Package org.apache.lucene.facet.taxonomy.directory

Class DirectoryTaxonomyReader

java.lang.Object

org.apache.lucene.facet.taxonomy.TaxonomyReader

org.apache.lucene.facet.taxonomy.directory.DirectoryTaxonomyReader

All Implemented Interfaces:

java.io.Closeable, java.lang.AutoCloseable

public class DirectoryTaxonomyReader
extends TaxonomyReader

A TaxonomyReader which retrieves stored taxonomy information from a 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.

Nested Class Summary

Nested classes/interfaces inherited from class org.apache.lucene.facet.taxonomy.TaxonomyReader

TaxonomyReader.ChildrenIterator

Field Summary

Fields inherited from class org.apache.lucene.facet.taxonomy.TaxonomyReader

INVALID_ORDINAL, ROOT_ORDINAL

Constructor Summary

Constructors

Constructor	Description
DirectoryTaxonomyReader(DirectoryTaxonomyWriter taxoWriter)	Opens a DirectoryTaxonomyReader over the given DirectoryTaxonomyWriter (for NRT).
DirectoryTaxonomyReader(Directory directory)	Open for reading a taxonomy stored in a given Directory.

Method Summary

Modifier and Type	Method	Description
java.util.Map<java.lang.String,java.lang.String>	getCommitUserData()	Retrieve user committed data.
int	getOrdinal(FacetLabel cp)	Returns the ordinal of the category given as a path.
ParallelTaxonomyArrays	getParallelTaxonomyArrays()	Returns a ParallelTaxonomyArrays object which can be used to efficiently traverse the taxonomy tree.
FacetLabel	getPath(int ordinal)	Returns the path name of the category with the given ordinal.
int	getSize()	Returns the number of categories in the taxonomy.
void	setCacheSize(int size)	setCacheSize controls the maximum allowed size of each of the caches used by getPath(int) and getOrdinal(FacetLabel).
java.lang.String	toString(int max)	Returns ordinal -> label mapping, up to the provided max ordinal or number of ordinals, whichever is smaller.

Methods inherited from class org.apache.lucene.facet.taxonomy.TaxonomyReader

close, decRef, getChildren, getOrdinal, getRefCount, incRef, openIfChanged, tryIncRef

Methods inherited from class java.lang.Object

equals, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Constructor Detail

DirectoryTaxonomyReader

public DirectoryTaxonomyReader(Directory directory)
                        throws java.io.IOException

Open for reading a taxonomy stored in a given Directory.

Parameters:

directory - The Directory in which the taxonomy resides.

Throws:

CorruptIndexException - if the Taxonomy is corrupt.

java.io.IOException - if another error occurred.

DirectoryTaxonomyReader

public DirectoryTaxonomyReader(DirectoryTaxonomyWriter taxoWriter)
                        throws java.io.IOException

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

Parameters:

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

Throws:

java.io.IOException

Method Detail

getParallelTaxonomyArrays

public ParallelTaxonomyArrays getParallelTaxonomyArrays()
                                                 throws java.io.IOException

Description copied from class: TaxonomyReader

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

Specified by:

getParallelTaxonomyArrays in class TaxonomyReader

Throws:

java.io.IOException

getCommitUserData

public java.util.Map<java.lang.String,java.lang.String> getCommitUserData()
                                                                         throws java.io.IOException

Description copied from class: TaxonomyReader

Retrieve user committed data.

Specified by:

getCommitUserData in class TaxonomyReader

Throws:

java.io.IOException

See Also:

TaxonomyWriter.setCommitData(Map)

getOrdinal

public int getOrdinal(FacetLabel cp)
               throws java.io.IOException

Description copied from class: TaxonomyReader

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).

Specified by:

getOrdinal in class TaxonomyReader

Returns:

the category's ordinal or TaxonomyReader.INVALID_ORDINAL if the category wasn't foun.

Throws:

java.io.IOException

getPath

public FacetLabel getPath(int ordinal)
                   throws java.io.IOException

Description copied from class: TaxonomyReader

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

Specified by:

getPath in class TaxonomyReader

Throws:

java.io.IOException

getSize

public int getSize()

Description copied from class: TaxonomyReader

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).

Specified by:

getSize in class TaxonomyReader

setCacheSize

public void setCacheSize(int size)

setCacheSize 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.

Parameters:

size - the new maximum cache size, in number of entries.

toString

public java.lang.String toString(int max)

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