org.apache.lucene.search

## Class NormsFieldExistsQuery

- java.lang.Object
- - org.apache.lucene.search.Query
  - - org.apache.lucene.search.NormsFieldExistsQuery

-     public final class NormsFieldExistsQuery
      extends Query

  A `Query` that matches documents that have a value for a given field as reported by field norms. This will not work for fields that omit norms, e.g. `StringField`.

- - ### Constructor Summary

    Constructors
    Constructor and Description
    `NormsFieldExistsQuery(String field)` Create a query that will match that have a value for the given `field`.

  - ### Method Summary

    All Methods Instance Methods Concrete Methods
    Modifier and Type | Method and Description
    --- | ---
    `Weight` | `createWeight(IndexSearcher searcher, ScoreMode scoreMode, float boost)` Expert: Constructs an appropriate Weight implementation for this query.
    `boolean` | `equals(Object other)` Override and implement query instance equivalence properly in a subclass.
    `String` | `getField()`
    `int` | `hashCode()` Override and implement query hash code properly in a subclass.
    `String` | `toString(String field)` Prints a query to a string, with `field` assumed to be the default field and omitted.
    `void` | `visit(QueryVisitor visitor)` Recurse through the query tree, visiting any child queries

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

      `classHash, rewrite, sameClassAs, toString`

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

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

- - ### Constructor Detail

    - #### NormsFieldExistsQuery

          public NormsFieldExistsQuery(String field)

      Create a query that will match that have a value for the given `field`.

  - ### Method Detail

    - #### getField

          public String getField()

    - #### equals

          public boolean equals(Object other)

      Description copied from class: `Query`
      Override and implement query instance equivalence properly in a subclass. This is required so that `QueryCache` works properly. Typically a query will be equal to another only if it's an instance of the same class and its document-filtering properties are identical that other instance. Utility methods are provided for certain repetitive code.
      Specified by:
        `equals` in class `Query`
      See Also:
        `Query.sameClassAs(Object)`, `Query.classHash()`

    - #### hashCode

          public int hashCode()

      Description copied from class: `Query`
      Override and implement query hash code properly in a subclass. This is required so that `QueryCache` works properly.
      Specified by:
        `hashCode` in class `Query`
      See Also:
        `Query.equals(Object)`

    - #### toString

          public String toString(String field)

      Description copied from class: `Query`
      Prints a query to a string, with `field` assumed to be the default field and omitted.
      Specified by:
        `toString` in class `Query`

    - #### visit

          public void visit(QueryVisitor visitor)

      Description copied from class: `Query`
      Recurse through the query tree, visiting any child queries
      Overrides:
        `visit` in class `Query`
      Parameters:
        `visitor` - a QueryVisitor to be called by each query in the tree

    - #### createWeight

          public Weight createWeight(IndexSearcher searcher,
                                     ScoreMode scoreMode,
                                     float boost)
                              throws IOException

      Description copied from class: `Query`
      Expert: Constructs an appropriate Weight implementation for this query.

      Only implemented by primitive queries, which re-write to themselves.

      Overrides:
        `createWeight` in class `Query`
        `scoreMode` - How the produced scorers will be consumed.
        `boost` - The boost that is propagated by the parent queries.
      Throws:
        `IOException`

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