public final class

NoMergePolicy

extends MergePolicy
java.lang.Object
   ↳ org.apache.lucene.index.MergePolicy
     ↳ org.apache.lucene.index.NoMergePolicy

Class Overview

A MergePolicy which never returns merges to execute (hence it's name). It is also a singleton and can be accessed through NO_COMPOUND_FILES if you want to indicate the index does not use compound files, or through COMPOUND_FILES otherwise. Use it if you want to prevent an IndexWriter from ever executing merges, without going through the hassle of tweaking a merge policy's settings to achieve that, such as changing its merge factor.

Summary

Fields
public static final MergePolicy COMPOUND_FILES A singleton NoMergePolicy which indicates the index uses compound files.
public static final MergePolicy NO_COMPOUND_FILES A singleton NoMergePolicy which indicates the index does not use compound files.
[Expand]
Inherited Fields
From class org.apache.lucene.index.MergePolicy
Public Methods
void close()
Release all resources for the policy.
MergePolicy.MergeSpecification findMerges(SegmentInfos segmentInfos)
Determine what set of merge operations are now necessary on the index.
MergePolicy.MergeSpecification findMergesForOptimize(SegmentInfos segmentInfos, int maxSegmentCount, Set<SegmentInfo> segmentsToOptimize)
Determine what set of merge operations is necessary in order to optimize the index.
MergePolicy.MergeSpecification findMergesToExpungeDeletes(SegmentInfos segmentInfos)
Determine what set of merge operations is necessary in order to expunge all deletes from the index.
void setIndexWriter(IndexWriter writer)
Sets the IndexWriter to use by this merge policy.
String toString()
boolean useCompoundFile(SegmentInfos segments, SegmentInfo newSegment)
Returns true if a new segment (regardless of its origin) should use the compound file format.
[Expand]
Inherited Methods
From class org.apache.lucene.index.MergePolicy
From class java.lang.Object
From interface java.io.Closeable

Fields

public static final MergePolicy COMPOUND_FILES

A singleton NoMergePolicy which indicates the index uses compound files.

public static final MergePolicy NO_COMPOUND_FILES

A singleton NoMergePolicy which indicates the index does not use compound files.

Public Methods

public void close ()

Release all resources for the policy.

public MergePolicy.MergeSpecification findMerges (SegmentInfos segmentInfos)

Determine what set of merge operations are now necessary on the index. IndexWriter calls this whenever there is a change to the segments. This call is always synchronized on the IndexWriter instance so only one thread at a time will call this method.

Parameters
segmentInfos the total set of segments in the index
Throws
CorruptIndexException
IOException

public MergePolicy.MergeSpecification findMergesForOptimize (SegmentInfos segmentInfos, int maxSegmentCount, Set<SegmentInfo> segmentsToOptimize)

Determine what set of merge operations is necessary in order to optimize the index. IndexWriter calls this when its optimize() method is called. This call is always synchronized on the IndexWriter instance so only one thread at a time will call this method.

Parameters
segmentInfos the total set of segments in the index
maxSegmentCount requested maximum number of segments in the index (currently this is always 1)
segmentsToOptimize contains the specific SegmentInfo instances that must be merged away. This may be a subset of all SegmentInfos.
Throws
CorruptIndexException
IOException

public MergePolicy.MergeSpecification findMergesToExpungeDeletes (SegmentInfos segmentInfos)

Determine what set of merge operations is necessary in order to expunge all deletes from the index.

Parameters
segmentInfos the total set of segments in the index
Throws
CorruptIndexException
IOException

public void setIndexWriter (IndexWriter writer)

Sets the IndexWriter to use by this merge policy. This method is allowed to be called only once, and is usually set by IndexWriter. If it is called more than once, SetOnce.AlreadySetException is thrown.

public String toString ()

public boolean useCompoundFile (SegmentInfos segments, SegmentInfo newSegment)

Returns true if a new segment (regardless of its origin) should use the compound file format.