a searcher searching the provided index.

Declaration
public IndexSearcher(IndexReader r)
Parameters
Type Name Description
IndexReader r
| Improve this Doc View Source

IndexSearcher(IndexReader, TaskScheduler)

Runs searches for each segment separately, using the provided System.Threading.Tasks.TaskScheduler. IndexSearcher will not shutdown/awaitTermination this System.Threading.Tasks.TaskScheduler on dispose; you must do so, eventually, on your own.

This is a Lucene.NET EXPERIMENTAL API, use at your own risk
Declaration
public IndexSearcher(IndexReader r, TaskScheduler executor)
Parameters
Type Name Description
IndexReader r
System.Threading.Tasks.TaskScheduler executor
| Improve this Doc View Source

IndexSearcher(IndexReaderContext)

Creates a searcher searching the provided top-level IndexReaderContext.

This is a Lucene.NET EXPERIMENTAL API, use at your own risk
Declaration
public IndexSearcher(IndexReaderContext context)
Parameters
Type Name Description
IndexReaderContext context
See Also
| Improve this Doc View Source

IndexSearcher(IndexReaderContext, TaskScheduler)

Creates a searcher searching the provided top-level IndexReaderContext.

Given a non-null System.Threading.Tasks.TaskScheduler this method runs searches for each segment separately, using the provided System.Threading.Tasks.TaskScheduler. IndexSearcher will not shutdown/awaitTermination this System.Threading.Tasks.TaskScheduler on close; you must do so, eventually, on your own.

This is a Lucene.NET EXPERIMENTAL API, use at your own risk

Declaration
public IndexSearcher(IndexReaderContext context, TaskScheduler executor)
Parameters
Type Name Description
IndexReaderContext context
System.Threading.Tasks.TaskScheduler executor
See Also

Fields

| Improve this Doc View Source

m_leafContexts

Declaration
protected readonly IList<AtomicReaderContext> m_leafContexts
Field Value
Type Description
System.Collections.Generic.IList<AtomicReaderContext>
| Improve this Doc View Source

m_leafSlices

Used with executor - each slice holds a set of leafs executed within one thread

Declaration
protected readonly IndexSearcher.LeafSlice[] m_leafSlices
Field Value
Type Description
IndexSearcher.LeafSlice[]
| Improve this Doc View Source

m_readerContext

Declaration
protected readonly IndexReaderContext m_readerContext
Field Value
Type Description
IndexReaderContext

Properties

| Improve this Doc View Source

DefaultSimilarity

Expert: returns a default Similarity instance. In general, this method is only called to initialize searchers and writers. User code and query implementations should respect Similarity.

This is a Lucene.NET INTERNAL API, use at your own risk
Declaration
public static Similarity DefaultSimilarity { get; }
Property Value
Type Description
Similarity
| Improve this Doc View Source

IndexReader

Return the IndexReader this searches.

Declaration
public virtual IndexReader IndexReader { get; }
Property Value
Type Description
IndexReader
| Improve this Doc View Source

Similarity

Expert: Set the Similarity implementation used by this IndexSearcher.

Declaration
public virtual Similarity Similarity { get; set; }
Property Value
Type Description
Similarity
| Improve this Doc View Source

TopReaderContext

Returns this searchers the top-level IndexReaderContext.

Declaration
public virtual IndexReaderContext TopReaderContext { get; }
Property Value
Type Description
IndexReaderContext
See Also

Methods

| Improve this Doc View Source

CollectionStatistics(String)

Returns CollectionStatistics for a field.

This can be overridden for example, to return a field's statistics across a distributed collection.

This is a Lucene.NET EXPERIMENTAL API, use at your own risk
Declaration
public virtual CollectionStatistics CollectionStatistics(string field)
Parameters
Type Name Description
System.String field
Returns
Type Description
CollectionStatistics
| Improve this Doc View Source

CreateNormalizedWeight(Query)

Creates a normalized weight for a top-level Query. The query is rewritten by this method and CreateWeight(IndexSearcher) called, afterwards the Weight is normalized. The returned Weight can then directly be used to get a Scorer.

This is a Lucene.NET INTERNAL API, use at your own risk
Declaration
public virtual Weight CreateNormalizedWeight(Query query)
Parameters
Type Name Description
Query query
Returns
Type Description
Weight
| Improve this Doc View Source

Doc(Int32)

Sugar for 

.IndexReader.Document(docID)

Declaration
public virtual Document Doc(int docID)
Parameters
Type Name Description
System.Int32 docID
Returns
Type Description
Document
See Also
Document(System.Int32)
| Improve this Doc View Source

Doc(Int32, StoredFieldVisitor)

Sugar for 

.IndexReader.Document(docID, fieldVisitor)

Declaration
public virtual void Doc(int docID, StoredFieldVisitor fieldVisitor)
Parameters
Type Name Description
System.Int32 docID
StoredFieldVisitor fieldVisitor
See Also
| Improve this Doc View Source

Doc(Int32, ISet<String>)

Sugar for 

.IndexReader.Document(docID, fieldsToLoad)

Declaration
public virtual Document Doc(int docID, ISet<string> fieldsToLoad)
Parameters
Type Name Description
System.Int32 docID
System.Collections.Generic.ISet<System.String> fieldsToLoad
Returns
Type Description
Document
See Also
Document(System.Int32, System.Collections.Generic.ISet<System.String>)
| Improve this Doc View Source

Document(Int32, ISet<String>)

Declaration
[Obsolete("Use <seealso cref=#doc(int, java.util.Set)/> instead.")]
public Document Document(int docID, ISet<string> fieldsToLoad)
Parameters
Type Name Description
System.Int32 docID
System.Collections.Generic.ISet<System.String> fieldsToLoad
Returns
Type Description
Document
| Improve this Doc View Source

Explain(Query, Int32)

Returns an Explanation that describes how doc scored against query.

This is intended to be used in developing Similarity implementations, and, for good performance, should not be displayed with every hit. Computing an explanation is as expensive as executing the query over the entire index.

Declaration
public virtual Explanation Explain(Query query, int doc)
Parameters
Type Name Description
Query query
System.Int32 doc
Returns
Type Description
Explanation
| Improve this Doc View Source

Explain(Weight, Int32)

Expert: low-level implementation method Returns an Explanation that describes how doc scored against weight.

This is intended to be used in developing Similarity implementations, and, for good performance, should not be displayed with every hit. Computing an explanation is as expensive as executing the query over the entire index.

Applications should call Explain(Query, Int32).

Declaration
protected virtual Explanation Explain(Weight weight, int doc)
Parameters
Type Name Description
Weight weight
System.Int32 doc
Returns
Type Description
Explanation
Exceptions
Type Condition
BooleanQuery.TooManyClausesException

If a query would exceed MaxClauseCount clauses.

| Improve this Doc View Source

Rewrite(Query)

Expert: called to re-write queries into primitive queries.

Declaration
public virtual Query Rewrite(Query original)
Parameters
Type Name Description
Query original
Returns
Type Description
Query
Exceptions
Type Condition
BooleanQuery.TooManyClausesException

If a query would exceed MaxClauseCount clauses.

| Improve this Doc View Source

Search(Query, Filter, ICollector)

Lower-level search API.

Collect(Int32) is called for every matching document.

Declaration
public virtual void Search(Query query, Filter filter, ICollector results)
Parameters
Type Name Description
Query query

To match documents

Filter filter

Ef non-null, used to permit documents to be collected.

ICollector results

To receive hits

Exceptions
Type Condition
BooleanQuery.TooManyClausesException

If a query would exceed MaxClauseCount clauses.

| Improve this Doc View Source

Search(Query, Filter, Int32)

Finds the top n hits for query, applying filter if non-null.

Declaration
public virtual TopDocs Search(Query query, Filter filter, int n)
Parameters
Type Name Description
Query query
Filter filter
System.Int32 n
Returns
Type Description
TopDocs
Exceptions
Type Condition
BooleanQuery.TooManyClausesException

If a query would exceed MaxClauseCount clauses.

| Improve this Doc View Source

Search(Query, Filter, Int32, Sort)

Search implementation with arbitrary sorting. Finds the top n hits for query, applying filter if non-null, and sorting the hits by the criteria in sort.

NOTE: this does not compute scores by default; use Search(Query, Filter, Int32, Sort, Boolean, Boolean) to control scoring.

Declaration
public virtual TopFieldDocs Search(Query query, Filter filter, int n, Sort sort)
Parameters
Type Name Description
Query query
Filter filter
System.Int32 n
Sort sort
Returns
Type Description
TopFieldDocs
Exceptions
Type Condition
BooleanQuery.TooManyClausesException

If a query would exceed MaxClauseCount clauses.

| Improve this Doc View Source

Search(Query, Filter, Int32, Sort, Boolean, Boolean)

Search implementation with arbitrary sorting, plus control over whether hit scores and max score should be computed. Finds the top n hits for query, applying filter if non-null, and sorting the hits by the criteria in sort. If doDocScores is true then the score of each hit will be computed and returned. If doMaxScore is true then the maximum score over all collected hits will be computed.

Declaration
public virtual TopFieldDocs Search(Query query, Filter filter, int n, Sort sort, bool doDocScores, bool doMaxScore)
Parameters
Type Name Description
Query query
Filter filter
System.Int32 n
Sort sort
System.Boolean doDocScores
System.Boolean doMaxScore
Returns
Type Description
TopFieldDocs
Exceptions
Type Condition
BooleanQuery.TooManyClausesException

If a query would exceed MaxClauseCount clauses.

| Improve this Doc View Source

Search(Query, ICollector)

Lower-level search API.

Collect(Int32) is called for every matching document.

Declaration
public virtual void Search(Query query, ICollector results)
Parameters
Type Name Description
Query query
ICollector results
Exceptions
Type Condition
BooleanQuery.TooManyClausesException

If a query would exceed MaxClauseCount clauses.

| Improve this Doc View Source

Search(Query, Int32)

Finds the top n hits for query.

Declaration
public virtual TopDocs Search(Query query, int n)
Parameters
Type Name Description
Query query
System.Int32 n
Returns
Type Description
TopDocs
Exceptions
Type Condition
BooleanQuery.TooManyClausesException

If a query would exceed MaxClauseCount clauses.

| Improve this Doc View Source

Search(Query, Int32, Sort)

Search implementation with arbitrary sorting and no filter.

Declaration
public virtual TopFieldDocs Search(Query query, int n, Sort sort)
Parameters
Type Name Description
Query query

The query to search for

System.Int32 n

Return only the top n results

Sort sort

The Sort object

Returns
Type Description
TopFieldDocs

The top docs, sorted according to the supplied Sort instance

Exceptions
Type Condition
System.IO.IOException

if there is a low-level I/O error

| Improve this Doc View Source

Search(Weight, FieldDoc, Int32, Sort, Boolean, Boolean, Boolean)

Just like Search(Weight, Int32, Sort, Boolean, Boolean), but you choose whether or not the fields in the returned FieldDoc instances should be set by specifying fillFields.

Declaration
protected virtual TopFieldDocs Search(Weight weight, FieldDoc after, int nDocs, Sort sort, bool fillFields, bool doDocScores, bool doMaxScore)
Parameters
Type Name Description
Weight weight
FieldDoc after
System.Int32 nDocs
Sort sort
System.Boolean fillFields
System.Boolean doDocScores
System.Boolean doMaxScore
Returns
Type Description
TopFieldDocs
| Improve this Doc View Source

Search(Weight, ScoreDoc, Int32)

Expert: Low-level search implementation. Finds the top nDocs hits for query, applying filter if non-null.

Applications should usually call Search(Query, Int32) or Search(Query, Filter, Int32) instead.

Declaration
protected virtual TopDocs Search(Weight weight, ScoreDoc after, int nDocs)
Parameters
Type Name Description
Weight weight
ScoreDoc after
System.Int32 nDocs
Returns
Type Description
TopDocs
Exceptions
Type Condition
BooleanQuery.TooManyClausesException

If a query would exceed MaxClauseCount clauses.

| Improve this Doc View Source

Search(Weight, Int32, Sort, Boolean, Boolean)

Expert: Low-level search implementation with arbitrary sorting and control over whether hit scores and max score should be computed. Finds the top nDocs hits for query and sorting the hits by the criteria in sort.

Applications should usually call Search(Query, Filter, Int32, Sort) instead.

Declaration
protected virtual TopFieldDocs Search(Weight weight, int nDocs, Sort sort, bool doDocScores, bool doMaxScore)
Parameters
Type Name Description
Weight weight
System.Int32 nDocs
Sort sort
System.Boolean doDocScores
System.Boolean doMaxScore
Returns
Type Description
TopFieldDocs
Exceptions
Type Condition
BooleanQuery.TooManyClausesException

If a query would exceed MaxClauseCount clauses.

| Improve this Doc View Source

Search(IList<AtomicReaderContext>, Weight, FieldDoc, Int32, Sort, Boolean, Boolean, Boolean)

Just like Search(Weight, Int32, Sort, Boolean, Boolean), but you choose whether or not the fields in the returned FieldDoc instances should be set by specifying fillFields.

Declaration
protected virtual TopFieldDocs Search(IList<AtomicReaderContext> leaves, Weight weight, FieldDoc after, int nDocs, Sort sort, bool fillFields, bool doDocScores, bool doMaxScore)
Parameters
Type Name Description
System.Collections.Generic.IList<AtomicReaderContext> leaves
Weight weight
FieldDoc after
System.Int32 nDocs
Sort sort
System.Boolean fillFields
System.Boolean doDocScores
System.Boolean doMaxScore
Returns
Type Description
TopFieldDocs
| Improve this Doc View Source

Search(IList<AtomicReaderContext>, Weight, ICollector)

Lower-level search API.

Collect(Int32) is called for every document.

NOTE: this method executes the searches on all given leaves exclusively. To search across all the searchers leaves use m_leafContexts.

Declaration
protected virtual void Search(IList<AtomicReaderContext> leaves, Weight weight, ICollector collector)
Parameters
Type Name Description
System.Collections.Generic.IList<AtomicReaderContext> leaves

The searchers leaves to execute the searches on

Weight weight

To match documents

ICollector collector

To receive hits

Exceptions
Type Condition
BooleanQuery.TooManyClausesException

If a query would exceed MaxClauseCount clauses.

| Improve this Doc View Source

Search(IList<AtomicReaderContext>, Weight, ScoreDoc, Int32)

Expert: Low-level search implementation. Finds the top 

n
hits for query.

Applications should usually call Search(Query, Int32) or Search(Query, Filter, Int32) instead.

Declaration
protected virtual TopDocs Search(IList<AtomicReaderContext> leaves, Weight weight, ScoreDoc after, int nDocs)
Parameters
Type Name Description
System.Collections.Generic.IList<AtomicReaderContext> leaves
Weight weight
ScoreDoc after
System.Int32 nDocs
Returns
Type Description
TopDocs
Exceptions
Type Condition
BooleanQuery.TooManyClausesException

If a query would exceed MaxClauseCount clauses.

| Improve this Doc View Source

SearchAfter(ScoreDoc, Query, Filter, Int32)

Finds the top n hits for query, applying filter if non-null, where all results are after a previous result (after).

By passing the bottom result from a previous page as after, this method can be used for efficient 'deep-paging' across potentially large result sets.

Declaration
public virtual TopDocs SearchAfter(ScoreDoc after, Query query, Filter filter, int n)
Parameters
Type Name Description
ScoreDoc after
Query query
Filter filter
System.Int32 n
Returns
Type Description
TopDocs
Exceptions
Type Condition
BooleanQuery.TooManyClausesException

If a query would exceed MaxClauseCount clauses.

| Improve this Doc View Source

SearchAfter(ScoreDoc, Query, Filter, Int32, Sort)

Finds the top n hits for query, applying filter if non-null, where all results are after a previous result (after).

By passing the bottom result from a previous page as after, this method can be used for efficient 'deep-paging' across potentially large result sets.

Declaration
public virtual TopDocs SearchAfter(ScoreDoc after, Query query, Filter filter, int n, Sort sort)
Parameters
Type Name Description
ScoreDoc after
Query query
Filter filter
System.Int32 n
Sort sort
Returns
Type Description
TopDocs
Exceptions
Type Condition
BooleanQuery.TooManyClausesException

If a query would exceed MaxClauseCount clauses.

| Improve this Doc View Source

SearchAfter(ScoreDoc, Query, Filter, Int32, Sort, Boolean, Boolean)

Finds the top n hits for query where all results are after a previous result (after), allowing control over whether hit scores and max score should be computed.

By passing the bottom result from a previous page as after, this method can be used for efficient 'deep-paging' across potentially large result sets. If doDocScores is true then the score of each hit will be computed and returned. If doMaxScore is true then the maximum score over all collected hits will be computed.

Declaration
public virtual TopDocs SearchAfter(ScoreDoc after, Query query, Filter filter, int n, Sort sort, bool doDocScores, bool doMaxScore)
Parameters
Type Name Description
ScoreDoc after
Query query
Filter filter
System.Int32 n
Sort sort
System.Boolean doDocScores
System.Boolean doMaxScore
Returns
Type Description
TopDocs
Exceptions
Type Condition
BooleanQuery.TooManyClausesException

If a query would exceed MaxClauseCount clauses.

| Improve this Doc View Source

SearchAfter(ScoreDoc, Query, Int32)

Finds the top n hits for top query where all results are after a previous result (top after).

By passing the bottom result from a previous page as after, this method can be used for efficient 'deep-paging' across potentially large result sets.

Declaration
public virtual TopDocs SearchAfter(ScoreDoc after, Query query, int n)
Parameters
Type Name Description
ScoreDoc after
Query query
System.Int32 n
Returns
Type Description
TopDocs
Exceptions
Type Condition
BooleanQuery.TooManyClausesException

If a query would exceed MaxClauseCount clauses.

| Improve this Doc View Source

SearchAfter(ScoreDoc, Query, Int32, Sort)

Finds the top n hits for query where all results are after a previous result (after).

By passing the bottom result from a previous page as after, this method can be used for efficient 'deep-paging' across potentially large result sets.

Declaration
public virtual TopDocs SearchAfter(ScoreDoc after, Query query, int n, Sort sort)
Parameters
Type Name Description
ScoreDoc after
Query query
System.Int32 n
Sort sort
Returns
Type Description
TopDocs
Exceptions
Type Condition
BooleanQuery.TooManyClausesException

If a query would exceed MaxClauseCount clauses.

| Improve this Doc View Source

Slices(IList<AtomicReaderContext>)

Expert: Creates an array of leaf slices each holding a subset of the given leaves. Each IndexSearcher.LeafSlice is executed in a single thread. By default there will be one IndexSearcher.LeafSlice per leaf (AtomicReaderContext).

Declaration
protected virtual IndexSearcher.LeafSlice[] Slices(IList<AtomicReaderContext> leaves)
Parameters
Type Name Description
System.Collections.Generic.IList<AtomicReaderContext> leaves
Returns
Type Description
IndexSearcher.LeafSlice[]
| Improve this Doc View Source

TermStatistics(Term, TermContext)

Returns TermStatistics for a term.

This can be overridden for example, to return a term's statistics across a distributed collection.

This is a Lucene.NET EXPERIMENTAL API, use at your own risk
Declaration
public virtual TermStatistics TermStatistics(Term term, TermContext context)
Parameters
Type Name Description
Term term
TermContext context
Returns
Type Description
TermStatistics
| Improve this Doc View Source

ToString()

Declaration
public override string ToString()
Returns
Type Description
System.String
Overrides
System.Object.ToString()
| Improve this Doc View Source

WrapFilter(Query, Filter)

This is a Lucene.NET INTERNAL API, use at your own risk

Declaration
protected virtual Query WrapFilter(Query query, Filter filter)
Parameters
Type Name Description
Query query
Filter filter
Returns
Type Description
Query