Class PerFieldPostingsFormat
- java.lang.Object
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- org.apache.lucene.codecs.PostingsFormat
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- org.apache.lucene.codecs.perfield.PerFieldPostingsFormat
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- All Implemented Interfaces:
NamedSPILoader.NamedSPI
public abstract class PerFieldPostingsFormat extends PostingsFormat
Enables per field postings support.Note, when extending this class, the name (
PostingsFormat.getName()) is written into the index. In order for the field to be read, the name must resolve to your implementation viaPostingsFormat.forName(String). This method uses Java'sService Provider Interfaceto resolve format names.Files written by each posting format have an additional suffix containing the format name. For example, in a per-field configuration instead of
_1.prxfilenames would look like_1_Lucene40_0.prx.- See Also:
ServiceLoader- WARNING: This API is experimental and might change in incompatible ways in the next release.
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Field Summary
Fields Modifier and Type Field Description static StringPER_FIELD_FORMAT_KEYFieldInfoattribute name used to store the format name for each field.static StringPER_FIELD_NAMEName of thisPostingsFormat.static StringPER_FIELD_SUFFIX_KEYFieldInfoattribute name used to store the segment suffix name for each field.-
Fields inherited from class org.apache.lucene.codecs.PostingsFormat
EMPTY
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Constructor Summary
Constructors Modifier Constructor Description protectedPerFieldPostingsFormat()Sole constructor.
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Method Summary
All Methods Instance Methods Abstract Methods Concrete Methods Modifier and Type Method Description FieldsConsumerfieldsConsumer(SegmentWriteState state)Writes a new segmentFieldsProducerfieldsProducer(SegmentReadState state)Reads a segment.abstract PostingsFormatgetPostingsFormatForField(String field)Returns the postings format that should be used for writing new segments offield.-
Methods inherited from class org.apache.lucene.codecs.PostingsFormat
availablePostingsFormats, forName, getName, reloadPostingsFormats, toString
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Field Detail
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PER_FIELD_NAME
public static final String PER_FIELD_NAME
Name of thisPostingsFormat.- See Also:
- Constant Field Values
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PER_FIELD_FORMAT_KEY
public static final String PER_FIELD_FORMAT_KEY
FieldInfoattribute name used to store the format name for each field.
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Method Detail
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fieldsConsumer
public final FieldsConsumer fieldsConsumer(SegmentWriteState state) throws IOException
Description copied from class:PostingsFormatWrites a new segment- Specified by:
fieldsConsumerin classPostingsFormat- Throws:
IOException
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fieldsProducer
public final FieldsProducer fieldsProducer(SegmentReadState state) throws IOException
Description copied from class:PostingsFormatReads a segment. NOTE: by the time this call returns, it must hold open any files it will need to use; else, those files may be deleted. Additionally, required files may be deleted during the execution of this call before there is a chance to open them. Under these circumstances an IOException should be thrown by the implementation. IOExceptions are expected and will automatically cause a retry of the segment opening logic with the newly revised segments.- Specified by:
fieldsProducerin classPostingsFormat- Throws:
IOException
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getPostingsFormatForField
public abstract PostingsFormat getPostingsFormatForField(String field)
Returns the postings format that should be used for writing new segments offield.The field to format mapping is written to the index, so this method is only invoked when writing, not when reading.
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