nl.inl.blacklab.search.lucene

Class SpanFuzzyQuery

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.SpanFuzzyQuery

All Implemented Interfaces:

Cloneable

public class SpanFuzzyQuery
extends BLSpanQuery

A fuzzy (approximate) query with spans.

Author:

Karl Wettin <kalle@snigel.net>

Field Summary

Fields

Modifier and Type	Field and Description
static int	defaultMaxEdits
static int	defaultPrefixLength

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

MAX_UNLIMITED

Constructor Summary

Constructors

Constructor and Description
SpanFuzzyQuery(org.apache.lucene.index.Term term)
SpanFuzzyQuery(org.apache.lucene.index.Term term, int maxEdits, int prefixLength)

Method Summary

Modifier and Type	Method and Description
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.
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?
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)
String	toString(String field) Prints a query to a string, with field as the default field for terms.

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

addMaxValues, canInternalizeNeighbour, canMakeNfa, ensureSorted, ensureSortedUnique, getField, getNfa, getNfaTwoWay, inf, internalizeNeighbour, inverted, isSingleTokenNot, log, matchesEmptySequence, 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

Field Detail

defaultMaxEdits

public static final int defaultMaxEdits

See Also:

Constant Field Values

defaultPrefixLength

public static final int defaultPrefixLength

See Also:

Constant Field Values

Constructor Detail

SpanFuzzyQuery

public SpanFuzzyQuery(org.apache.lucene.index.Term term)

SpanFuzzyQuery

public SpanFuzzyQuery(org.apache.lucene.index.Term term,
                      int maxEdits,
                      int prefixLength)

Method Detail

rewrite

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

Specified by:

rewrite in class BLSpanQuery

Throws:

IOException

createWeight

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

Specified by:

createWeight in class BLSpanQuery

Throws:

IOException

getRealField

public String getRealField()

Specified by:

getRealField in class BLSpanQuery

toString

public String toString(String field)

Prints a query to a string, with field as the default field for terms.

The representation used is one that is supposed to be readable by org.apache.lucene.queryParser.QueryParser.QueryParser. However, there are the following limitations:

• If the query was created by the parser, the printed representation may not be exactly what was parsed. For example, characters that need to be escaped will be represented without the required backslash.
• Some of the more complicated queries (e.g. span queries) don't have a representation that can be parsed by QueryParser.

Specified by:

toString in class BLSpanQuery

Parameters:

field -

Returns:

the string representation

equals

public boolean equals(Object o)

Specified by:

equals in class BLSpanQuery

hashCode

public int hashCode()

Specified by:

hashCode in class BLSpanQuery

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

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

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