# Package org.apache.lucene.codecs.lucene90.blocktree

package org.apache.lucene.codecs.lucene90.blocktree
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 `Lucene90BlockTreeTermsWriter` for the file format.

Related Packages
Package
Description
org.apache.lucene.codecs.lucene90
Lucene 9.0 file format.
org.apache.lucene.codecs.lucene90.compressing
Lucene 9.0 compressing format.
Classes
Class
Description
FieldReader
BlockTree's implementation of `Terms`.
Lucene90BlockTreeTermsReader
A block-based terms index and dictionary that assigns terms to variable length blocks according to how they share prefixes.
Lucene90BlockTreeTermsWriter
Block-based terms index and dictionary writer.
Stats
BlockTree statistics for a single field returned by `FieldReader.getStats()`.