org.apache.lucene.index

Class StandardDirectoryReader

java.lang.Object

org.apache.lucene.index.IndexReader

org.apache.lucene.index.CompositeReader

org.apache.lucene.index.BaseCompositeReader<LeafReader>

org.apache.lucene.index.DirectoryReader

org.apache.lucene.index.StandardDirectoryReader

All Implemented Interfaces:

Closeable, AutoCloseable

public final class StandardDirectoryReader
extends DirectoryReader

Default implementation of DirectoryReader.

Nested Class Summary

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

IndexReader.CacheHelper, IndexReader.CacheKey, IndexReader.ClosedListener

Field Summary

Fields inherited from class org.apache.lucene.index.DirectoryReader

directory

Method Summary

Modifier and Type	Method and Description
protected void	doClose() Implements close.
protected DirectoryReader	doOpenIfChanged() Implement this method to support DirectoryReader.openIfChanged(DirectoryReader).
protected DirectoryReader	doOpenIfChanged(IndexCommit commit) Implement this method to support DirectoryReader.openIfChanged(DirectoryReader,IndexCommit).
protected DirectoryReader	doOpenIfChanged(IndexWriter writer, boolean applyAllDeletes) Implement this method to support DirectoryReader.openIfChanged(DirectoryReader,IndexWriter,boolean).
IndexCommit	getIndexCommit() Expert: return the IndexCommit that this reader has opened.
IndexReader.CacheHelper	getReaderCacheHelper() Optional method: Return a IndexReader.CacheHelper that can be used to cache based on the content of this reader.
SegmentInfos	getSegmentInfos() Return the SegmentInfos for this reader.
long	getVersion() Version number when this IndexReader was opened.
boolean	isCurrent() Check whether any new changes have occurred to the index since this reader was opened.
static DirectoryReader	open(Directory directory, SegmentInfos infos, List<? extends LeafReader> oldReaders) This constructor is only used for doOpenIfChanged(SegmentInfos), as well as NRT replication.
String	toString()

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

directory, indexExists, listCommits, open, open, open, open, openIfChanged, openIfChanged, openIfChanged, openIfChanged

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

docFreq, document, getDocCount, getSequentialSubReaders, getSumDocFreq, getSumTotalTermFreq, getTermVectors, maxDoc, numDocs, readerBase, readerIndex, totalTermFreq

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

getContext

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

Method Detail

open

public static DirectoryReader open(Directory directory,
                                   SegmentInfos infos,
                                   List<? extends LeafReader> oldReaders)
                            throws IOException

This constructor is only used for doOpenIfChanged(SegmentInfos), as well as NRT replication.

Throws:

IOException

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

toString

public String toString()

Overrides:

toString in class CompositeReader

doOpenIfChanged

protected DirectoryReader doOpenIfChanged()
                                   throws IOException

Description copied from class: DirectoryReader

Implement this method to support DirectoryReader.openIfChanged(DirectoryReader). If this reader does not support reopen, return null, so client code is happy. This should be consistent with DirectoryReader.isCurrent() (should always return true) if reopen is not supported.

Specified by:

doOpenIfChanged in class DirectoryReader

Returns:

null if there are no changes; else, a new DirectoryReader instance.

Throws:

IOException - if there is a low-level IO error

doOpenIfChanged

protected DirectoryReader doOpenIfChanged(IndexCommit commit)
                                   throws IOException

Description copied from class: DirectoryReader

Implement this method to support DirectoryReader.openIfChanged(DirectoryReader,IndexCommit). If this reader does not support reopen from a specific IndexCommit, throw UnsupportedOperationException.

Specified by:

doOpenIfChanged in class DirectoryReader

Returns:

null if there are no changes; else, a new DirectoryReader instance.

Throws:

IOException - if there is a low-level IO error

doOpenIfChanged

protected DirectoryReader doOpenIfChanged(IndexWriter writer,
                                          boolean applyAllDeletes)
                                   throws IOException

Description copied from class: DirectoryReader

Implement this method to support DirectoryReader.openIfChanged(DirectoryReader,IndexWriter,boolean). If this reader does not support reopen from IndexWriter, throw UnsupportedOperationException.

Specified by:

doOpenIfChanged in class DirectoryReader

Returns:

null if there are no changes; else, a new DirectoryReader instance.

Throws:

IOException - if there is a low-level IO error

getVersion

public long getVersion()

Description copied from class: DirectoryReader

Version number when this IndexReader was opened.

This method returns the version recorded in the commit that the reader opened. This version is advanced every time a change is made with IndexWriter.

Specified by:

getVersion in class DirectoryReader

getSegmentInfos

public SegmentInfos getSegmentInfos()

Return the SegmentInfos for this reader.

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

isCurrent

public boolean isCurrent()
                  throws IOException

Description copied from class: DirectoryReader

Check whether any new changes have occurred to the index since this reader was opened.

If this reader was created by calling DirectoryReader.open(org.apache.lucene.store.Directory), then this method checks if any further commits (see IndexWriter.commit()) have occurred in the directory.

If instead this reader is a near real-time reader (ie, obtained by a call to DirectoryReader.open(IndexWriter), or by calling DirectoryReader.openIfChanged(org.apache.lucene.index.DirectoryReader) on a near real-time reader), then this method checks if either a new commit has occurred, or any new uncommitted changes have taken place via the writer. Note that even if the writer has only performed merging, this method will still return false.

In any event, if this returns false, you should call DirectoryReader.openIfChanged(org.apache.lucene.index.DirectoryReader) to get a new reader that sees the changes.

Specified by:

isCurrent in class DirectoryReader

Throws:

IOException - if there is a low-level IO error

doClose

protected void doClose()
                throws IOException

Description copied from class: IndexReader

Implements close.

Specified by:

doClose in class IndexReader

Throws:

IOException

getIndexCommit

public IndexCommit getIndexCommit()
                           throws IOException

Description copied from class: DirectoryReader

Expert: return the IndexCommit that this reader has opened.

Specified by:

getIndexCommit in class DirectoryReader

Throws:

IOException

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