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

All Implemented Interfaces:

Serializable, Cloneable

Direct Known Subclasses:

FuzzyQuery, NumericRangeQuery, PrefixQuery, TermRangeQuery, WildcardQuery
```
public abstract class MultiTermQuery
extends Query
```
An abstract Query that matches documents containing a subset of terms provided by a FilteredTermEnum enumeration.
This query cannot be used directly; you must subclass it and define getEnum(org.apache.lucene.index.IndexReader) to provide a FilteredTermEnum that iterates through the terms to be matched.
NOTE: if setRewriteMethod(org.apache.lucene.search.MultiTermQuery.RewriteMethod) is either CONSTANT_SCORE_BOOLEAN_QUERY_REWRITE or SCORING_BOOLEAN_QUERY_REWRITE, you may encounter a BooleanQuery.TooManyClauses exception during searching, which happens when the number of terms to be searched exceeds BooleanQuery.getMaxClauseCount(). Setting setRewriteMethod(org.apache.lucene.search.MultiTermQuery.RewriteMethod) to CONSTANT_SCORE_FILTER_REWRITE prevents this.
The recommended rewrite method is CONSTANT_SCORE_AUTO_REWRITE_DEFAULT: it doesn't spend CPU computing unhelpful scores, and it tries to pick the most performant rewrite method given the query. If you need scoring (like FuzzyQuery, use MultiTermQuery.TopTermsScoringBooleanQueryRewrite which uses a priority queue to only collect competitive terms and not hit this limitation. Note that QueryParser produces MultiTermQueries using CONSTANT_SCORE_AUTO_REWRITE_DEFAULT by default.

See Also:

Serialized Form

Nested Class Summary

Nested Classes
Modifier and Type	Class	Description
`static class`	`MultiTermQuery.ConstantScoreAutoRewrite`	A rewrite method that tries to pick the best constant-score rewrite method based on term and document counts from the query.
`static class`	`MultiTermQuery.RewriteMethod`	Abstract class that defines how the query is rewritten.
`static class`	`MultiTermQuery.TopTermsBoostOnlyBooleanQueryRewrite`	A rewrite method that first translates each term into `BooleanClause.Occur.SHOULD` clause in a BooleanQuery, but the scores are only computed as the boost.
`static class`	`MultiTermQuery.TopTermsScoringBooleanQueryRewrite`	A rewrite method that first translates each term into `BooleanClause.Occur.SHOULD` clause in a BooleanQuery, and keeps the scores as computed by the query.

Field Summary

Fields
Modifier and Type	Field	Description
`static MultiTermQuery.RewriteMethod`	`CONSTANT_SCORE_AUTO_REWRITE_DEFAULT`	Read-only default instance of `MultiTermQuery.ConstantScoreAutoRewrite`, with `ConstantScoreAutoRewrite.setTermCountCutoff(int)` set to `ConstantScoreAutoRewrite.DEFAULT_TERM_COUNT_CUTOFF` and `ConstantScoreAutoRewrite.setDocCountPercent(double)` set to `ConstantScoreAutoRewrite.DEFAULT_DOC_COUNT_PERCENT`.
`static MultiTermQuery.RewriteMethod`	`CONSTANT_SCORE_BOOLEAN_QUERY_REWRITE`	Like `SCORING_BOOLEAN_QUERY_REWRITE` except scores are not computed.
`static MultiTermQuery.RewriteMethod`	`CONSTANT_SCORE_FILTER_REWRITE`	A rewrite method that first creates a private Filter, by visiting each term in sequence and marking all docs for that term.
`protected MultiTermQuery.RewriteMethod`	`rewriteMethod`
`static MultiTermQuery.RewriteMethod`	`SCORING_BOOLEAN_QUERY_REWRITE`	A rewrite method that first translates each term into `BooleanClause.Occur.SHOULD` clause in a BooleanQuery, and keeps the scores as computed by the query.

Constructor Summary

Constructors
Constructor Description

MultiTermQuery()
Constructs a query matching terms that cannot be represented with a single Term.

Method Summary

All Methods Instance Methods Abstract Methods Concrete Methods Deprecated Methods
Modifier and Type	Method	Description
`void`	`clearTotalNumberOfTerms()`	Deprecated. Don't use this method, as its not thread safe and useless.
`boolean`	`equals(Object obj)`
`protected abstract FilteredTermEnum`	`getEnum(IndexReader reader)`	Construct the enumeration to be used, expanding the pattern term.
`MultiTermQuery.RewriteMethod`	`getRewriteMethod()`
`int`	`getTotalNumberOfTerms()`	Deprecated. Don't use this method, as its not thread safe and useless.
`int`	`hashCode()`
`protected void`	`incTotalNumberOfTerms(int inc)`	Deprecated. Don't use this method, as its not thread safe and useless.
`Query`	`rewrite(IndexReader reader)`	To rewrite to a simpler form, instead return a simpler enum from `getEnum(IndexReader)`.
`void`	`setRewriteMethod(MultiTermQuery.RewriteMethod method)`	Sets the rewrite method to be used when executing the query.

Methods inherited from class org.apache.lucene.search.Query
clone, combine, createWeight, extractTerms, getBoost, getSimilarity, mergeBooleanQueries, setBoost, toString, toString, weight

Methods inherited from class java.lang.Object
finalize, getClass, notify, notifyAll, wait, wait, wait

- Field Detail
  - rewriteMethod
```
protected MultiTermQuery.RewriteMethod rewriteMethod
```
  - CONSTANT_SCORE_FILTER_REWRITE
```
public static final MultiTermQuery.RewriteMethod CONSTANT_SCORE_FILTER_REWRITE
```
    A rewrite method that first creates a private Filter, by visiting each term in sequence and marking all docs for that term. Matching documents are assigned a constant score equal to the query's boost.
    This method is faster than the BooleanQuery rewrite methods when the number of matched terms or matched documents is non-trivial. Also, it will never hit an errant BooleanQuery.TooManyClauses exception.
    
    See Also:
    
    setRewriteMethod(org.apache.lucene.search.MultiTermQuery.RewriteMethod)
  - SCORING_BOOLEAN_QUERY_REWRITE
```
public static final MultiTermQuery.RewriteMethod SCORING_BOOLEAN_QUERY_REWRITE
```
    A rewrite method that first translates each term into BooleanClause.Occur.SHOULD clause in a BooleanQuery, and keeps the scores as computed by the query. Note that typically such scores are meaningless to the user, and require non-trivial CPU to compute, so it's almost always better to use CONSTANT_SCORE_AUTO_REWRITE_DEFAULT instead.
    NOTE: This rewrite method will hit BooleanQuery.TooManyClauses if the number of terms exceeds BooleanQuery.getMaxClauseCount().
    
    See Also:
    
    setRewriteMethod(org.apache.lucene.search.MultiTermQuery.RewriteMethod)
  - CONSTANT_SCORE_BOOLEAN_QUERY_REWRITE
```
public static final MultiTermQuery.RewriteMethod CONSTANT_SCORE_BOOLEAN_QUERY_REWRITE
```
    Like SCORING_BOOLEAN_QUERY_REWRITE except scores are not computed. Instead, each matching document receives a constant score equal to the query's boost.
    NOTE: This rewrite method will hit BooleanQuery.TooManyClauses if the number of terms exceeds BooleanQuery.getMaxClauseCount().
    
    See Also:
    
    setRewriteMethod(org.apache.lucene.search.MultiTermQuery.RewriteMethod)
  - CONSTANT_SCORE_AUTO_REWRITE_DEFAULT
```
public static final MultiTermQuery.RewriteMethod CONSTANT_SCORE_AUTO_REWRITE_DEFAULT
```
    Read-only default instance of MultiTermQuery.ConstantScoreAutoRewrite, with ConstantScoreAutoRewrite.setTermCountCutoff(int) set to ConstantScoreAutoRewrite.DEFAULT_TERM_COUNT_CUTOFF and ConstantScoreAutoRewrite.setDocCountPercent(double) set to ConstantScoreAutoRewrite.DEFAULT_DOC_COUNT_PERCENT. Note that you cannot alter the configuration of this instance; you'll need to create a private instance instead.
- Constructor Detail
  - MultiTermQuery
```
public MultiTermQuery()
```
    Constructs a query matching terms that cannot be represented with a single Term.
- Method Detail
  - getEnum
```
protected abstract FilteredTermEnum getEnum(IndexReader reader)
                                     throws IOException
```
    Construct the enumeration to be used, expanding the pattern term.
    
    Throws:
    
    IOException
  - getTotalNumberOfTerms
```
@Deprecated
public int getTotalNumberOfTerms()
```
    Deprecated.
    Don't use this method, as its not thread safe and useless.
    
    Expert: Return the number of unique terms visited during execution of the query. If there are many of them, you may consider using another query type or reduce your total term count in index.
    This method is not thread safe, be sure to only call it when no query is running! If you re-use the same query instance for another search, be sure to first reset the term counter with clearTotalNumberOfTerms().
    On single-segment indexes / no MultiReaders, you get the correct number of unique terms for the whole index. Use this number to compare different queries. For multi-segment indexes this number can also be achieved in non-constant-score mode. In constant-score mode you get the total number of terms seeked for all segments / sub-readers.
    
    See Also:
    
    clearTotalNumberOfTerms()
  - clearTotalNumberOfTerms
```
@Deprecated
public void clearTotalNumberOfTerms()
```
    Deprecated.
    Don't use this method, as its not thread safe and useless.
    
    Expert: Resets the counting of unique terms. Do this before executing the query/filter.
    
    See Also:
    
    getTotalNumberOfTerms()
  - incTotalNumberOfTerms
```
@Deprecated
protected void incTotalNumberOfTerms(int inc)
```
    Deprecated.
    Don't use this method, as its not thread safe and useless.
  - rewrite
```
public final Query rewrite(IndexReader reader)
                    throws IOException
```
    To rewrite to a simpler form, instead return a simpler enum from getEnum(IndexReader). For example, to rewrite to a single term, return a SingleTermEnum
    
    Overrides:
    
    rewrite in class Query
    
    Throws:
    
    IOException
  - getRewriteMethod
```
public MultiTermQuery.RewriteMethod getRewriteMethod()
```
    See Also:
    
    setRewriteMethod(org.apache.lucene.search.MultiTermQuery.RewriteMethod)
  - setRewriteMethod
```
public void setRewriteMethod(MultiTermQuery.RewriteMethod method)
```
    Sets the rewrite method to be used when executing the query. You can use one of the four core methods, or implement your own subclass of MultiTermQuery.RewriteMethod.
  - hashCode
```
public int hashCode()
```
    Overrides:
    
    hashCode in class Query
  - equals
```
public boolean equals(Object obj)
```
    Overrides:
    
    equals in class Query

Class MultiTermQuery

Nested Class Summary

Field Summary

Constructor Summary

Method Summary

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

Methods inherited from class java.lang.Object

Field Detail

rewriteMethod

CONSTANT_SCORE_FILTER_REWRITE

SCORING_BOOLEAN_QUERY_REWRITE

CONSTANT_SCORE_BOOLEAN_QUERY_REWRITE

CONSTANT_SCORE_AUTO_REWRITE_DEFAULT

Constructor Detail

MultiTermQuery

Method Detail

getEnum

getTotalNumberOfTerms

clearTotalNumberOfTerms

incTotalNumberOfTerms

rewrite

getRewriteMethod

setRewriteMethod

hashCode

equals