Package org.apache.lucene.search

# Class RegexpQuery

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

All Implemented Interfaces:
  `Accountable`

public class RegexpQuery extends AutomatonQuery
A fast regular expression query based on the `org.apache.lucene.util.automaton` package.

- Comparisons are fast
- The term dictionary is enumerated in an intelligent way, to avoid comparisons. See `AutomatonQuery` for more details.

The supported syntax is documented in the `RegExp` class. Note this might be different than other regular expression implementations. For some alternatives with different syntax, look under the sandbox.

Note this query can be slow, as it needs to iterate over many terms. In order to prevent extremely slow RegexpQueries, a Regexp term should not start with the expression `.*`

See Also:
  - `RegExp`
WARNING: This API is experimental and might change in incompatible ways in the next release.

## 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
Modifier and Type
Field
Description
`static final AutomatonProvider`
`DEFAULT_PROVIDER`
A provider that provides no named automata

### 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
`RegexpQuery(Term term)`
Constructs a query for terms matching `term`.
`RegexpQuery(Term term, int flags)`
Constructs a query for terms matching `term`.
`RegexpQuery(Term term, int flags, int determinizeWorkLimit)`
Constructs a query for terms matching `term`.
`RegexpQuery(Term term, int syntaxFlags, int matchFlags, int determinizeWorkLimit)`
Constructs a query for terms matching `term`.
`RegexpQuery(Term term, int syntaxFlags, int matchFlags, AutomatonProvider provider, int determinizeWorkLimit, MultiTermQuery.RewriteMethod rewriteMethod)`
Constructs a query for terms matching `term`.
`RegexpQuery(Term term, int syntaxFlags, int matchFlags, AutomatonProvider provider, int determinizeWorkLimit, MultiTermQuery.RewriteMethod rewriteMethod, boolean doDeterminization)`
Constructs a query for terms matching `term`.
`RegexpQuery(Term term, int syntaxFlags, AutomatonProvider provider, int determinizeWorkLimit)`
Constructs a query for terms matching `term`.

## Method Summary

Modifier and Type
Method
Description
`Term`
`getRegexp()`
Returns the regexp of this query wrapped in a Term.
`String`
`toString(String field)`
Prints a user-readable version of this query.

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

`equals, getAutomaton, getCompiled, getTermsEnum, hashCode, 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`

## Field Details

### DEFAULT_PROVIDER

public static final AutomatonProvider DEFAULT_PROVIDER
A provider that provides no named automata

## Constructor Details

### RegexpQuery

public RegexpQuery(Term term)
Constructs a query for terms matching `term`.

By default, all regular expression features are enabled.

Parameters:
  `term` - regular expression.

### RegexpQuery

public RegexpQuery(Term term, int flags)
Constructs a query for terms matching `term`.

Parameters:
  `term` - regular expression.
  `flags` - optional RegExp features from `RegExp`

### RegexpQuery

public RegexpQuery(Term term, int flags, int determinizeWorkLimit)
Constructs a query for terms matching `term`.

Parameters:
  `term` - regular expression.
  `flags` - optional RegExp syntax features from `RegExp`
  `determinizeWorkLimit` - maximum effort to spend while compiling the automaton from this regexp. Set higher to allow more complex queries and lower to prevent memory exhaustion. Use `Operations.DEFAULT_DETERMINIZE_WORK_LIMIT` as a decent default if you don't otherwise know what to specify.

### RegexpQuery

public RegexpQuery(Term term, int syntaxFlags, int matchFlags, int determinizeWorkLimit)
Constructs a query for terms matching `term`.

Parameters:
  `term` - regular expression.
  `syntaxFlags` - optional RegExp syntax features from `RegExp` automaton for the regexp can result in. Set higher to allow more complex queries and lower to prevent memory exhaustion.
  `matchFlags` - boolean 'or' of match behavior options such as case insensitivity
  `determinizeWorkLimit` - maximum effort to spend while compiling the automaton from this regexp. Set higher to allow more complex queries and lower to prevent memory exhaustion. Use `Operations.DEFAULT_DETERMINIZE_WORK_LIMIT` as a decent default if you don't otherwise know what to specify.

### RegexpQuery

public RegexpQuery(Term term, int syntaxFlags, AutomatonProvider provider, int determinizeWorkLimit)
Constructs a query for terms matching `term`.

Parameters:
  `term` - regular expression.
  `syntaxFlags` - optional RegExp features from `RegExp`
  `provider` - custom AutomatonProvider for named automata
  `determinizeWorkLimit` - maximum effort to spend while compiling the automaton from this regexp. Set higher to allow more complex queries and lower to prevent memory exhaustion. Use `Operations.DEFAULT_DETERMINIZE_WORK_LIMIT` as a decent default if you don't otherwise know what to specify.

### RegexpQuery

public RegexpQuery(Term term, int syntaxFlags, int matchFlags, AutomatonProvider provider, int determinizeWorkLimit, MultiTermQuery.RewriteMethod rewriteMethod)
Constructs a query for terms matching `term`.

Parameters:
  `term` - regular expression.
  `syntaxFlags` - optional RegExp features from `RegExp`
  `matchFlags` - boolean 'or' of match behavior options such as case insensitivity
  `provider` - custom AutomatonProvider for named automata
  `determinizeWorkLimit` - maximum effort to spend while compiling the automaton from this regexp. Set higher to allow more complex queries and lower to prevent memory exhaustion. Use `Operations.DEFAULT_DETERMINIZE_WORK_LIMIT` as a decent default if you don't otherwise know what to specify.
  `rewriteMethod` - the rewrite method to use to build the final query

### RegexpQuery

public RegexpQuery(Term term, int syntaxFlags, int matchFlags, AutomatonProvider provider, int determinizeWorkLimit, MultiTermQuery.RewriteMethod rewriteMethod, boolean doDeterminization)
Constructs a query for terms matching `term`.

Parameters:
  `term` - regular expression.
  `syntaxFlags` - optional RegExp features from `RegExp`
  `matchFlags` - boolean 'or' of match behavior options such as case insensitivity
  `provider` - custom AutomatonProvider for named automata
  `determinizeWorkLimit` - maximum effort to spend while compiling the automaton from this regexp. Set higher to allow more complex queries and lower to prevent memory exhaustion. Use `Operations.DEFAULT_DETERMINIZE_WORK_LIMIT` as a decent default if you don't otherwise know what to specify.
  `rewriteMethod` - the rewrite method to use to build the final query
  `doDeterminization` - whether do determinization to force the query to use DFA as runAutomaton, if false, the query will not try to determinize the generated automaton from regexp such that it might or might not be a DFA. In case it is an NFA, the query will eventually use `NFARunAutomaton` to execute. Notice that `NFARunAutomaton` is not thread-safe, so better to avoid rewritten method like `MultiTermQuery.CONSTANT_SCORE_BLENDED_REWRITE` when searcher is configured with an executor service

## Method Details

### getRegexp

public Term getRegexp()
Returns the regexp of this query wrapped in a Term.

### toString

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

Overrides:
  `toString` in class `AutomatonQuery`