Package org.apache.lucene.codecs

Codecs API: API for customization of the encoding and structure of the index.

See: Description

Class Summary

Class	Description
BlockTermState	Holds all state required for PostingsReaderBase to produce a DocsEnum without re-seeking the terms dict.
BlockTreeTermsReader	A block-based terms index and dictionary that assigns terms to variable length blocks according to how they share prefixes.
BlockTreeTermsReader.Stats	BlockTree statistics for a single field returned by BlockTreeTermsReader.FieldReader.computeStats().
BlockTreeTermsWriter	Block-based terms index and dictionary writer.
Codec	Encodes/decodes an inverted index segment.
CodecUtil	Utility class for reading and writing versioned headers.
DocValuesArraySource	DocValues DocValues.Source implementation backed by simple arrays.
DocValuesConsumer	Abstract API that consumes IndexableFields.
DocValuesFormat	Encodes/decodes DocValues
FieldInfosFormat	Encodes/decodes FieldInfos
FieldInfosReader	Codec API for reading FieldInfos.
FieldInfosWriter	Codec API for writing FieldInfos.
FieldsConsumer	Abstract API that consumes terms, doc, freq, prox, offset and payloads postings.
FieldsProducer	Abstract API that produces terms, doc, freq, prox, offset and payloads postings.
FilterCodec	A codec that forwards all its method calls to another codec.
LiveDocsFormat	Format for live/deleted documents
MappingMultiDocsAndPositionsEnum	Exposes flex API, merged from flex API of sub-segments, remapping docIDs (this is used for segment merging).
MappingMultiDocsEnum	Exposes flex API, merged from flex API of sub-segments, remapping docIDs (this is used for segment merging).
MultiLevelSkipListReader	This abstract class reads skip lists with multiple levels.
MultiLevelSkipListWriter	This abstract class writes skip lists with multiple levels.
NormsFormat	format for normalization factors
PerDocConsumer	Abstract API that consumes per document values.
PerDocProducer	Abstract API that provides access to one or more per-document storage features.
PerDocProducerBase	Abstract base class for PerDocProducer implementations
PostingsBaseFormat	Provides a PostingsReaderBase and PostingsWriterBase.
PostingsConsumer	Abstract API that consumes postings for an individual term.
PostingsFormat	Encodes/decodes terms, postings, and proximity data.
PostingsReaderBase	The core terms dictionaries (BlockTermsReader, BlockTreeTermsReader) interact with a single instance of this class to manage creation of DocsEnum and DocsAndPositionsEnum instances.
PostingsWriterBase	Extension of PostingsConsumer to support pluggable term dictionaries.
SegmentInfoFormat	Expert: Controls the format of the SegmentInfo (segment metadata file).
SegmentInfoReader	Specifies an API for classes that can read SegmentInfo information.
SegmentInfoWriter	Specifies an API for classes that can write out SegmentInfo data.
StoredFieldsFormat	Controls the format of stored fields
StoredFieldsReader	Codec API for reading stored fields.
StoredFieldsWriter	Codec API for writing stored fields:
TermsConsumer	Abstract API that consumes terms for an individual field.
TermStats	Holder for per-term statistics.
TermVectorsFormat	Controls the format of term vectors
TermVectorsReader	Codec API for reading term vectors:
TermVectorsWriter	Codec API for writing term vectors:

Package org.apache.lucene.codecs Description

Codecs API: API for customization of the encoding and structure of the index.

The Codec API allows you to customise the way the following pieces of index information are stored:

• Postings lists - see PostingsFormat
• DocValues - see DocValuesFormat
• Stored fields - see StoredFieldsFormat
• Term vectors - see TermVectorsFormat
• FieldInfos - see FieldInfosFormat
• SegmentInfo - see SegmentInfoFormat
• Norms - see NormsFormat
• Live documents - see LiveDocsFormat

For some concrete implementations beyond Lucene's official index format, see the Codecs module.

Codecs are identified by name through the Java Service Provider Interface. To create your own codec, extend Codec and pass the new codec's name to the super() constructor:

public class MyCodec extends Codec {

    public MyCodec() {
        super("MyCodecName");
    }

    ...
}

You will need to register the Codec class so that the ServiceLoader can find it, by including a META-INF/services/org.apache.lucene.codecs.Codec file on your classpath that contains the package-qualified name of your codec.

If you just want to customise the PostingsFormat, or use different postings formats for different fields, then you can register your custom postings format in the same way (in META-INF/services/org.apache.lucene.codecs.PostingsFormat), and then extend the default Lucene40Codec and override Lucene40Codec.getPostingsFormatForField(String) to return your custom postings format.