Class MultiFields

Exposes flex API, merged from flex API of sub-segments. This is useful when you're interacting with an IndexReader implementation that consists of sequential sub-readers (eg DirectoryReader or MultiReader).

NOTE: for composite readers, you'll get better performance by gathering the sub readers using Context to get the atomic leaves and then operate per-AtomicReader, instead of using this class.

Note

This API is experimental and might change in incompatible ways in the next release.

Inheritance
object
Fields
MultiFields
Inherited Members
Namespace: Lucene.Net.Index
Assembly: Lucene.Net.dll
Syntax
public sealed class MultiFields : Fields, IEnumerable<string>, IEnumerable

Constructors

MultiFields(Fields[], ReaderSlice[])

Expert: construct a new MultiFields instance directly.

Note

This API is for internal purposes only and might change in incompatible ways in the next release.

Declaration
public MultiFields(Fields[] subs, ReaderSlice[] subSlices)
Parameters
Type Name Description
Fields[] subs
ReaderSlice[] subSlices

Properties

Count

Gets the number of fields or -1 if the number of distinct field names is unknown. If >= 0, GetEnumerator() will return as many field names.

NOTE: This was size() in Lucene.
Declaration
public override int Count { get; }
Property Value
Type Description
int
Overrides

Methods

GetEnumerator()

Returns an enumerator that will step through all field names. This will not return null.

Declaration
public override IEnumerator<string> GetEnumerator()
Returns
Type Description
IEnumerator<string>
Overrides

GetFields(IndexReader)

Returns a single Fields instance for this reader, merging fields/terms/docs/positions on the fly. This method will return null if the reader has no postings.

NOTE: this is a slow way to access postings. It's better to get the sub-readers and iterate through them yourself.
Declaration
public static Fields GetFields(IndexReader reader)
Parameters
Type Name Description
IndexReader reader
Returns
Type Description
Fields

GetIndexedFields(IndexReader)

Call this to get the (merged) FieldInfos representing the set of indexed fields only for a composite reader.

NOTE: the returned field numbers will likely not correspond to the actual field numbers in the underlying readers, and codec metadata (GetAttribute(string)) will be unavailable.
Declaration
public static ICollection<string> GetIndexedFields(IndexReader reader)
Parameters
Type Name Description
IndexReader reader
Returns
Type Description
ICollection<string>

GetLiveDocs(IndexReader)

Returns a single IBits instance for this reader, merging live Documents on the fly. This method will return null if the reader has no deletions.

NOTE: this is a very slow way to access live docs. For example, each IBits access will require a binary search. It's better to get the sub-readers and iterate through them yourself.
Declaration
public static IBits GetLiveDocs(IndexReader reader)
Parameters
Type Name Description
IndexReader reader
Returns
Type Description
IBits

GetMergedFieldInfos(IndexReader)

Call this to get the (merged) FieldInfos for a composite reader.

NOTE: the returned field numbers will likely not correspond to the actual field numbers in the underlying readers, and codec metadata (GetAttribute(string)) will be unavailable.
Declaration
public static FieldInfos GetMergedFieldInfos(IndexReader reader)
Parameters
Type Name Description
IndexReader reader
Returns
Type Description
FieldInfos

GetTermDocsEnum(IndexReader, IBits, string, BytesRef)

Returns DocsEnum for the specified field & term. This will return null if the field or term does not exist.

Declaration
public static DocsEnum GetTermDocsEnum(IndexReader r, IBits liveDocs, string field, BytesRef term)
Parameters
Type Name Description
IndexReader r
IBits liveDocs
string field
BytesRef term
Returns
Type Description
DocsEnum

GetTermDocsEnum(IndexReader, IBits, string, BytesRef, DocsFlags)

Returns DocsEnum for the specified field & term, with control over whether freqs are required. Some codecs may be able to optimize their implementation when freqs are not required. This will return null if the field or term does not exist. See Docs(IBits, DocsEnum, DocsFlags).

Declaration
public static DocsEnum GetTermDocsEnum(IndexReader r, IBits liveDocs, string field, BytesRef term, DocsFlags flags)
Parameters
Type Name Description
IndexReader r
IBits liveDocs
string field
BytesRef term
DocsFlags flags
Returns
Type Description
DocsEnum

GetTermPositionsEnum(IndexReader, IBits, string, BytesRef)

Returns DocsAndPositionsEnum for the specified field & term. This will return null if the field or term does not exist or positions were not indexed.

Declaration
public static DocsAndPositionsEnum GetTermPositionsEnum(IndexReader r, IBits liveDocs, string field, BytesRef term)
Parameters
Type Name Description
IndexReader r
IBits liveDocs
string field
BytesRef term
Returns
Type Description
DocsAndPositionsEnum
See Also

GetTermPositionsEnum(IndexReader, IBits, string, BytesRef, DocsAndPositionsFlags)

Returns DocsAndPositionsEnum for the specified field & term, with control over whether offsets and payloads are required. Some codecs may be able to optimize their implementation when offsets and/or payloads are not required. This will return null if the field or term does not exist or positions were not indexed. See DocsAndPositions(IBits, DocsAndPositionsEnum, DocsAndPositionsFlags).

Declaration
public static DocsAndPositionsEnum GetTermPositionsEnum(IndexReader r, IBits liveDocs, string field, BytesRef term, DocsAndPositionsFlags flags)
Parameters
Type Name Description
IndexReader r
IBits liveDocs
string field
BytesRef term
DocsAndPositionsFlags flags
Returns
Type Description
DocsAndPositionsEnum

GetTerms(IndexReader, string)

this method may return null if the field does not exist.

Declaration
public static Terms GetTerms(IndexReader r, string field)
Parameters
Type Name Description
IndexReader r
string field
Returns
Type Description
Terms

GetTerms(string)

Get the Terms for this field. This will return null if the field does not exist.

Declaration
public override Terms GetTerms(string field)
Parameters
Type Name Description
string field
Returns
Type Description
Terms
Overrides

Implements