nl.inl.blacklab.search.lucene

Class BLSpanOrQuery

java.lang.Object

org.apache.lucene.search.Query

org.apache.lucene.search.spans.SpanQuery

nl.inl.blacklab.search.lucene.BLSpanQuery

nl.inl.blacklab.search.lucene.BLSpanOrQuery

All Implemented Interfaces:

Cloneable

public final class BLSpanOrQuery
extends BLSpanQuery

Matches the union of its clauses.

Nested Class Summary

Nested Classes

Modifier and Type	Class and Description
class	BLSpanOrQuery.SpanOrWeight

Field Summary

Fields inherited from class nl.inl.blacklab.search.lucene.BLSpanQuery

MAX_UNLIMITED

Constructor Summary

Constructors

Constructor and Description
BLSpanOrQuery(BLSpanQuery... clauses) Construct a SpanOrQuery merging the provided clauses.

Method Summary

Modifier and Type	Method and Description
boolean	canMakeNfa()
BLSpanWeight	createWeight(org.apache.lucene.search.IndexSearcher searcher, boolean needsScores)
boolean	equals(Object o)
int	forwardMatchingCost() Return an (very rough) indication of how expensive finding a match for this query using an NFA would be.
org.apache.lucene.search.spans.SpanQuery[]	getClauses() Return the clauses whose spans are matched.
protected static int	getCostCalculationSkip(int n) For great numbers of clauses, approximate by only calculating cost of some terms
String	getField()
Nfa	getNfa(ForwardIndexAccessor fiAccessor, int direction)
protected boolean	getNfaTokenStateTerms(Set<String> terms) Checks if this OR node could be converted into a single NFA token state with a list of terms, and collects the terms.
String	getRealField()
int	hashCode()
boolean	hitsAllSameLength() Do our hits have constant length?
boolean	hitsAreUnique() Is it guaranteed that no two hits have the same start and end position?
boolean	hitsEndPointSorted() When hit B follows hit A, is it guaranteed that B.end >= A.end? Also, if A.end == B.end, is B.start > A.start?
boolean	hitsHaveUniqueEnd() Is it guaranteed that no two hits have the same end position?
boolean	hitsHaveUniqueStart() Is it guaranteed that no two hits have the same start position?
int	hitsLengthMax() How long could our longest hit be?
int	hitsLengthMin() How long could our shortest hit be?
boolean	hitsStartPointSorted() When hit B follows hit A, is it guaranteed that B.start >= A.start? Also, if A.start == B.start, is B.end > A.end?
boolean	matchesEmptySequence() Does this query match the empty sequence? For example, the query [word="cow"]* matches the empty sequence.
BLSpanQuery	noEmpty() Return a version of this clause that cannot match the empty sequence.
long	reverseMatchingCost(org.apache.lucene.index.IndexReader reader) Return an (very rough) indication of how many hits this clause might return.
BLSpanQuery	rewrite(org.apache.lucene.index.IndexReader reader)
void	setClausesAreSimpleTermsInSameProperty(boolean b)
void	setField(String luceneField) Explicitly set the field for this query.
void	setHitsAreFixedLength(int i)
String	toString(String field)

Methods inherited from class nl.inl.blacklab.search.lucene.BLSpanQuery

addMaxValues, canInternalizeNeighbour, ensureSorted, ensureSortedUnique, getNfaTwoWay, inf, internalizeNeighbour, inverted, isSingleTokenNot, log, optimize, producesSingleTokens, setQueryInfo, wrap

Methods inherited from class org.apache.lucene.search.spans.SpanQuery

getTermContexts, getTermContexts

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

clone, getBoost, setBoost, toString

Methods inherited from class java.lang.Object

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

Constructor Detail

BLSpanOrQuery

public BLSpanOrQuery(BLSpanQuery... clauses)

Construct a SpanOrQuery merging the provided clauses. All clauses must have the same field.

Parameters:

clauses - clauses to OR together

Method Detail

getClauses

public org.apache.lucene.search.spans.SpanQuery[] getClauses()

Return the clauses whose spans are matched.

Returns:

the clauses

setField

public void setField(String luceneField)

Explicitly set the field for this query. Required because some queries rewrite to 0-clause or queries, and we need to be able to call get[Real]Field() later.

Parameters:

luceneField - the Lucene field for this query (what getRealField() returns)

getField

public String getField()

Overrides:

getField in class BLSpanQuery

getRealField

public String getRealField()

Specified by:

getRealField in class BLSpanQuery

rewrite

public BLSpanQuery rewrite(org.apache.lucene.index.IndexReader reader)
                    throws IOException

Specified by:

rewrite in class BLSpanQuery

Throws:

IOException

matchesEmptySequence

public boolean matchesEmptySequence()

Description copied from class: BLSpanQuery

Does this query match the empty sequence? For example, the query [word="cow"]* matches the empty sequence. We need to know this so we can rewrite to the appropriate queries. A query of the form "AB*" would be translated into "A|AB+", so each component of the query actually generates non-empty matches. We default to no because most queries don't match the empty sequence.

Overrides:

matchesEmptySequence in class BLSpanQuery

Returns:

true if this query matches the empty sequence, false otherwise

noEmpty

public BLSpanQuery noEmpty()

Description copied from class: BLSpanQuery

Return a version of this clause that cannot match the empty sequence.

Returns:

a version that doesn't match the empty sequence

hitsAllSameLength

public boolean hitsAllSameLength()

Description copied from class: BLSpanQuery

Do our hits have constant length?

Specified by:

hitsAllSameLength in class BLSpanQuery

Returns:

true if they do, false if not

hitsLengthMin

public int hitsLengthMin()

Description copied from class: BLSpanQuery

How long could our shortest hit be?

Specified by:

hitsLengthMin in class BLSpanQuery

Returns:

length of the shortest hit possible

hitsLengthMax

public int hitsLengthMax()

Description copied from class: BLSpanQuery

How long could our longest hit be?

Specified by:

hitsLengthMax in class BLSpanQuery

Returns:

length of the longest hit possible, or Integer.MAX_VALUE if unlimited

hitsEndPointSorted

public boolean hitsEndPointSorted()

Description copied from class: BLSpanQuery

When hit B follows hit A, is it guaranteed that B.end >= A.end? Also, if A.end == B.end, is B.start > A.start?

Specified by:

hitsEndPointSorted in class BLSpanQuery

Returns:

true if this is guaranteed, false if not

hitsStartPointSorted

public boolean hitsStartPointSorted()

Description copied from class: BLSpanQuery

When hit B follows hit A, is it guaranteed that B.start >= A.start? Also, if A.start == B.start, is B.end > A.end?

Specified by:

hitsStartPointSorted in class BLSpanQuery

Returns:

true if this is guaranteed, false if not

hitsHaveUniqueStart

public boolean hitsHaveUniqueStart()

Description copied from class: BLSpanQuery

Is it guaranteed that no two hits have the same start position?

Specified by:

hitsHaveUniqueStart in class BLSpanQuery

Returns:

true if this is guaranteed, false if not

hitsHaveUniqueEnd

public boolean hitsHaveUniqueEnd()

Description copied from class: BLSpanQuery

Is it guaranteed that no two hits have the same end position?

Specified by:

hitsHaveUniqueEnd in class BLSpanQuery

Returns:

true if this is guaranteed, false if not

hitsAreUnique

public boolean hitsAreUnique()

Description copied from class: BLSpanQuery

Is it guaranteed that no two hits have the same start and end position?

Specified by:

hitsAreUnique in class BLSpanQuery

Returns:

true if this is guaranteed, false if not

toString

public String toString(String field)

Specified by:

toString in class BLSpanQuery

equals

public boolean equals(Object o)

Specified by:

equals in class BLSpanQuery

hashCode

public int hashCode()

Specified by:

hashCode in class BLSpanQuery

createWeight

public BLSpanWeight createWeight(org.apache.lucene.search.IndexSearcher searcher,
                                 boolean needsScores)
                          throws IOException

Specified by:

createWeight in class BLSpanQuery

Throws:

IOException

getNfa

public Nfa getNfa(ForwardIndexAccessor fiAccessor,
                  int direction)

Overrides:

getNfa in class BLSpanQuery

getNfaTokenStateTerms

protected boolean getNfaTokenStateTerms(Set<String> terms)

Checks if this OR node could be converted into a single NFA token state with a list of terms, and collects the terms.

Parameters:

terms - terms for the NFA token state, if possible (or null if we're not interested in the terms)

Returns:

true if this node can be converted into a single NFA token state

canMakeNfa

public boolean canMakeNfa()

Overrides:

canMakeNfa in class BLSpanQuery

reverseMatchingCost

public long reverseMatchingCost(org.apache.lucene.index.IndexReader reader)

Description copied from class: BLSpanQuery

Return an (very rough) indication of how many hits this clause might return. Used to decide what parts of the query to match using the forward index. Based on term frequency, which are combined using simple rules of thumb. Another way to think of this is an indication of how much computation this clause will require when matching using the reverse index.

Specified by:

reverseMatchingCost in class BLSpanQuery

Parameters:

reader - the index reader

Returns:

rough estimation of the number of hits

getCostCalculationSkip

protected static int getCostCalculationSkip(int n)

For great numbers of clauses, approximate by only calculating cost of some terms

Parameters:

n - number of clauses

Returns:

number of clauses to skip after every calculation

forwardMatchingCost

public int forwardMatchingCost()

Description copied from class: BLSpanQuery

Return an (very rough) indication of how expensive finding a match for this query using an NFA would be. Used to decide what parts of the query to match using the forward index.

Specified by:

forwardMatchingCost in class BLSpanQuery

Returns:

rough estimation of the NFA complexity

setHitsAreFixedLength

public void setHitsAreFixedLength(int i)

setClausesAreSimpleTermsInSameProperty

public void setClausesAreSimpleTermsInSameProperty(boolean b)