Package org.apache.lucene.index
Class NoMergePolicy
- java.lang.Object
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- org.apache.lucene.index.MergePolicy
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- org.apache.lucene.index.NoMergePolicy
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- All Implemented Interfaces:
Closeable
,AutoCloseable
public final class NoMergePolicy extends MergePolicy
AMergePolicy
which never returns merges to execute (hence it's name). It is also a singleton and can be accessed throughNO_COMPOUND_FILES
if you want to indicate the index does not use compound files, or throughCOMPOUND_FILES
otherwise. Use it if you want to prevent anIndexWriter
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.
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Nested Class Summary
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Nested classes/interfaces inherited from class org.apache.lucene.index.MergePolicy
MergePolicy.MergeAbortedException, MergePolicy.MergeException, MergePolicy.MergeSpecification, MergePolicy.OneMerge
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Field Summary
Fields Modifier and Type Field Description static MergePolicy
COMPOUND_FILES
A singletonNoMergePolicy
which indicates the index uses compound files.static MergePolicy
NO_COMPOUND_FILES
A singletonNoMergePolicy
which indicates the index does not use compound files.-
Fields inherited from class org.apache.lucene.index.MergePolicy
writer
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Method Summary
All Methods Instance Methods Concrete Methods Modifier and Type Method Description void
close()
Release all resources for the policy.MergePolicy.MergeSpecification
findForcedDeletesMerges(SegmentInfos segmentInfos)
Determine what set of merge operations is necessary in order to expunge all deletes from the index.MergePolicy.MergeSpecification
findForcedMerges(SegmentInfos segmentInfos, int maxSegmentCount, Map<SegmentInfo,Boolean> segmentsToMerge)
Determine what set of merge operations is necessary in order to merge to <= the specified segment count.MergePolicy.MergeSpecification
findMerges(SegmentInfos segmentInfos)
Determine what set of merge operations are now necessary on the index.void
setIndexWriter(IndexWriter writer)
Sets theIndexWriter
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.
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Field Detail
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NO_COMPOUND_FILES
public static final MergePolicy NO_COMPOUND_FILES
A singletonNoMergePolicy
which indicates the index does not use compound files.
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COMPOUND_FILES
public static final MergePolicy COMPOUND_FILES
A singletonNoMergePolicy
which indicates the index uses compound files.
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Method Detail
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close
public void close()
Description copied from class:MergePolicy
Release all resources for the policy.- Specified by:
close
in interfaceAutoCloseable
- Specified by:
close
in interfaceCloseable
- Specified by:
close
in classMergePolicy
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findMerges
public MergePolicy.MergeSpecification findMerges(SegmentInfos segmentInfos) throws CorruptIndexException, IOException
Description copied from class:MergePolicy
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 theIndexWriter
instance so only one thread at a time will call this method.- Specified by:
findMerges
in classMergePolicy
- Parameters:
segmentInfos
- the total set of segments in the index- Throws:
CorruptIndexException
IOException
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findForcedMerges
public MergePolicy.MergeSpecification findForcedMerges(SegmentInfos segmentInfos, int maxSegmentCount, Map<SegmentInfo,Boolean> segmentsToMerge) throws CorruptIndexException, IOException
Description copied from class:MergePolicy
Determine what set of merge operations is necessary in order to merge to <= the specified segment count.IndexWriter
calls this when itsIndexWriter.forceMerge(int)
method is called. This call is always synchronized on theIndexWriter
instance so only one thread at a time will call this method.- Specified by:
findForcedMerges
in classMergePolicy
- Parameters:
segmentInfos
- the total set of segments in the indexmaxSegmentCount
- requested maximum number of segments in the index (currently this is always 1)segmentsToMerge
- contains the specific SegmentInfo instances that must be merged away. This may be a subset of all SegmentInfos. If the value is True for a given SegmentInfo, that means this segment was an original segment present in the to-be-merged index; else, it was a segment produced by a cascaded merge.- Throws:
CorruptIndexException
IOException
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findForcedDeletesMerges
public MergePolicy.MergeSpecification findForcedDeletesMerges(SegmentInfos segmentInfos) throws CorruptIndexException, IOException
Description copied from class:MergePolicy
Determine what set of merge operations is necessary in order to expunge all deletes from the index.- Specified by:
findForcedDeletesMerges
in classMergePolicy
- Parameters:
segmentInfos
- the total set of segments in the index- Throws:
CorruptIndexException
IOException
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useCompoundFile
public boolean useCompoundFile(SegmentInfos segments, SegmentInfo newSegment)
Description copied from class:MergePolicy
Returns true if a new segment (regardless of its origin) should use the compound file format.- Specified by:
useCompoundFile
in classMergePolicy
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setIndexWriter
public void setIndexWriter(IndexWriter writer)
Description copied from class:MergePolicy
Sets theIndexWriter
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.- Overrides:
setIndexWriter
in classMergePolicy
- See Also:
SetOnce
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