Class DirectoryTaxonomyReader

A TaxonomyReader which retrieves stored taxonomy information from a Lucene.Net.Store.Directory.

Reading from the on-disk index on every method call is too slow, so this implementation employs caching: Some methods cache recent requests and their results, while other methods prefetch all the data into memory and then provide answers directly from in-memory tables. See the documentation of individual methods for comments on their performance.

Note

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

Inheritance

object

TaxonomyReader

DirectoryTaxonomyReader

Implements

IDisposable

Inherited Members

TaxonomyReader.ROOT_ORDINAL

TaxonomyReader.INVALID_ORDINAL

TaxonomyReader.OpenIfChanged<T>(T)

TaxonomyReader.EnsureOpen()

TaxonomyReader.Dispose()

TaxonomyReader.DecRef()

TaxonomyReader.GetChildren(int)

TaxonomyReader.GetOrdinal(string, string[])

TaxonomyReader.RefCount

TaxonomyReader.IncRef()

TaxonomyReader.TryIncRef()

object.Equals(object)

object.Equals(object, object)

object.GetHashCode()

object.GetType()

object.MemberwiseClone()

object.ReferenceEquals(object, object)

object.ToString()

Namespace: Lucene.Net.Facet.Taxonomy.Directory

Assembly: Lucene.Net.Facet.dll

Syntax

public class DirectoryTaxonomyReader : TaxonomyReader, IDisposable

Constructors

DirectoryTaxonomyReader(DirectoryTaxonomyIndexReaderFactory, DirectoryTaxonomyWriter)

Opens a DirectoryTaxonomyReader over the given DirectoryTaxonomyWriter (for NRT).

Declaration

public DirectoryTaxonomyReader(DirectoryTaxonomyIndexReaderFactory indexReaderFactory, DirectoryTaxonomyWriter taxoWriter)

Parameters

Type	Name	Description
DirectoryTaxonomyIndexReaderFactory	indexReaderFactory	The DirectoryTaxonomyIndexReaderFactory to use to open the index reader.
DirectoryTaxonomyWriter	taxoWriter	The DirectoryTaxonomyWriter from which to obtain newly added categories, in real-time.

Exceptions

Type	Condition
ArgumentNullException	if indexReaderFactory or taxoWriter is null.

DirectoryTaxonomyReader(DirectoryTaxonomyIndexReaderFactory, Directory)

Open for reading a taxonomy stored in a given Lucene.Net.Store.Directory.

Declaration

public DirectoryTaxonomyReader(DirectoryTaxonomyIndexReaderFactory indexReaderFactory, Directory directory)

Parameters

Type	Name	Description
DirectoryTaxonomyIndexReaderFactory	indexReaderFactory	The DirectoryTaxonomyIndexReaderFactory to use to open the index reader.
Directory	directory	The Lucene.Net.Store.Directory in which the taxonomy resides.

Exceptions

Type	Condition
CorruptIndexException	if the Taxonomy is corrupt.
IOException	if another error occurred.

DirectoryTaxonomyReader(DirectoryTaxonomyWriter)

Opens a DirectoryTaxonomyReader over the given DirectoryTaxonomyWriter (for NRT). Uses Default for DirectoryTaxonomyIndexReaderFactory.

Declaration

public DirectoryTaxonomyReader(DirectoryTaxonomyWriter taxoWriter)

Parameters

Type	Name	Description
DirectoryTaxonomyWriter	taxoWriter	The DirectoryTaxonomyWriter from which to obtain newly added categories, in real-time.

DirectoryTaxonomyReader(Directory)

Open for reading a taxonomy stored in a given Lucene.Net.Store.Directory. Uses Default as for DirectoryTaxonomyIndexReaderFactory.

Declaration

public DirectoryTaxonomyReader(Directory directory)

Parameters

Type	Name	Description
Directory	directory	The Lucene.Net.Store.Directory in which the taxonomy resides.

Exceptions

Type	Condition
CorruptIndexException	if the Taxonomy is corrupt.
IOException	if another error occurred.

Properties

CommitUserData

Retrieve user committed data.

Declaration

public override IDictionary<string, string> CommitUserData { get; }

Property Value

Type	Description
IDictionary<string, string>

Overrides

TaxonomyReader.CommitUserData

See Also

CommitData

Count

Returns the number of categories in the taxonomy. Note that the number of categories returned is often slightly higher than the number of categories inserted into the taxonomy; This is because when a category is added to the taxonomy, its ancestors are also added automatically (including the root, which always get ordinal 0).

Declaration

public override int Count { get; }

Property Value

Type	Description
int

Overrides

TaxonomyReader.Count

ParallelTaxonomyArrays

Returns a ParallelTaxonomyArrays object which can be used to efficiently traverse the taxonomy tree.

Declaration

public override ParallelTaxonomyArrays ParallelTaxonomyArrays { get; }

Property Value

Type	Description
ParallelTaxonomyArrays

Overrides

TaxonomyReader.ParallelTaxonomyArrays

Methods

Dispose(bool)

Performs the actual task of closing the resources that are used by the taxonomy reader.

Declaration

protected override void Dispose(bool disposing)

Parameters

Type	Name	Description
bool	disposing

Overrides

TaxonomyReader.Dispose(bool)

DoOpenIfChanged()

Implements the opening of a new DirectoryTaxonomyReader instance if the taxonomy has changed.

NOTE: the returned DirectoryTaxonomyReader shares the ordinal and category caches with this reader. This is not expected to cause any issues, unless the two instances continue to live. The reader guarantees that the two instances cannot affect each other in terms of correctness of the caches, however if the size of the cache is changed through SetCacheSize(int), it will affect both reader instances.

Declaration

protected override TaxonomyReader DoOpenIfChanged()

Returns

Type	Description
TaxonomyReader

Overrides

TaxonomyReader.DoOpenIfChanged()

GetOrdinal(FacetLabel)

Returns the ordinal of the category given as a path. The ordinal is the category's serial number, an integer which starts with 0 and grows as more categories are added (note that once a category is added, it can never be deleted).

Declaration

public override int GetOrdinal(FacetLabel cp)

Parameters

Type	Name	Description
FacetLabel	cp

Returns

Type	Description
int	the category's ordinal or INVALID_ORDINAL if the category wasn't found.

Overrides

TaxonomyReader.GetOrdinal(FacetLabel)

GetPath(int)

Returns the path name of the category with the given ordinal.

Declaration

public override FacetLabel GetPath(int ordinal)

Parameters

Type	Name	Description
int	ordinal

Returns

Type	Description
FacetLabel

Overrides

TaxonomyReader.GetPath(int)

SetCacheSize(int)

SetCacheSize(int) controls the maximum allowed size of each of the caches used by GetPath(int) and GetOrdinal(FacetLabel).

Currently, if the given size is smaller than the current size of a cache, it will not shrink, and rather we be limited to its current size.

Declaration

public virtual void SetCacheSize(int size)

Parameters

Type	Name	Description
int	size	The new maximum cache size, in number of entries.

ToString(int)

Returns ordinal -> label mapping, up to the provided max ordinal or number of ordinals, whichever is smaller.

Declaration

public virtual string ToString(int max)

Parameters

Type	Name	Description
int	max

Returns

Type	Description
string

Implements

IDisposable