Package org.apache.lucene.search
Class FieldComparator.TermOrdValComparator
- java.lang.Object
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- org.apache.lucene.search.FieldComparator<BytesRef>
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- org.apache.lucene.search.FieldComparator.TermOrdValComparator
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- All Implemented Interfaces:
LeafFieldComparator
- Enclosing class:
- FieldComparator<T>
public static class FieldComparator.TermOrdValComparator extends FieldComparator<BytesRef> implements LeafFieldComparator
Sorts by field's natural Term sort order, using ordinals. This is functionally equivalent toFieldComparator.TermValComparator
, but it first resolves the string to their relative ordinal positions (using the index returned byLeafReader.getSortedDocValues(String)
), and does most comparisons using the ordinals. For medium to large results, this comparator will be much faster thanFieldComparator.TermValComparator
. For very small result sets it may be slower.
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Nested Class Summary
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Nested classes/interfaces inherited from class org.apache.lucene.search.FieldComparator
FieldComparator.DocComparator, FieldComparator.DoubleComparator, FieldComparator.FloatComparator, FieldComparator.IntComparator, FieldComparator.LongComparator, FieldComparator.NumericComparator<T extends Number>, FieldComparator.RelevanceComparator, FieldComparator.TermOrdValComparator, FieldComparator.TermValComparator
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Constructor Summary
Constructors Constructor Description TermOrdValComparator(int numHits, String field)
Creates this, sorting missing values first.TermOrdValComparator(int numHits, String field, boolean sortMissingLast)
Creates this, with control over how missing values are sorted.
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Method Summary
All Methods Instance Methods Concrete Methods Modifier and Type Method Description int
compare(int slot1, int slot2)
Compare hit at slot1 with hit at slot2.int
compareBottom(int doc)
Compare the bottom of the queue with this doc.int
compareTop(int doc)
Compare the top value with this doc.int
compareValues(BytesRef val1, BytesRef val2)
Returns a negative integer if first is less than second, 0 if they are equal and a positive integer otherwise.void
copy(int slot, int doc)
This method is called when a new hit is competitive.LeafFieldComparator
getLeafComparator(LeafReaderContext context)
Get a per-segmentLeafFieldComparator
to collect the givenLeafReaderContext
.protected SortedDocValues
getSortedDocValues(LeafReaderContext context, String field)
Retrieves the SortedDocValues for the field in this segmentvoid
setBottom(int bottom)
Set the bottom slot, ie the "weakest" (sorted last) entry in the queue.void
setScorer(Scorable scorer)
Sets the Scorer to use in case a document's score is needed.void
setTopValue(BytesRef value)
Record the top value, for future calls toLeafFieldComparator.compareTop(int)
.BytesRef
value(int slot)
Return the actual value in the slot.
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Constructor Detail
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TermOrdValComparator
public TermOrdValComparator(int numHits, String field)
Creates this, sorting missing values first.
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TermOrdValComparator
public TermOrdValComparator(int numHits, String field, boolean sortMissingLast)
Creates this, with control over how missing values are sorted. Pass sortMissingLast=true to put missing values at the end.
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Method Detail
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compare
public int compare(int slot1, int slot2)
Description copied from class:FieldComparator
Compare hit at slot1 with hit at slot2.- Specified by:
compare
in classFieldComparator<BytesRef>
- Parameters:
slot1
- first slot to compareslot2
- second slot to compare- Returns:
- any
N < 0
if slot2's value is sorted after slot1, anyN > 0
if the slot2's value is sorted before slot1 and0
if they are equal
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compareBottom
public int compareBottom(int doc) throws IOException
Description copied from interface:LeafFieldComparator
Compare the bottom of the queue with this doc. This will only invoked after setBottom has been called. This should return the same result asFieldComparator.compare(int,int)
} as if bottom were slot1 and the new document were slot 2.For a search that hits many results, this method will be the hotspot (invoked by far the most frequently).
- Specified by:
compareBottom
in interfaceLeafFieldComparator
- Parameters:
doc
- that was hit- Returns:
- any
N < 0
if the doc's value is sorted after the bottom entry (not competitive), anyN > 0
if the doc's value is sorted before the bottom entry and0
if they are equal. - Throws:
IOException
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copy
public void copy(int slot, int doc) throws IOException
Description copied from interface:LeafFieldComparator
This method is called when a new hit is competitive. You should copy any state associated with this document that will be required for future comparisons, into the specified slot.- Specified by:
copy
in interfaceLeafFieldComparator
- Parameters:
slot
- which slot to copy the hit todoc
- docID relative to current reader- Throws:
IOException
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getSortedDocValues
protected SortedDocValues getSortedDocValues(LeafReaderContext context, String field) throws IOException
Retrieves the SortedDocValues for the field in this segment- Throws:
IOException
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getLeafComparator
public LeafFieldComparator getLeafComparator(LeafReaderContext context) throws IOException
Description copied from class:FieldComparator
Get a per-segmentLeafFieldComparator
to collect the givenLeafReaderContext
. All docIDs supplied to thisLeafFieldComparator
are relative to the current reader (you must add docBase if you need to map it to a top-level docID).- Specified by:
getLeafComparator
in classFieldComparator<BytesRef>
- Parameters:
context
- current reader context- Returns:
- the comparator to use for this segment
- Throws:
IOException
- if there is a low-level IO error
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setBottom
public void setBottom(int bottom) throws IOException
Description copied from interface:LeafFieldComparator
Set the bottom slot, ie the "weakest" (sorted last) entry in the queue. WhenLeafFieldComparator.compareBottom(int)
is called, you should compare against this slot. This will always be called beforeLeafFieldComparator.compareBottom(int)
.- Specified by:
setBottom
in interfaceLeafFieldComparator
- Parameters:
bottom
- the currently weakest (sorted last) slot in the queue- Throws:
IOException
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setTopValue
public void setTopValue(BytesRef value)
Description copied from class:FieldComparator
Record the top value, for future calls toLeafFieldComparator.compareTop(int)
. This is only called for searches that use searchAfter (deep paging), and is called before any calls toFieldComparator.getLeafComparator(LeafReaderContext)
.- Specified by:
setTopValue
in classFieldComparator<BytesRef>
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value
public BytesRef value(int slot)
Description copied from class:FieldComparator
Return the actual value in the slot.- Specified by:
value
in classFieldComparator<BytesRef>
- Parameters:
slot
- the value- Returns:
- value in this slot
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compareTop
public int compareTop(int doc) throws IOException
Description copied from interface:LeafFieldComparator
Compare the top value with this doc. This will only invoked after setTopValue has been called. This should return the same result asFieldComparator.compare(int,int)
} as if topValue were slot1 and the new document were slot 2. This is only called for searches that use searchAfter (deep paging).- Specified by:
compareTop
in interfaceLeafFieldComparator
- Parameters:
doc
- that was hit- Returns:
- any
N < 0
if the doc's value is sorted after the top entry (not competitive), anyN > 0
if the doc's value is sorted before the top entry and0
if they are equal. - Throws:
IOException
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compareValues
public int compareValues(BytesRef val1, BytesRef val2)
Description copied from class:FieldComparator
Returns a negative integer if first is less than second, 0 if they are equal and a positive integer otherwise. Default impl to assume the type implements Comparable and invoke .compareTo; be sure to override this method if your FieldComparator's type isn't a Comparable or if your values may sometimes be null- Overrides:
compareValues
in classFieldComparator<BytesRef>
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setScorer
public void setScorer(Scorable scorer)
Description copied from interface:LeafFieldComparator
Sets the Scorer to use in case a document's score is needed.- Specified by:
setScorer
in interfaceLeafFieldComparator
- Parameters:
scorer
- Scorer instance that you should use to obtain the current hit's score, if necessary.
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