org.apache.lucene.index

Class ParallelAtomicReader

java.lang.Object

org.apache.lucene.index.IndexReader

org.apache.lucene.index.AtomicReader

org.apache.lucene.index.ParallelAtomicReader

All Implemented Interfaces:

Closeable

public final class ParallelAtomicReader
extends AtomicReader

An AtomicReader 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.ReaderClosedListener

Constructor Summary

Constructors

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

Method Summary

Methods

Modifier and Type	Method and Description
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.
DocValues	docValues(String field) Returns DocValues for this field.
Fields	fields() Returns Fields for this reader.
FieldInfos	getFieldInfos() Get the FieldInfos describing all fields in this reader.
Bits	getLiveDocs() Returns the Bits representing live (not deleted) docs.
Fields	getTermVectors(int docID) Retrieve term vectors for this document, or null if term vectors were not indexed.
boolean	hasDeletions() Returns true if any documents have been deleted
int	maxDoc() Returns one greater than the largest possible document number.
DocValues	normValues(String field) Returns DocValues for this field's normalization values.
int	numDocs() Returns the number of documents in this index.
String	toString()

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

docFreq, getContext, hasNorms, termDocsEnum, termPositionsEnum, terms, totalTermFreq

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

addReaderClosedListener, close, decRef, document, document, ensureOpen, equals, getCombinedCoreAndDeletesKey, getCoreCacheKey, getRefCount, getTermVector, hashCode, incRef, leaves, numDeletedDocs, open, open, open, open, open, registerParentReader, removeReaderClosedListener, tryIncRef

Methods inherited from class java.lang.Object

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

Constructor Detail

ParallelAtomicReader

public ParallelAtomicReader(AtomicReader... readers)
                     throws IOException

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

Throws:

IOException

ParallelAtomicReader

public ParallelAtomicReader(boolean closeSubReaders,
                    AtomicReader... readers)
                     throws IOException

Create a ParallelAtomicReader based on the provided readers.

Throws:

IOException

ParallelAtomicReader

public ParallelAtomicReader(boolean closeSubReaders,
                    AtomicReader[] readers,
                    AtomicReader[] storedFieldsReaders)
                     throws IOException

Expert: create a ParallelAtomicReader 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: 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 AtomicReader

getLiveDocs

public Bits getLiveDocs()

Description copied from class: AtomicReader

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 AtomicReader

fields

public Fields fields()

Description copied from class: AtomicReader

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

Specified by:

fields in class AtomicReader

numDocs

public int numDocs()

Description copied from class: IndexReader

Returns the number of documents in this index.

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

hasDeletions

public boolean hasDeletions()

Description copied from class: IndexReader

Returns true if any documents have been deleted

Specified by:

hasDeletions 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

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

docValues

public DocValues docValues(String field)
                    throws IOException

Description copied from class: AtomicReader

Returns DocValues for this field. This method may return null if the reader has no per-document values stored.

Specified by:

docValues in class AtomicReader

Throws:

IOException

normValues

public DocValues normValues(String field)
                     throws IOException

Description copied from class: AtomicReader

Returns DocValues for this field's normalization values. This method may return null if the field has no norms.

Specified by:

normValues in class AtomicReader

Throws:

IOException