ParallelLeafReader (Lucene 8.9.0 API)乐学网一站式学习平台

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 and 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

All Methods Instance Methods Concrete Methods
Modifier and Type	Method and 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 `LeafReader`s 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.
`int`	`maxDoc()` Returns one greater than the largest possible document number.
`int`	`numDocs()` Returns the number of documents in this index.
`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
  - 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

Class ParallelLeafReader

Nested Class Summary

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

Constructor Summary

Method Summary

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

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

Methods inherited from class java.lang.Object

Constructor Detail

ParallelLeafReader

ParallelLeafReader

ParallelLeafReader

Method Detail

toString

getFieldInfos

getLiveDocs

terms

numDocs

maxDoc

document

getCoreCacheHelper

getReaderCacheHelper

getTermVectors

doClose

getNumericDocValues

getBinaryDocValues

getSortedDocValues

getSortedNumericDocValues

getSortedSetDocValues

getNormValues

getPointValues

checkIntegrity

getParallelReaders

getMetaData