org.apache.lucene.search.join

## Class ToChildBlockJoinQuery

- java.lang.Object
- - org.apache.lucene.search.Query
  - - org.apache.lucene.search.join.ToChildBlockJoinQuery

-     public class ToChildBlockJoinQuery
      extends Query

  Just like `ToParentBlockJoinQuery`, except this query joins in reverse: you provide a Query matching parent documents and it joins down to child documents.
  WARNING: This API is experimental and might change in incompatible ways in the next release.

- - ### Constructor Summary

    Constructors
    Constructor and Description
    `ToChildBlockJoinQuery(Query parentQuery, BitSetProducer parentsFilter)` Create a ToChildBlockJoinQuery.

  - ### Method Summary

    All Methods Instance Methods Concrete Methods
    Modifier and Type | Method and Description
    --- | ---
    `Weight` | `createWeight(IndexSearcher searcher, boolean needsScores, float boost)`
    `boolean` | `equals(Object other)`
    `Query` | `getParentQuery()` Return our parent query.
    `int` | `hashCode()`
    `Query` | `rewrite(IndexReader reader)`
    `String` | `toString(String field)`

    - ### Methods inherited from class org.apache.lucene.search.Query

      `classHash, sameClassAs, toString`

    - ### Methods inherited from class java.lang.Object

      `clone, finalize, getClass, notify, notifyAll, wait, wait, wait`

- - ### Constructor Detail

    - #### ToChildBlockJoinQuery

          public ToChildBlockJoinQuery(Query parentQuery,
                                       BitSetProducer parentsFilter)

      Create a ToChildBlockJoinQuery.
      Parameters:
        `parentQuery` - Query that matches parent documents
        `parentsFilter` - Filter identifying the parent documents.

  - ### Method Detail

    - #### createWeight

          public Weight createWeight(IndexSearcher searcher,
                                     boolean needsScores,
                                     float boost)
                              throws IOException

      Overrides:
        `createWeight` in class `Query`
      Throws:
        `IOException`

    - #### getParentQuery

          public Query getParentQuery()

      Return our parent query.

    - #### rewrite

          public Query rewrite(IndexReader reader)
                        throws IOException

      Overrides:
        `rewrite` in class `Query`
      Throws:
        `IOException`

    - #### toString

          public String toString(String field)

      Specified by:
        `toString` in class `Query`

    - #### equals

          public boolean equals(Object other)

      Specified by:
        `equals` in class `Query`

    - #### hashCode

          public int hashCode()

      Specified by:
        `hashCode` in class `Query`

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