# Package org.apache.lucene.codecs.blocktree

BlockTree terms dictionary.

See: Description

- Class Summary
  Class | Description
  --- | ---
  BlockTreeTermsReader | A block-based terms index and dictionary that assigns terms to variable length blocks according to how they share prefixes.
  BlockTreeTermsWriter | Block-based terms index and dictionary writer.
  FieldReader | BlockTree's implementation of `Terms`.
  Stats | BlockTree statistics for a single field returned by `FieldReader.getStats()`.

- Enum Summary
  Enum | Description
  --- | ---
  BlockTreeTermsReader.FSTLoadMode | An enum that allows to control if term index FSTs are loaded into memory or read off-heap

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

BlockTree terms dictionary.

This terms dictionary organizes all terms into blocks according to shared prefix, such that each block has enough terms, and then stores the prefix trie in memory as an FST as the index structure. It allows you to plug in your own `PostingsWriterBase` to implement the postings.

See `BlockTreeTermsWriter` for the file format.

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