Package org.apache.lucene.index

Class ParallelLeafReader

java.lang.Object

org.apache.lucene.index.IndexReader

org.apache.lucene.index.LeafReader

org.apache.lucene.index.ParallelLeafReader

All Implemented Interfaces:

Closeable, AutoCloseable

public class ParallelLeafReader
extends LeafReader

An LeafReader which reads multiple, parallel indexes. Each index added must have the same number of documents, but typically each contains different fields. Deletions are taken from the first reader. Each document contains the union of the fields of all documents with the same document number. When searching, matches for a query term are from the first index added that has the field.

This is useful, e.g., with collections that have large fields which change rarely and small fields that change more frequently. The smaller fields may be re-indexed in a new index and both indexes may be searched together.

Warning: It is up to you to make sure all indexes are created and modified the same way. For example, if you add documents to one index, you need to add the same documents in the same order to the other indexes. Failure to do so will result in undefined behavior.

Nested Class Summary

Nested classes/interfaces inherited from class org.apache.lucene.index.IndexReader

IndexReader.CacheHelper, IndexReader.CacheKey, IndexReader.ClosedListener

Constructor Summary

Constructors

Constructor	Description
ParallelLeafReader(boolean closeSubReaders, LeafReader... readers)	Create a ParallelLeafReader based on the provided readers.
ParallelLeafReader(boolean closeSubReaders, LeafReader[] readers, LeafReader[] storedFieldsReaders)	Expert: create a ParallelLeafReader based on the provided readers and storedFieldReaders; when a document is loaded, only storedFieldsReaders will be used.
ParallelLeafReader(LeafReader... readers)	Create a ParallelLeafReader based on the provided readers; auto-closes the given readers on IndexReader.close().

Method Summary

Modifier and Type	Method	Description
void	checkIntegrity()	Checks consistency of this reader.
protected void	doClose()	Implements close.
void	document(int docID, StoredFieldVisitor visitor)	Expert: visits the fields of a stored document, for custom processing/loading of each field.
BinaryDocValues	getBinaryDocValues(String field)	Returns BinaryDocValues for this field, or null if no binary doc values were indexed for this field.
IndexReader.CacheHelper	getCoreCacheHelper()	Optional method: Return a IndexReader.CacheHelper that can be used to cache based on the content of this leaf regardless of deletions.
FieldInfos	getFieldInfos()	Get the FieldInfos describing all fields in this reader.
Bits	getLiveDocs()	Returns the Bits representing live (not deleted) docs.
LeafMetaData	getMetaData()	Return metadata about this leaf.
NumericDocValues	getNormValues(String field)	Returns NumericDocValues representing norms for this field, or null if no NumericDocValues were indexed.
NumericDocValues	getNumericDocValues(String field)	Returns NumericDocValues for this field, or null if no numeric doc values were indexed for this field.
LeafReader[]	getParallelReaders()	Returns the LeafReaders that were passed on init.
PointValues	getPointValues(String fieldName)	Returns the PointValues used for numeric or spatial searches for the given field, or null if there are no point fields.
IndexReader.CacheHelper	getReaderCacheHelper()	Optional method: Return a IndexReader.CacheHelper that can be used to cache based on the content of this reader.
SortedDocValues	getSortedDocValues(String field)	Returns SortedDocValues for this field, or null if no SortedDocValues were indexed for this field.
SortedNumericDocValues	getSortedNumericDocValues(String field)	Returns SortedNumericDocValues for this field, or null if no SortedNumericDocValues were indexed for this field.
SortedSetDocValues	getSortedSetDocValues(String field)	Returns SortedSetDocValues for this field, or null if no SortedSetDocValues were indexed for this field.
Fields	getTermVectors(int docID)	Retrieve term vectors for this document, or null if term vectors were not indexed.
VectorValues	getVectorValues(String fieldName)	Returns VectorValues for this field, or null if no VectorValues were indexed.
int	maxDoc()	Returns one greater than the largest possible document number.
int	numDocs()	Returns the number of documents in this index.
TopDocs	searchNearestVectors(String fieldName, float[] target, int k, Bits acceptDocs)	Return the k nearest neighbor documents as determined by comparison of their vector values for this field, to the given vector, by the field's search strategy.
Terms	terms(String field)	Returns the Terms index for this field, or null if it has none.
String	toString()

Methods inherited from class org.apache.lucene.index.LeafReader

docFreq, getContext, getDocCount, getSumDocFreq, getSumTotalTermFreq, postings, postings, totalTermFreq

Methods inherited from class org.apache.lucene.index.IndexReader

close, decRef, document, document, ensureOpen, equals, getRefCount, getTermVector, hasDeletions, hashCode, incRef, leaves, numDeletedDocs, registerParentReader, tryIncRef

Methods inherited from class java.lang.Object

clone, finalize, getClass, notify, notifyAll, wait, wait, wait

Constructor Detail

ParallelLeafReader

public ParallelLeafReader(LeafReader... readers)
                   throws IOException

Create a ParallelLeafReader based on the provided readers; auto-closes the given readers on IndexReader.close().

Throws:

IOException

ParallelLeafReader

public ParallelLeafReader(boolean closeSubReaders,
                          LeafReader... readers)
                   throws IOException

Create a ParallelLeafReader based on the provided readers.

Throws:

IOException

ParallelLeafReader

public ParallelLeafReader(boolean closeSubReaders,
                          LeafReader[] readers,
                          LeafReader[] storedFieldsReaders)
                   throws IOException

Expert: create a ParallelLeafReader based on the provided readers and storedFieldReaders; when a document is loaded, only storedFieldsReaders will be used.

Throws:

IOException

Method Detail

toString

public String toString()

Overrides:

toString in class Object

getFieldInfos

public FieldInfos getFieldInfos()

Get the FieldInfos describing all fields in this reader.

Note: Implementations should cache the FieldInfos instance returned by this method such that subsequent calls to this method return the same instance.

NOTE: the returned field numbers will likely not correspond to the actual field numbers in the underlying readers, and codec metadata (FieldInfo.getAttribute(String) will be unavailable.

Specified by:

getFieldInfos in class LeafReader

getLiveDocs

public Bits getLiveDocs()

Description copied from class: LeafReader

Returns the Bits 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.

Specified by:

getLiveDocs in class LeafReader

terms

public Terms terms(String field)
            throws IOException

Description copied from class: LeafReader

Returns the Terms index for this field, or null if it has none.

Specified by:

terms in class LeafReader

Throws:

IOException

numDocs

public int numDocs()

Description copied from class: IndexReader

Returns the number of documents in this index.

NOTE: This operation may run in O(maxDoc). Implementations that can't return this number in constant-time should cache it.

Specified by:

numDocs in class IndexReader

maxDoc

public int maxDoc()

Description copied from class: IndexReader

Returns one greater than the largest possible document number. This may be used to, e.g., determine how big to allocate an array which will have an element for every document number in an index.

Specified by:

maxDoc in class IndexReader

document

public void document(int docID,
                     StoredFieldVisitor visitor)
              throws IOException

Description copied from class: IndexReader

Expert: visits the fields of a stored document, for custom processing/loading of each field. If you simply want to load all fields, use IndexReader.document(int). If you want to load a subset, use DocumentStoredFieldVisitor.

Specified by:

document in class IndexReader

Throws:

IOException

getCoreCacheHelper

public IndexReader.CacheHelper getCoreCacheHelper()

Description copied from class: LeafReader

Optional method: Return a IndexReader.CacheHelper that can be used to cache based on the content of this leaf regardless of deletions. Two readers that have the same data but different sets of deleted documents or doc values updates may be considered equal. Consider using IndexReader.getReaderCacheHelper() if you need deletions or dv updates to be taken into account.

A return value of null indicates that this reader is not suited for caching, which is typically the case for short-lived wrappers that alter the content of the wrapped leaf reader.

Specified by:

getCoreCacheHelper in class LeafReader

getReaderCacheHelper

public IndexReader.CacheHelper getReaderCacheHelper()

Description copied from class: IndexReader

Optional method: Return a IndexReader.CacheHelper that can be used to cache based on the content of this reader. Two readers that have different data or different sets of deleted documents will be considered different.

A return value of null indicates that this reader is not suited for caching, which is typically the case for short-lived wrappers that alter the content of the wrapped reader.

Specified by:

getReaderCacheHelper in class IndexReader

getTermVectors

public Fields getTermVectors(int docID)
                      throws IOException

Description copied from class: IndexReader

Retrieve term vectors for this document, or null if term vectors were not indexed. The returned Fields instance acts like a single-document inverted index (the docID will be 0).

Specified by:

getTermVectors in class IndexReader

Throws:

IOException

doClose

protected void doClose()
                throws IOException

Description copied from class: IndexReader

Implements close.

Specified by:

doClose in class IndexReader

Throws:

IOException

getNumericDocValues

public NumericDocValues getNumericDocValues(String field)
                                     throws IOException

Description copied from class: LeafReader

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

Specified by:

getNumericDocValues in class LeafReader

Throws:

IOException

getBinaryDocValues

public BinaryDocValues getBinaryDocValues(String field)
                                   throws IOException

Description copied from class: LeafReader

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

Specified by:

getBinaryDocValues in class LeafReader

Throws:

IOException

getSortedDocValues

public SortedDocValues getSortedDocValues(String field)
                                   throws IOException

Description copied from class: LeafReader

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.

Specified by:

getSortedDocValues in class LeafReader

Throws:

IOException

getSortedNumericDocValues

public SortedNumericDocValues getSortedNumericDocValues(String field)
                                                 throws IOException

Description copied from class: LeafReader

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

Specified by:

getSortedNumericDocValues in class LeafReader

Throws:

IOException

getSortedSetDocValues

public SortedSetDocValues getSortedSetDocValues(String field)
                                         throws IOException

Description copied from class: LeafReader

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.

Specified by:

getSortedSetDocValues in class LeafReader

Throws:

IOException

getNormValues

public NumericDocValues getNormValues(String field)
                               throws IOException

Description copied from class: LeafReader

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.

Specified by:

getNormValues in class LeafReader

Throws:

IOException

getPointValues

public PointValues getPointValues(String fieldName)
                           throws IOException

Description copied from class: LeafReader

Returns the PointValues used for numeric or spatial searches for the given field, or null if there are no point fields.

Specified by:

getPointValues in class LeafReader

Throws:

IOException

getVectorValues

public VectorValues getVectorValues(String fieldName)
                             throws IOException

Description copied from class: LeafReader

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

Specified by:

getVectorValues in class LeafReader

Throws:

IOException

searchNearestVectors

public TopDocs searchNearestVectors(String fieldName,
                                    float[] target,
                                    int k,
                                    Bits acceptDocs)
                             throws IOException

Description copied from class: LeafReader

Return the k nearest neighbor documents as determined by comparison of their vector values for this field, to the given vector, by the field's search strategy. If the search strategy is reversed, lower values indicate nearer vectors, otherwise higher scores indicate nearer vectors. Unlike relevance scores, vector scores may be negative.

Specified by:

searchNearestVectors in class LeafReader

Parameters:

fieldName - the vector field to search

target - the vector-valued query

k - the number of docs to return

acceptDocs - Bits that represents the allowed documents to match, or null if they are all allowed to match.

Returns:

the k nearest neighbor documents, along with their (searchStrategy-specific) scores.

Throws:

IOException

checkIntegrity

public void checkIntegrity()
                    throws IOException

Description copied from class: LeafReader

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.

Specified by:

checkIntegrity in class LeafReader

Throws:

IOException

getParallelReaders

public LeafReader[] getParallelReaders()

Returns the LeafReaders that were passed on init.

getMetaData

public LeafMetaData getMetaData()

Description copied from class: LeafReader

Return metadata about this leaf.

Specified by:

getMetaData in class LeafReader