Package org.apache.lucene.search
Class FieldComparator.RelevanceComparator
java.lang.Object
org.apache.lucene.search.FieldComparator<Float>
org.apache.lucene.search.FieldComparator.RelevanceComparator
- All Implemented Interfaces:
LeafFieldComparator
- Enclosing class:
FieldComparator<T>
public static final class FieldComparator.RelevanceComparator
extends FieldComparator<Float>
implements LeafFieldComparator
Sorts by descending relevance. NOTE: if you are sorting only by descending relevance and then
secondarily by ascending docID, performance is faster using
TopScoreDocCollector
directly (which IndexSearcher.search(Query, int) uses when no Sort is
specified).-
Nested Class Summary
Nested classes/interfaces inherited from class org.apache.lucene.search.FieldComparator
FieldComparator.RelevanceComparator, FieldComparator.TermValComparator -
Constructor Summary
ConstructorsConstructorDescriptionRelevanceComparator(int numHits) Creates a new comparator based on relevance fornumHits. -
Method Summary
Modifier and TypeMethodDescriptionintcompare(int slot1, int slot2) Compare hit at slot1 with hit at slot2.intcompareBottom(int doc) Compare the bottom of the queue with this doc.intcompareTop(int doc) Compare the top value with this doc.intcompareValues(Float first, Float second) Returns a negative integer if first is less than second, 0 if they are equal and a positive integer otherwise.voidcopy(int slot, int doc) This method is called when a new hit is competitive.getLeafComparator(LeafReaderContext context) Get a per-segmentLeafFieldComparatorto collect the givenLeafReaderContext.voidsetBottom(int bottom) Set the bottom slot, ie the "weakest" (sorted last) entry in the queue.voidSets the Scorer to use in case a document's score is needed.voidsetTopValue(Float value) Record the top value, for future calls toLeafFieldComparator.compareTop(int).value(int slot) Return the actual value in the slot.Methods inherited from class org.apache.lucene.search.FieldComparator
disableSkipping, setSingleSortMethods inherited from class java.lang.Object
clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, waitMethods inherited from interface org.apache.lucene.search.LeafFieldComparator
competitiveIterator, setHitsThresholdReached
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Constructor Details
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RelevanceComparator
public RelevanceComparator(int numHits) Creates a new comparator based on relevance fornumHits.
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Method Details
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compare
public int compare(int slot1, int slot2) Description copied from class:FieldComparatorCompare hit at slot1 with hit at slot2.- Specified by:
comparein classFieldComparator<Float>- Parameters:
slot1- first slot to compareslot2- second slot to compare- Returns:
- any
N < 0if slot2's value is sorted after slot1, anyN > 0if the slot2's value is sorted before slot1 and0if they are equal
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compareBottom
Description copied from interface:LeafFieldComparatorCompare 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:
compareBottomin interfaceLeafFieldComparator- Parameters:
doc- that was hit- Returns:
- any
N < 0if the doc's value is sorted after the bottom entry (not competitive), anyN > 0if the doc's value is sorted before the bottom entry and0if they are equal. - Throws:
IOException
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copy
Description copied from interface:LeafFieldComparatorThis 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:
copyin interfaceLeafFieldComparator- Parameters:
slot- which slot to copy the hit todoc- docID relative to current reader- Throws:
IOException
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getLeafComparator
Description copied from class:FieldComparatorGet a per-segmentLeafFieldComparatorto collect the givenLeafReaderContext. All docIDs supplied to thisLeafFieldComparatorare relative to the current reader (you must add docBase if you need to map it to a top-level docID).- Specified by:
getLeafComparatorin classFieldComparator<Float>- Parameters:
context- current reader context- Returns:
- the comparator to use for this segment
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setBottom
public void setBottom(int bottom) Description copied from interface:LeafFieldComparatorSet 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:
setBottomin interfaceLeafFieldComparator- Parameters:
bottom- the currently weakest (sorted last) slot in the queue
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setTopValue
Description copied from class:FieldComparatorRecord 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:
setTopValuein classFieldComparator<Float>
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setScorer
Description copied from interface:LeafFieldComparatorSets the Scorer to use in case a document's score is needed.- Specified by:
setScorerin interfaceLeafFieldComparator- Parameters:
scorer- Scorer instance that you should use to obtain the current hit's score, if necessary.
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value
Description copied from class:FieldComparatorReturn the actual value in the slot.- Specified by:
valuein classFieldComparator<Float>- Parameters:
slot- the value- Returns:
- value in this slot
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compareValues
Description copied from class:FieldComparatorReturns 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:
compareValuesin classFieldComparator<Float>
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compareTop
Description copied from interface:LeafFieldComparatorCompare 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:
compareTopin interfaceLeafFieldComparator- Parameters:
doc- that was hit- Returns:
- any
N < 0if the doc's value is sorted after the top entry (not competitive), anyN > 0if the doc's value is sorted before the top entry and0if they are equal. - Throws:
IOException
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