Package org.apache.lucene.search

# Class ConstantScoreQuery

java.lang.Object
org.apache.lucene.search.Query
org.apache.lucene.search.ConstantScoreQuery

public final class ConstantScoreQuery extends Query
A query that wraps another query and simply returns a constant score equal to 1 for every document that matches the query. It therefore simply strips of all scores and always returns 1.

## Nested Class Summary

Nested Classes
Modifier and Type
Class
Description
`protected static class`
`ConstantScoreQuery.ConstantBulkScorer`
We return this as our `BulkScorer` so that if the CSQ wraps a query with its own optimized top-level scorer (e.g.

## Constructor Summary

Constructors
Constructor
Description
`ConstantScoreQuery(Query query)`
Strips off scores from the passed in Query.

## Method Summary

Modifier and Type
Method
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.
`Query`
`getQuery()`
Returns the encapsulated query.
`int`
`hashCode()`
Override and implement query hash code properly in a subclass.
`Query`
`rewrite(IndexSearcher indexSearcher)`
Expert: called to re-write queries into primitive queries.
`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, sameClassAs, toString`

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

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

## Constructor Details

### ConstantScoreQuery

public ConstantScoreQuery(Query query)
Strips off scores from the passed in Query. The hits will get a constant score of 1.

## Method Details

### getQuery

public Query getQuery()
Returns the encapsulated query.

### rewrite

public Query rewrite(IndexSearcher indexSearcher) throws IOException
Description copied from class: `Query`
Expert: called to re-write queries into primitive queries. For example, a PrefixQuery will be rewritten into a BooleanQuery that consists of TermQuerys.

Callers are expected to call `rewrite` multiple times if necessary, until the rewritten query is the same as the original query.

The rewrite process may be able to make use of IndexSearcher's executor and be executed in parallel if the executor is provided.

Overrides:
  `rewrite` in class `Query`
Throws:
  `IOException`
See Also:
  - `IndexSearcher.rewrite(Query)`

### visit

public void visit(QueryVisitor visitor)
Description copied from class: `Query`
Recurse through the query tree, visiting any child queries.

Specified by:
  `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`
Parameters:
  `scoreMode` - How the produced scorers will be consumed.
  `boost` - The boost that is propagated by the parent queries.
Throws:
  `IOException`

### 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`

### 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 to those of the 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)`