/*
* Licensed to the Apache Software Foundation (ASF) under one or more
* contributor license agreements. See the NOTICE file distributed with
* this work for additional information regarding copyright ownership.
* The ASF licenses this file to You under the Apache License, Version 2.0
* (the "License"); you may not use this file except in compliance with
* the License. You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package org.apache.lucene.queries.payloads;
import java.io.IOException;
import java.util.List;
import java.util.Map;
import java.util.Objects;
import java.util.Set;
import org.apache.lucene.index.IndexReader;
import org.apache.lucene.index.LeafReaderContext;
import org.apache.lucene.index.PostingsEnum;
import org.apache.lucene.index.Term;
import org.apache.lucene.index.TermContext;
import org.apache.lucene.index.Terms;
import org.apache.lucene.search.IndexSearcher;
import org.apache.lucene.search.Query;
import org.apache.lucene.search.similarities.Similarity;
import org.apache.lucene.search.spans.FilterSpans;
import org.apache.lucene.search.spans.FilterSpans.AcceptStatus;
import org.apache.lucene.search.spans.SpanCollector;
import org.apache.lucene.search.spans.SpanQuery;
import org.apache.lucene.search.spans.SpanScorer;
import org.apache.lucene.search.spans.SpanWeight;
import org.apache.lucene.search.spans.Spans;
import org.apache.lucene.util.BytesRef;
/**
* Only return those matches that have a specific payload at the given position.
*/
public class SpanPayloadCheckQuery extends SpanQuery {
protected final List<BytesRef> payloadToMatch;
protected final SpanQuery match;
/**
* @param match The underlying {@link org.apache.lucene.search.spans.SpanQuery} to check
* @param payloadToMatch The {@link java.util.List} of payloads to match
*/
public SpanPayloadCheckQuery(SpanQuery match, List<BytesRef> payloadToMatch) {
this.match = match;
this.payloadToMatch = payloadToMatch;
}
@Override
public String getField() {
return match.getField();
}
@Override
public SpanWeight createWeight(IndexSearcher searcher, boolean needsScores, float boost) throws IOException {
SpanWeight matchWeight = match.createWeight(searcher, false, boost);
return new SpanPayloadCheckWeight(searcher, needsScores ? getTermContexts(matchWeight) : null, matchWeight, boost);
}
@Override
public Query rewrite(IndexReader reader) throws IOException {
Query matchRewritten = match.rewrite(reader);
if (match != matchRewritten && matchRewritten instanceof SpanQuery) {
return new SpanPayloadCheckQuery((SpanQuery)matchRewritten, payloadToMatch);
}
return super.rewrite(reader);
}
/**
* Weight that pulls its Spans using a PayloadSpanCollector
*/
public class SpanPayloadCheckWeight extends SpanWeight {
final SpanWeight matchWeight;
public SpanPayloadCheckWeight(IndexSearcher searcher, Map<Term, TermContext> termContexts, SpanWeight matchWeight, float boost) throws IOException {
super(SpanPayloadCheckQuery.this, searcher, termContexts, boost);
this.matchWeight = matchWeight;
}
@Override
public void extractTerms(Set<Term> terms) {
matchWeight.extractTerms(terms);
}
@Override
public void extractTermContexts(Map<Term, TermContext> contexts) {
matchWeight.extractTermContexts(contexts);
}
@Override
public Spans getSpans(final LeafReaderContext context, Postings requiredPostings) throws IOException {
final PayloadChecker collector = new PayloadChecker();
Spans matchSpans = matchWeight.getSpans(context, requiredPostings.atLeast(Postings.PAYLOADS));
return (matchSpans == null) ? null : new FilterSpans(matchSpans) {
@Override
protected AcceptStatus accept(Spans candidate) throws IOException {
collector.reset();
candidate.collect(collector);
return collector.match();
}
};
}
@Override
public SpanScorer scorer(LeafReaderContext context) throws IOException {
if (field == null)
return null;
Terms terms = context.reader().terms(field);
if (terms != null && terms.hasPositions() == false) {
throw new IllegalStateException("field \"" + field + "\" was indexed without position data; cannot run SpanQuery (query=" + parentQuery + ")");
}
final Spans spans = getSpans(context, Postings.PAYLOADS);
if (spans == null) {
return null;
}
final Similarity.SimScorer docScorer = getSimScorer(context);
return new SpanScorer(this, spans, docScorer);
}
}
private class PayloadChecker implements SpanCollector {
int upto = 0;
boolean matches = true;
@Override
public void collectLeaf(PostingsEnum postings, int position, Term term) throws IOException {
if (!matches)
return;
if (upto >= payloadToMatch.size()) {
matches = false;
return;
}
BytesRef payload = postings.getPayload();
if (payloadToMatch.get(upto) == null) {
matches = payload == null;
upto++;
return;
}
if (payload == null) {
matches = false;
upto++;
return;
}
matches = payloadToMatch.get(upto).bytesEquals(payload);
upto++;
}
AcceptStatus match() {
return matches && upto == payloadToMatch.size() ? AcceptStatus.YES : AcceptStatus.NO;
}
@Override
public void reset() {
this.upto = 0;
this.matches = true;
}
}
@Override
public String toString(String field) {
StringBuilder buffer = new StringBuilder();
buffer.append("SpanPayloadCheckQuery(");
buffer.append(match.toString(field));
buffer.append(", payloadRef: ");
for (BytesRef bytes : payloadToMatch) {
buffer.append(Term.toString(bytes));
buffer.append(';');
}
buffer.append(")");
return buffer.toString();
}
@Override
public boolean equals(Object other) {
return sameClassAs(other) &&
payloadToMatch.equals(((SpanPayloadCheckQuery) other).payloadToMatch) &&
match.equals(((SpanPayloadCheckQuery) other).match);
}
@Override
public int hashCode() {
int result = classHash();
result = 31 * result + Objects.hashCode(match);
result = 31 * result + Objects.hashCode(payloadToMatch);
return result;
}
}