org.apache.lucene.search
Class BooleanQuery

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

All Implemented Interfaces:

java.lang.Cloneable, java.io.Serializable

public class BooleanQuery

extends Query

A Query that matches documents matching boolean combinations of other queries, e.g. TermQuerys, PhraseQuerys or other BooleanQuerys.

See Also:

Serialized Form

Nested Class Summary

static class

BooleanQuery.TooManyClauses Thrown when an attempt is made to add more than getMaxClauseCount() clauses.

Field Summary

static int	maxClauseCount Deprecated. use setMaxClauseCount(int) instead
protected int	minNrShouldMatch

Constructor Summary

BooleanQuery()
Constructs an empty boolean query.

BooleanQuery(boolean disableCoord)
Constructs an empty boolean query.

Method Summary

void	add(BooleanClause clause) Adds a clause to a boolean query.
void	add(Query query, boolean required, boolean prohibited) Deprecated. use add(Query, BooleanClause.Occur) instead: For add(query, true, false) use add(query, BooleanClause.Occur.MUST) For add(query, false, false) use add(query, BooleanClause.Occur.SHOULD) For add(query, false, true) use add(query, BooleanClause.Occur.MUST_NOT)
void	add(Query query, BooleanClause.Occur occur) Adds a clause to a boolean query.
java.lang.Object	clone() Returns a clone of this query.
protected Weight	createWeight(Searcher searcher) Expert: Constructs an appropriate Weight implementation for this query.
boolean	equals(java.lang.Object o) Returns true iff o is equal to this.
void	extractTerms(java.util.Set terms) Expert: adds all terms occuring in this query to the terms set.
BooleanClause[]	getClauses() Returns the set of clauses in this query.
static int	getMaxClauseCount() Return the maximum number of clauses permitted, 1024 by default.
int	getMinimumNumberShouldMatch() Gets the minimum number of the optional BooleanClauses which must be satisifed.
Similarity	getSimilarity(Searcher searcher) Expert: Returns the Similarity implementation to be used for this query.
static boolean	getUseScorer14()
int	hashCode() Returns a hash code value for this object.
boolean	isCoordDisabled() Returns true iff Similarity.coord(int,int) is disabled in scoring for this query instance.
Query	rewrite(IndexReader reader) Expert: called to re-write queries into primitive queries.
static void	setMaxClauseCount(int maxClauseCount) Set the maximum number of clauses permitted per BooleanQuery.
void	setMinimumNumberShouldMatch(int min) Specifies a minimum number of the optional BooleanClauses which must be satisifed.
static void	setUseScorer14(boolean use14)
java.lang.String	toString(java.lang.String field) Prints a user-readable version of this query.

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

combine, getBoost, mergeBooleanQueries, setBoost, toString, weight

Methods inherited from class java.lang.Object

finalize, getClass, notify, notifyAll, wait, wait, wait

Field Detail

maxClauseCount

public static int maxClauseCount

Deprecated. use setMaxClauseCount(int) instead

minNrShouldMatch

protected int minNrShouldMatch

Constructor Detail

BooleanQuery

public BooleanQuery()

Constructs an empty boolean query.

BooleanQuery

public BooleanQuery(boolean disableCoord)

Constructs an empty boolean query. Similarity.coord(int,int) may be disabled in scoring, as appropriate. For example, this score factor does not make sense for most automatically generated queries, like WildcardQuery and FuzzyQuery.

Parameters:

disableCoord - disables Similarity.coord(int,int) in scoring.

Method Detail

getMaxClauseCount

public static int getMaxClauseCount()

Return the maximum number of clauses permitted, 1024 by default. Attempts to add more than the permitted number of clauses cause BooleanQuery.TooManyClauses to be thrown.

See Also:

setMaxClauseCount(int)

setMaxClauseCount

public static void setMaxClauseCount(int maxClauseCount)

Set the maximum number of clauses permitted per BooleanQuery. Default value is 1024.

TermQuery clauses are generated from for example prefix queries and fuzzy queries. Each TermQuery needs some buffer space during search, so this parameter indirectly controls the maximum buffer requirements for query search.

When this parameter becomes a bottleneck for a Query one can use a Filter. For example instead of a RangeQuery one can use a RangeFilter.

Normally the buffers are allocated by the JVM. When using for example MMapDirectory the buffering is left to the operating system.

isCoordDisabled

public boolean isCoordDisabled()

Returns true iff Similarity.coord(int,int) is disabled in scoring for this query instance.

See Also:

BooleanQuery(boolean)

getSimilarity

public Similarity getSimilarity(Searcher searcher)

Description copied from class: Query

Expert: Returns the Similarity implementation to be used for this query. Subclasses may override this method to specify their own Similarity implementation, perhaps one that delegates through that of the Searcher. By default the Searcher's Similarity implementation is returned.

Overrides:

getSimilarity in class Query

setMinimumNumberShouldMatch

public void setMinimumNumberShouldMatch(int min)

Specifies a minimum number of the optional BooleanClauses which must be satisifed.

By default no optional clauses are neccessary for a match (unless there are no required clauses). If this method is used, then the specified numebr of clauses is required.

Use of this method is totally independant of specifying that any specific clauses are required (or prohibited). This number will only be compared against the number of matching optional clauses.

EXPERT NOTE: Using this method will force the use of BooleanWeight2, regardless of wether setUseScorer14(true) has been called.

Parameters:

min - the number of optional clauses that must match

See Also:

setUseScorer14(boolean)

getMinimumNumberShouldMatch

public int getMinimumNumberShouldMatch()

Gets the minimum number of the optional BooleanClauses which must be satisifed.

add

public void add(Query query,
                boolean required,
                boolean prohibited)

Deprecated. use add(Query, BooleanClause.Occur) instead:

• For add(query, true, false) use add(query, BooleanClause.Occur.MUST)
• For add(query, false, false) use add(query, BooleanClause.Occur.SHOULD)
• For add(query, false, true) use add(query, BooleanClause.Occur.MUST_NOT)

Adds a clause to a boolean query. Clauses may be:

• required which means that documents which do not match this sub-query will not match the boolean query;
• prohibited which means that documents which do match this sub-query will not match the boolean query; or
• neither, in which case matched documents are neither prohibited from nor required to match the sub-query. However, a document must match at least 1 sub-query to match the boolean query.

It is an error to specify a clause as both required and prohibited.

add

public void add(Query query,
                BooleanClause.Occur occur)

Adds a clause to a boolean query.

Throws:

BooleanQuery.TooManyClauses - if the new number of clauses exceeds the maximum clause number

See Also:

getMaxClauseCount()

add

public void add(BooleanClause clause)

Adds a clause to a boolean query.

Throws:

BooleanQuery.TooManyClauses - if the new number of clauses exceeds the maximum clause number

See Also:

getMaxClauseCount()

getClauses

public BooleanClause[] getClauses()

Returns the set of clauses in this query.

setUseScorer14

public static void setUseScorer14(boolean use14)

getUseScorer14

public static boolean getUseScorer14()

createWeight

protected Weight createWeight(Searcher searcher)
                       throws java.io.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

Throws:

java.io.IOException

rewrite

public Query rewrite(IndexReader reader)
              throws java.io.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.

Overrides:

rewrite in class Query

Throws:

java.io.IOException

extractTerms

public void extractTerms(java.util.Set terms)

Description copied from class: Query

Expert: adds all terms occuring in this query to the terms set. Only works if this query is in its rewritten form.

Overrides:

extractTerms in class Query

clone

public java.lang.Object clone()

Description copied from class: Query

Returns a clone of this query.

Overrides:

clone in class Query

toString

public java.lang.String toString(java.lang.String field)

Prints a user-readable version of this query.

Specified by:

toString in class Query

equals

public boolean equals(java.lang.Object o)

Returns true iff o is equal to this.

hashCode

public int hashCode()

Returns a hash code value for this object.