Package org.apache.lucene.index

Class OrdinalMap

java.lang.Object

org.apache.lucene.index.OrdinalMap

All Implemented Interfaces:

Accountable

public class OrdinalMap
extends Object
implements Accountable

Maps per-segment ordinals to/from global ordinal space, using a compact packed-ints representation.

NOTE: this is a costly operation, as it must merge sort all terms, and may require non-trivial RAM once done. It's better to operate in segment-private ordinal space instead when possible.

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

Field Summary

Fields

Modifier and Type	Field	Description
IndexReader.CacheKey	owner	Cache key of whoever asked for this awful thing

Fields inherited from interface org.apache.lucene.util.Accountable

NULL_ACCOUNTABLE

Method Summary

Modifier and Type	Method	Description
static OrdinalMap	build(IndexReader.CacheKey owner, SortedDocValues[] values, float acceptableOverheadRatio)	Create an ordinal map that uses the number of unique values of each SortedDocValues instance as a weight.
static OrdinalMap	build(IndexReader.CacheKey owner, SortedSetDocValues[] values, float acceptableOverheadRatio)	Create an ordinal map that uses the number of unique values of each SortedSetDocValues instance as a weight.
static OrdinalMap	build(IndexReader.CacheKey owner, TermsEnum[] subs, long[] weights, float acceptableOverheadRatio)	Creates an ordinal map that allows mapping ords to/from a merged space from subs.
Collection<Accountable>	getChildResources()	Returns nested resources of this class.
int	getFirstSegmentNumber(long globalOrd)	Given a global ordinal, returns the index of the first segment that contains this term.
long	getFirstSegmentOrd(long globalOrd)	Given global ordinal, returns the ordinal of the first segment which contains this ordinal (the corresponding to the segment return getFirstSegmentNumber(long)).
LongValues	getGlobalOrds(int segmentIndex)	Given a segment number, return a LongValues instance that maps segment ordinals to global ordinals.
long	getValueCount()	Returns the total number of unique terms in global ord space.
long	ramBytesUsed()	Return the memory usage of this object in bytes.

Methods inherited from class java.lang.Object

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

Field Detail

owner

public final IndexReader.CacheKey owner

Cache key of whoever asked for this awful thing

Method Detail

build

public static OrdinalMap build(IndexReader.CacheKey owner,
                               SortedDocValues[] values,
                               float acceptableOverheadRatio)
                        throws IOException

Create an ordinal map that uses the number of unique values of each SortedDocValues instance as a weight.

Throws:

IOException

See Also:

build(IndexReader.CacheKey, TermsEnum[], long[], float)

build

public static OrdinalMap build(IndexReader.CacheKey owner,
                               SortedSetDocValues[] values,
                               float acceptableOverheadRatio)
                        throws IOException

Create an ordinal map that uses the number of unique values of each SortedSetDocValues instance as a weight.

Throws:

IOException

See Also:

build(IndexReader.CacheKey, TermsEnum[], long[], float)

build

public static OrdinalMap build(IndexReader.CacheKey owner,
                               TermsEnum[] subs,
                               long[] weights,
                               float acceptableOverheadRatio)
                        throws IOException

Creates an ordinal map that allows mapping ords to/from a merged space from subs.

Parameters:

owner - a cache key

subs - TermsEnums that support TermsEnum.ord(). They need not be dense (e.g. can be FilteredTermsEnums}.

weights - a weight for each sub. This is ideally correlated with the number of unique terms that each sub introduces compared to the other subs

Throws:

IOException - if an I/O error occurred.

getGlobalOrds

public LongValues getGlobalOrds(int segmentIndex)

Given a segment number, return a LongValues instance that maps segment ordinals to global ordinals.

getFirstSegmentOrd

public long getFirstSegmentOrd(long globalOrd)

Given global ordinal, returns the ordinal of the first segment which contains this ordinal (the corresponding to the segment return getFirstSegmentNumber(long)).

getFirstSegmentNumber

public int getFirstSegmentNumber(long globalOrd)

Given a global ordinal, returns the index of the first segment that contains this term.

getValueCount

public long getValueCount()

Returns the total number of unique terms in global ord space.

ramBytesUsed

public long ramBytesUsed()

Description copied from interface: Accountable

Return the memory usage of this object in bytes. Negative values are illegal.

Specified by:

ramBytesUsed in interface Accountable

getChildResources

public Collection<Accountable> getChildResources()

Description copied from interface: Accountable

Returns nested resources of this class. The result should be a point-in-time snapshot (to avoid race conditions).

Specified by:

getChildResources in interface Accountable

See Also:

Accountables