Class AtomicReader

AtomicReader is an abstract class, providing an interface for accessing an index. Search of an index is done entirely through this abstract interface, so that any subclass which implements it is searchable. IndexReaders implemented by this subclass do not consist of several sub-readers, they are atomic. They support retrieval of stored fields, doc values, terms, and postings.

For efficiency, in this API documents are often referred to via document numbers, non-negative integers which each name a unique document in the index. These document numbers are ephemeral -- they may change as documents are added to and deleted from an index. Clients should thus not rely on a given document having the same number between sessions.

NOTE: IndexReader 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 IndexReader instance; use your own (non-Lucene) objects instead.
Inheritance
object
IndexReader
AtomicReader
FilterAtomicReader
ParallelAtomicReader
SegmentReader
SlowCompositeReaderWrapper
Implements
Inherited Members
Namespace: Lucene.Net.Index
Assembly: Lucene.Net.dll
Syntax
public abstract class AtomicReader : IndexReader, IDisposable

Constructors

AtomicReader()

Sole constructor. (For invocation by subclass constructors, typically implicit.)

Declaration
protected AtomicReader()

Properties

AtomicContext

LUCENENET specific propety that allows access to the context as AtomicReaderContext, which prevents the need to cast.

Declaration
public AtomicReaderContext AtomicContext { get; }
Property Value
Type Description
AtomicReaderContext

Context

Expert: Returns the root IndexReaderContext for this IndexReader's sub-reader tree.

Iff this reader is composed of sub readers, i.e. this reader being a composite reader, this method returns a CompositeReaderContext holding the reader's direct children as well as a view of the reader tree's atomic leaf contexts. All sub- IndexReaderContext instances referenced from this readers top-level context are private to this reader and are not shared with another context tree. For example, IndexSearcher uses this API to drive searching by one atomic leaf reader at a time. If this reader is not composed of child readers, this method returns an AtomicReaderContext.

Note: Any of the sub-CompositeReaderContext instances referenced from this top-level context do not support Leaves. Only the top-level context maintains the convenience leaf-view for performance reasons.
Declaration
public override sealed IndexReaderContext Context { get; }
Property Value
Type Description
IndexReaderContext
Overrides

FieldInfos

Get the FieldInfos describing all fields in this reader.

Note

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

Declaration
public abstract FieldInfos FieldInfos { get; }
Property Value
Type Description
FieldInfos

Fields

Returns Fields for this reader. this property may return null if the reader has no postings.

Declaration
public abstract Fields Fields { get; }
Property Value
Type Description
Fields

LiveDocs

Returns the IBits representing live (not deleted) docs. A set bit indicates the doc ID has not been deleted. If this method returns null it means there are no deleted documents (all documents are live).

The returned instance has been safely published for use by multiple threads without additional synchronization.
Declaration
public abstract IBits LiveDocs { get; }
Property Value
Type Description
IBits

Methods

CheckIntegrity()

Checks consistency of this reader.

Note that this may be costly in terms of I/O, e.g. may involve computing a checksum value against large data files.

Note

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

Declaration
public abstract void CheckIntegrity()

DocFreq(Term)

Returns the number of documents containing the term. This method returns 0 if the term or field does not exist. This method does not take into account deleted documents that have not yet been merged away.

Declaration
public override sealed int DocFreq(Term term)
Parameters
Type Name Description
Term term
Returns
Type Description
int
Overrides
See Also

GetBinaryDocValues(string)

Returns BinaryDocValues for this field, or null if no BinaryDocValues were indexed for this field. The returned instance should only be used by a single thread.

Declaration
public abstract BinaryDocValues GetBinaryDocValues(string field)
Parameters
Type Name Description
string field
Returns
Type Description
BinaryDocValues

GetDocCount(string)

Returns the number of documents that have at least one term for this field, or -1 if this measure isn't stored by the codec. Note that, just like other term measures, this measure does not take deleted documents into account.

Declaration
public override sealed int GetDocCount(string field)
Parameters
Type Name Description
string field
Returns
Type Description
int
Overrides
See Also

GetDocsWithField(string)

Returns a IBits at the size of reader.MaxDoc, with turned on bits for each docid that does have a value for this field, or null if no DocValues were indexed for this field. The returned instance should only be used by a single thread.

Declaration
public abstract IBits GetDocsWithField(string field)
Parameters
Type Name Description
string field
Returns
Type Description
IBits

GetNormValues(string)

Returns NumericDocValues representing norms for this field, or null if no NumericDocValues were indexed. The returned instance should only be used by a single thread.

Declaration
public abstract NumericDocValues GetNormValues(string field)
Parameters
Type Name Description
string field
Returns
Type Description
NumericDocValues

GetNumericDocValues(string)

Returns NumericDocValues for this field, or null if no NumericDocValues were indexed for this field. The returned instance should only be used by a single thread.

Declaration
public abstract NumericDocValues GetNumericDocValues(string field)
Parameters
Type Name Description
string field
Returns
Type Description
NumericDocValues

GetSortedDocValues(string)

Returns SortedDocValues for this field, or null if no SortedDocValues were indexed for this field. The returned instance should only be used by a single thread.

Declaration
public abstract SortedDocValues GetSortedDocValues(string field)
Parameters
Type Name Description
string field
Returns
Type Description
SortedDocValues

GetSortedSetDocValues(string)

Returns SortedSetDocValues for this field, or null if no SortedSetDocValues were indexed for this field. The returned instance should only be used by a single thread.

Declaration
public abstract SortedSetDocValues GetSortedSetDocValues(string field)
Parameters
Type Name Description
string field
Returns
Type Description
SortedSetDocValues

GetSumDocFreq(string)

Returns the sum of DocFreq for all terms in this field, or -1 if this measure isn't stored by the codec. Note that, just like other term measures, this measure does not take deleted documents into account.

Declaration
public override sealed long GetSumDocFreq(string field)
Parameters
Type Name Description
string field
Returns
Type Description
long
Overrides
See Also

GetSumTotalTermFreq(string)

Returns the sum of TotalTermFreq for all terms in this field, or -1 if this measure isn't stored by the codec (or if this fields omits term freq and positions). Note that, just like other term measures, this measure does not take deleted documents into account.

Declaration
public override sealed long GetSumTotalTermFreq(string field)
Parameters
Type Name Description
string field
Returns
Type Description
long
Overrides
See Also

GetTermDocsEnum(Term)

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

Declaration
public DocsEnum GetTermDocsEnum(Term term)
Parameters
Type Name Description
Term term
Returns
Type Description
DocsEnum
See Also

GetTermPositionsEnum(Term)

Returns DocsAndPositionsEnum for the specified term. This will return null if the field or term does not exist or positions weren't indexed.

Declaration
public DocsAndPositionsEnum GetTermPositionsEnum(Term term)
Parameters
Type Name Description
Term term
Returns
Type Description
DocsAndPositionsEnum
See Also

GetTerms(string)

This may return null if the field does not exist.

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

HasNorms(string)

Returns true if there are norms stored for this field.

Declaration
[Obsolete("(4.0) use FieldInfos and check FieldInfo.HasNorms for the field instead.")]
public bool HasNorms(string field)
Parameters
Type Name Description
string field
Returns
Type Description
bool

TotalTermFreq(Term)

Returns the number of documents containing the term. This method returns 0 if the term or field does not exist. This method does not take into account deleted documents that have not yet been merged away.

Declaration
public override sealed long TotalTermFreq(Term term)
Parameters
Type Name Description
Term term
Returns
Type Description
long
Overrides

Implements