Package org.apache.lucene.search

# Class PrefixQuery

java.lang.Object
org.apache.lucene.search.Query
org.apache.lucene.search.MultiTermQuery
org.apache.lucene.search.AutomatonQuery
org.apache.lucene.search.PrefixQuery

All Implemented Interfaces:
  `Accountable`

public class PrefixQuery extends AutomatonQuery
A Query that matches documents containing terms with a specified prefix. A PrefixQuery is built by QueryParser for input like `app*`.

This query uses the `MultiTermQuery.CONSTANT_SCORE_BLENDED_REWRITE` rewrite method.

## Nested Class Summary

## Nested classes/interfaces inherited from class org.apache.lucene.search.MultiTermQuery

`MultiTermQuery.RewriteMethod, MultiTermQuery.TopTermsBlendedFreqScoringRewrite, MultiTermQuery.TopTermsBoostOnlyBooleanQueryRewrite, MultiTermQuery.TopTermsScoringBooleanQueryRewrite`

## Field Summary

### Fields inherited from class org.apache.lucene.search.AutomatonQuery

`automaton, automatonIsBinary, compiled, term`

### Fields inherited from class org.apache.lucene.search.MultiTermQuery

`CONSTANT_SCORE_BLENDED_REWRITE, CONSTANT_SCORE_BOOLEAN_REWRITE, CONSTANT_SCORE_REWRITE, DOC_VALUES_REWRITE, field, rewriteMethod, SCORING_BOOLEAN_REWRITE`

### Fields inherited from interface org.apache.lucene.util.Accountable

`NULL_ACCOUNTABLE`

## Constructor Summary

Constructors
Constructor
Description
`PrefixQuery(Term prefix)`
Constructs a query for terms starting with `prefix`.
`PrefixQuery(Term prefix, MultiTermQuery.RewriteMethod rewriteMethod)`
Constructs a query for terms starting with `prefix` using a defined RewriteMethod

## Method Summary

Modifier and Type
Method
Description
`boolean`
`equals(Object obj)`
Override and implement query instance equivalence properly in a subclass.
`Term`
`getPrefix()`
Returns the prefix of this query.
`int`
`hashCode()`
Override and implement query hash code properly in a subclass.
`static Automaton`
`toAutomaton(BytesRef prefix)`
Build an automaton accepting all terms with the specified prefix.
`String`
`toString(String field)`
Prints a user-readable version of this query.

### Methods inherited from class org.apache.lucene.search.AutomatonQuery

`getAutomaton, getCompiled, getTermsEnum, isAutomatonBinary, ramBytesUsed, visit`

### Methods inherited from class org.apache.lucene.search.MultiTermQuery

`getField, getRewriteMethod, getTermsCount, getTermsEnum, rewrite`

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

`classHash, createWeight, sameClassAs, toString`

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

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

### Methods inherited from interface org.apache.lucene.util.Accountable

`getChildResources`

## Constructor Details

### PrefixQuery

public PrefixQuery(Term prefix)
Constructs a query for terms starting with `prefix`.

### PrefixQuery

public PrefixQuery(Term prefix, MultiTermQuery.RewriteMethod rewriteMethod)
Constructs a query for terms starting with `prefix` using a defined RewriteMethod

## Method Details

### toAutomaton

public static Automaton toAutomaton(BytesRef prefix)
Build an automaton accepting all terms with the specified prefix.

### getPrefix

public Term getPrefix()
Returns the prefix of this query.

### toString

public String toString(String field)
Prints a user-readable version of this query.

Overrides:
  `toString` in class `AutomatonQuery`

### 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.

Overrides:
  `hashCode` in class `AutomatonQuery`
See Also:
  - `Query.equals(Object)`

### equals

public boolean equals(Object obj)
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.

Overrides:
  `equals` in class `AutomatonQuery`
See Also:
  - `Query.sameClassAs(Object)`
  - `Query.classHash()`