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IntArrayDocIdSet.java
import java.io.IOException;
import java.util.Arrays;
import org.apache.lucene.search.DocIdSet;
import org.apache.lucene.search.DocIdSetIterator;
import org.apache.lucene.util.ArrayUtil;
import org.apache.lucene.util.RamUsageEstimator;
public class IntArrayDocIdSet extends DocIdSet {
private static final long BASE_RAM_BYTES_USED = RamUsageEstimator.shallowSizeOfInstance(IntArrayDocIdSet.class);
public static class Builder {
private int[] docIDs = new int[0];
int off;
public void add(int docID) {
if (off > 0 && docID <= docIDs[off - 1]) {
throw new IllegalArgumentException();
}
if (off == docIDs.length) {
docIDs = ArrayUtil.grow(docIDs);
}
docIDs[off++] = docID;
}
public IntArrayDocIdSet build() {
add(DocIdSetIterator.NO_MORE_DOCS);
final IntArrayDocIdSet set = new IntArrayDocIdSet(Arrays.copyOf(docIDs, off));
docIDs = null;
return set;
}
}
private final int[] docIDs;
public IntArrayDocIdSet(int[] docIDs) {
this.docIDs = docIDs;
}
@Override
public long ramBytesUsed() {
return BASE_RAM_BYTES_USED + RamUsageEstimator.sizeOf(docIDs);
}
@Override
public DocIdSetIterator iterator() throws IOException {
return new Iterator(docIDs);
}
private static class Iterator extends DocIdSetIterator {
private final int[] docIDs;
int i;
public Iterator(int[] docIDs) {
this.docIDs = docIDs;
i = -1;
}
@Override
public int docID() {
if (i == -1) {
return -1;
}
return docIDs[i];
}
@Override
public int nextDoc() throws IOException {
return docIDs[++i];
}
@Override
public int advance(int target) throws IOException {
int lo = i + 1;
int hi = lo + 1;
while (hi < docIDs.length && docIDs[hi] < target) {
final int diff = hi - lo;
lo = hi;
hi += 2 * diff;
}
hi = Math.min(hi, docIDs.length);
i = Arrays.binarySearch(docIDs, lo, hi, target);
if (i < 0) {
i = -1 - i;
}
return docIDs[i];
}
@Override
public long cost() {
return docIDs.length - 1;
}
}
}
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