## Uses of Class
org.apache.lucene.search.CollectionStatistics

- Packages that use CollectionStatistics
  Package | Description
  --- | ---
  org.apache.lucene.search | Code to search indices.
  org.apache.lucene.search.similarities | This package contains the various ranking models that can be used in Lucene.

- - ### Uses of CollectionStatistics in org.apache.lucene.search

    Methods in org.apache.lucene.search that return CollectionStatistics
    Modifier and Type | Method | Description
    --- | --- | ---
    `CollectionStatistics` | IndexSearcher.`collectionStatistics​(String field)` | Returns `CollectionStatistics` for a field, or `null` if the field does not exist (has no indexed terms)

  - ### Uses of CollectionStatistics in org.apache.lucene.search.similarities

    Methods in org.apache.lucene.search.similarities with parameters of type CollectionStatistics
    Modifier and Type | Method | Description
    --- | --- | ---
    `protected float` | BM25Similarity.`avgFieldLength​(CollectionStatistics collectionStats)` | The default implementation computes the average as `sumTotalTermFreq / docCount`
    `protected void` | LMSimilarity.`fillBasicStats​(BasicStats stats, CollectionStatistics collectionStats, TermStatistics termStats)` | Computes the collection probability of the current term in addition to the usual statistics.
    `protected void` | SimilarityBase.`fillBasicStats​(BasicStats stats, CollectionStatistics collectionStats, TermStatistics termStats)` | Fills all member fields defined in `BasicStats` in `stats`.
    `Explanation` | BM25Similarity.`idfExplain​(CollectionStatistics collectionStats, TermStatistics termStats)` | Computes a score factor for a simple term and returns an explanation for that score factor.
    `Explanation` | BM25Similarity.`idfExplain​(CollectionStatistics collectionStats, TermStatistics[] termStats)` | Computes a score factor for a phrase.
    `Explanation` | ClassicSimilarity.`idfExplain​(CollectionStatistics collectionStats, TermStatistics termStats)` |
    `Explanation` | TFIDFSimilarity.`idfExplain​(CollectionStatistics collectionStats, TermStatistics termStats)` | Computes a score factor for a simple term and returns an explanation for that score factor.
    `Explanation` | TFIDFSimilarity.`idfExplain​(CollectionStatistics collectionStats, TermStatistics[] termStats)` | Computes a score factor for a phrase.
    `Similarity.SimScorer` | BM25Similarity.`scorer​(float boost, CollectionStatistics collectionStats, TermStatistics... termStats)` |
    `Similarity.SimScorer` | BooleanSimilarity.`scorer​(float boost, CollectionStatistics collectionStats, TermStatistics... termStats)` |
    `Similarity.SimScorer` | MultiSimilarity.`scorer​(float boost, CollectionStatistics collectionStats, TermStatistics... termStats)` |
    `Similarity.SimScorer` | PerFieldSimilarityWrapper.`scorer​(float boost, CollectionStatistics collectionStats, TermStatistics... termStats)` |
    `abstract Similarity.SimScorer` | Similarity.`scorer​(float boost, CollectionStatistics collectionStats, TermStatistics... termStats)` | Compute any collection-level weight (e.g.
    `Similarity.SimScorer` | SimilarityBase.`scorer​(float boost, CollectionStatistics collectionStats, TermStatistics... termStats)` |
    `Similarity.SimScorer` | TFIDFSimilarity.`scorer​(float boost, CollectionStatistics collectionStats, TermStatistics... termStats)` |