TermQuery打分过程
作者：互联网
org.apache.lucene.search.IndexSearcher
protected void search(List<LeafReaderContext> leaves, Weight weight, Collector collector)
throws IOException {
// TODO: should we make this
// threaded...? the Collector could be sync'd?
// always use single thread:
for (LeafReaderContext ctx : leaves) { // search each subreader
final LeafCollector leafCollector;
try {
leafCollector = collector.getLeafCollector(ctx);
} catch (CollectionTerminatedException e) {
// there is no doc of interest in this reader context
// continue with the following leaf
continue;
}
BulkScorer scorer = weight.bulkScorer(ctx);
if (scorer != null) {
try {
scorer.score(leafCollector, ctx.reader().getLiveDocs());
} catch (CollectionTerminatedException e) {
// collection was terminated prematurely
// continue with the following leaf
}
}
}
}org.apache.lucene.search.Weight bulkScorer
public BulkScorer bulkScorer(LeafReaderContext context) throws IOException {
Scorer scorer = scorer(context);
if (scorer == null) {
// No docs match
return null;
}
// This impl always scores docs in order, so we can
// ignore scoreDocsInOrder:
return new DefaultBulkScorer(scorer);
}org.apache.lucene.search.TermQuery TermWeight scorer
@Override
public Scorer scorer(LeafReaderContext context) throws IOException {
assert termStates == null || termStates.wasBuiltFor(ReaderUtil.getTopLevelContext(context)) : "The top-reader used to create Weight is not the same as the current reader's top-reader (" + ReaderUtil.getTopLevelContext(context);;
final TermsEnum termsEnum = getTermsEnum(context);
if (termsEnum == null) {
return null;
}
LeafSimScorer scorer = new LeafSimScorer(simScorer, context.reader(), term.field(), scoreMode.needsScores());
if (scoreMode == ScoreMode.TOP_SCORES) {
return new TermScorer(this, termsEnum.impacts(PostingsEnum.FREQS), scorer);
} else {
return new TermScorer(this, termsEnum.postings(null, scoreMode.needsScores() ? PostingsEnum.FREQS : PostingsEnum.NONE), scorer);
}
}protected static class DefaultBulkScorer extends BulkScorer {
private final Scorer scorer;
private final DocIdSetIterator iterator;
private final TwoPhaseIterator twoPhase;
/** Sole constructor. */
public DefaultBulkScorer(Scorer scorer) {
if (scorer == null) {
throw new NullPointerException();
}
this.scorer = scorer;
this.iterator = scorer.iterator();
this.twoPhase = scorer.twoPhaseIterator();
}
@Override
public long cost() {
return iterator.cost();
}
@Override
public int score(LeafCollector collector, Bits acceptDocs, int min, int max) throws IOException {
collector.setScorer(scorer);
if (scorer.docID() == -1 && min == 0 && max == DocIdSetIterator.NO_MORE_DOCS) {
scoreAll(collector, iterator, twoPhase, acceptDocs);
return DocIdSetIterator.NO_MORE_DOCS;
} else {
int doc = scorer.docID();
if (doc < min) {
if (twoPhase == null) {
doc = iterator.advance(min);
} else {
doc = twoPhase.approximation().advance(min);
}
}
return scoreRange(collector, iterator, twoPhase, acceptDocs, doc, max);
}
}
/** Specialized method to bulk-score a range of hits; we
* separate this from {@link #scoreAll} to help out
* hotspot.
* See <a href="https://issues.apache.org/jira/browse/LUCENE-5487">LUCENE-5487</a> */
static int scoreRange(LeafCollector collector, DocIdSetIterator iterator, TwoPhaseIterator twoPhase,
Bits acceptDocs, int currentDoc, int end) throws IOException {
if (twoPhase == null) {
while (currentDoc < end) {
if (acceptDocs == null || acceptDocs.get(currentDoc)) {
collector.collect(currentDoc);
}
currentDoc = iterator.nextDoc();
}
return currentDoc;
} else {
final DocIdSetIterator approximation = twoPhase.approximation();
while (currentDoc < end) {
if ((acceptDocs == null || acceptDocs.get(currentDoc)) && twoPhase.matches()) {
collector.collect(currentDoc);
}
currentDoc = approximation.nextDoc();
}
return currentDoc;
}
}
/** Specialized method to bulk-score all hits; we
* separate this from {@link #scoreRange} to help out
* hotspot.
* See <a href="https://issues.apache.org/jira/browse/LUCENE-5487">LUCENE-5487</a> */
static void scoreAll(LeafCollector collector, DocIdSetIterator iterator, TwoPhaseIterator twoPhase, Bits acceptDocs) throws IOException {
if (twoPhase == null) {
for (int doc = iterator.nextDoc(); doc != DocIdSetIterator.NO_MORE_DOCS; doc = iterator.nextDoc()) {
if (acceptDocs == null || acceptDocs.get(doc)) {
collector.collect(doc);
}
}
} else {
// The scorer has an approximation, so run the approximation first, then check acceptDocs, then confirm
final DocIdSetIterator approximation = twoPhase.approximation();
for (int doc = approximation.nextDoc(); doc != DocIdSetIterator.NO_MORE_DOCS; doc = approximation.nextDoc()) {
if ((acceptDocs == null || acceptDocs.get(doc)) && twoPhase.matches()) {
collector.collect(doc);
}
}
}
}
}注意区分simScore 和 Score
simScore是Score的一个属性
Score是为一个倒排链打分的一个工具类
public final class LeafSimScorer {
private final SimScorer scorer;
private final NumericDocValues norms;
/**
* Sole constructor: Score documents of {@code reader} with {@code scorer}.
*/
public LeafSimScorer(SimScorer scorer, LeafReader reader, String field, boolean needsScores) throws IOException {
this.scorer = Objects.requireNonNull(scorer);
norms = needsScores ? reader.getNormValues(field) : null;
}
/** Return the wrapped {@link SimScorer}. */
public SimScorer getSimScorer() {
return scorer;
}
private long getNormValue(int doc) throws IOException {
if (norms != null) {
boolean found = norms.advanceExact(doc);
assert found;
return norms.longValue();
} else {
return 1L; // default norm
}
}
/** Score the provided document assuming the given term document frequency.
* This method must be called on non-decreasing sequences of doc ids.
* @see SimScorer#score(float, long) */
public float score(int doc, float freq) throws IOException {
return scorer.score(freq, getNormValue(doc));
}
/** Explain the score for the provided document assuming the given term document frequency.
* This method must be called on non-decreasing sequences of doc ids.
* @see SimScorer#explain(Explanation, long) */
public Explanation explain(int doc, Explanation freqExpl) throws IOException {
return scorer.explain(freqExpl, getNormValue(doc));
}
}
/** Expert: A <code>Scorer</code> for documents matching a <code>Term</code>.
*/
final class TermScorer extends Scorer {
private final PostingsEnum postingsEnum;
private final ImpactsEnum impactsEnum;
private final DocIdSetIterator iterator;
private final LeafSimScorer docScorer;
private final ImpactsDISI impactsDisi;
/**
* Construct a {@link TermScorer} that will iterate all documents.
*/
TermScorer(Weight weight, PostingsEnum postingsEnum, LeafSimScorer docScorer) {
super(weight);
iterator = this.postingsEnum = postingsEnum;
impactsEnum = new SlowImpactsEnum(postingsEnum);
impactsDisi = new ImpactsDISI(impactsEnum, impactsEnum, docScorer.getSimScorer());
this.docScorer = docScorer;
}
/**
* Construct a {@link TermScorer} that will use impacts to skip blocks of
* non-competitive documents.
*/
TermScorer(Weight weight, ImpactsEnum impactsEnum, LeafSimScorer docScorer) {
super(weight);
postingsEnum = this.impactsEnum = impactsEnum;
impactsDisi = new ImpactsDISI(impactsEnum, impactsEnum, docScorer.getSimScorer());
iterator = impactsDisi;
this.docScorer = docScorer;
}
@Override
public int docID() {
return postingsEnum.docID();
}
final int freq() throws IOException {
return postingsEnum.freq();
}
@Override
public DocIdSetIterator iterator() {
return iterator;
}
@Override
public float score() throws IOException {
assert docID() != DocIdSetIterator.NO_MORE_DOCS;
return docScorer.score(postingsEnum.docID(), postingsEnum.freq());
}
@Override
public int advanceShallow(int target) throws IOException {
return impactsDisi.advanceShallow(target);
}
@Override
public float getMaxScore(int upTo) throws IOException {
return impactsDisi.getMaxScore(upTo);
}
@Override
public void setMinCompetitiveScore(float minScore) {
impactsDisi.setMinCompetitiveScore(minScore);
}
/** Returns a string representation of this <code>TermScorer</code>. */
@Override
public String toString() { return "scorer(" + weight + ")[" + super.toString() + "]"; }
}标签：return,final,iterator,doc,public,TermQuery,scorer,过程,打分 来源： https://blog.csdn.net/chuanyangwang/article/details/121354874