# Package org.apache.lucene.codecs.blockterms

Pluggable term index / block terms dictionary implementations.

See: Description

- Class Summary
  Class | Description
  --- | ---
  BlockTermsReader | Handles a terms dict, but decouples all details of doc/freqs/positions reading to an instance of `PostingsReaderBase`.
  BlockTermsWriter | Writes terms dict, block-encoding (column stride) each term's metadata for each set of terms between two index terms.
  FixedGapTermsIndexReader | TermsIndexReader for simple every Nth terms indexes.
  FixedGapTermsIndexWriter | Selects every Nth term as and index term, and hold term bytes (mostly) fully expanded in memory.
  TermsIndexReaderBase | `BlockTermsReader` interacts with an instance of this class to manage its terms index.
  TermsIndexReaderBase.FieldIndexEnum | Similar to TermsEnum, except, the only "metadata" it reports for a given indexed term is the long fileOffset into the main terms dictionary file.
  TermsIndexWriterBase | Base class for terms index implementations to plug into `BlockTermsWriter`.
  VariableGapTermsIndexReader | See `VariableGapTermsIndexWriter`
  VariableGapTermsIndexWriter | Selects index terms according to provided pluggable `VariableGapTermsIndexWriter.IndexTermSelector`, and stores them in a prefix trie that's loaded entirely in RAM stored as an FST.
  VariableGapTermsIndexWriter.EveryNOrDocFreqTermSelector | Sets an index term when docFreq >= docFreqThresh, or every interval terms.
  VariableGapTermsIndexWriter.EveryNTermSelector | Same policy as `FixedGapTermsIndexWriter`
  VariableGapTermsIndexWriter.IndexTermSelector | Hook for selecting which terms should be placed in the terms index.

## Package org.apache.lucene.codecs.blockterms Description

Pluggable term index / block terms dictionary implementations.

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