package org.apache.lucene.search;
import java.util.concurrent.atomic.LongAccumulator;
final class MaxScoreAccumulator {
static final int DEFAULT_INTERVAL = 0x3ff;
final LongAccumulator acc = new LongAccumulator(Long::max, Long.MIN_VALUE);
long modInterval;
MaxScoreAccumulator() {
this.modInterval = DEFAULT_INTERVAL;
}
void accumulate(int docID, float score) {
assert docID >= 0 && score >= 0;
long encode = (((long) Float.floatToIntBits(score)) << 32) | docID;
acc.accumulate(encode);
}
DocAndScore get() {
long value = acc.get();
if (value == Long.MIN_VALUE) {
return null;
}
float score = Float.intBitsToFloat((int) (value >> 32));
int docID = (int) value;
return new DocAndScore(docID, score);
}
static class DocAndScore implements Comparable<DocAndScore> {
final int docID;
final float score;
DocAndScore(int docID, float score) {
this.docID = docID;
this.score = score;
}
@Override
public int compareTo(DocAndScore o) {
int cmp = Float.compare(score, o.score);
if (cmp == 0) {
return Integer.compare(docID, o.docID);
}
return cmp;
}
@Override
public boolean equals(Object o) {
if (this == o) return true;
if (o == null || getClass() != o.getClass()) return false;
DocAndScore result = (DocAndScore) o;
return docID == result.docID &&
Float.compare(result.score, score) == 0;
}
@Override
public String toString() {
return "DocAndScore{" +
"docID=" + docID +
", score=" + score +
'}';
}
}
}