package org.apache.lucene.search.payloads;
/**
* 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.
*/
import org.apache.lucene.index.IndexReader;
import org.apache.lucene.search.Explanation;
import org.apache.lucene.search.Scorer;
import org.apache.lucene.search.Searcher;
import org.apache.lucene.search.Similarity;
import org.apache.lucene.search.Weight;
import org.apache.lucene.search.spans.NearSpansOrdered;
import org.apache.lucene.search.spans.NearSpansUnordered;
import org.apache.lucene.search.spans.SpanNearQuery;
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.ToStringUtils;
import java.io.IOException;
import java.util.Collection;
import java.util.Iterator;
/**
* This class is very similar to
* {@link org.apache.lucene.search.spans.SpanNearQuery} except that it factors
* in the value of the payloads located at each of the positions where the
* {@link org.apache.lucene.search.spans.TermSpans} occurs.
* <p/>
* In order to take advantage of this, you must override
* {@link org.apache.lucene.search.Similarity#scorePayload}
* which returns 1 by default.
* <p/>
* Payload scores are aggregated using a pluggable {@link PayloadFunction}.
*
* @see org.apache.lucene.search.Similarity#scorePayload
*/
public class PayloadNearQuery extends SpanNearQuery {
protected String fieldName;
protected PayloadFunction function;
public PayloadNearQuery(SpanQuery[] clauses, int slop, boolean inOrder) {
this(clauses, slop, inOrder, new AveragePayloadFunction());
}
public PayloadNearQuery(SpanQuery[] clauses, int slop, boolean inOrder,
PayloadFunction function) {
super(clauses, slop, inOrder);
fieldName = clauses[0].getField(); // all clauses must have same field
this.function = function;
}
@Override
public Weight createWeight(Searcher searcher) throws IOException {
return new PayloadNearSpanWeight(this, searcher);
}
@Override
public Object clone() {
int sz = clauses.size();
SpanQuery[] newClauses = new SpanQuery[sz];
for (int i = 0; i < sz; i++) {
newClauses[i] = (SpanQuery) clauses.get(i).clone();
}
PayloadNearQuery boostingNearQuery = new PayloadNearQuery(newClauses, slop,
inOrder);
boostingNearQuery.setBoost(getBoost());
return boostingNearQuery;
}
@Override
public String toString(String field) {
StringBuilder buffer = new StringBuilder();
buffer.append("payloadNear([");
Iterator<SpanQuery> i = clauses.iterator();
while (i.hasNext()) {
SpanQuery clause = i.next();
buffer.append(clause.toString(field));
if (i.hasNext()) {
buffer.append(", ");
}
}
buffer.append("], ");
buffer.append(slop);
buffer.append(", ");
buffer.append(inOrder);
buffer.append(")");
buffer.append(ToStringUtils.boost(getBoost()));
return buffer.toString();
}
@Override
public int hashCode() {
final int prime = 31;
int result = super.hashCode();
result = prime * result + ((fieldName == null) ? 0 : fieldName.hashCode());
result = prime * result + ((function == null) ? 0 : function.hashCode());
return result;
}
@Override
public boolean equals(Object obj) {
if (this == obj)
return true;
if (!super.equals(obj))
return false;
if (getClass() != obj.getClass())
return false;
PayloadNearQuery other = (PayloadNearQuery) obj;
if (fieldName == null) {
if (other.fieldName != null)
return false;
} else if (!fieldName.equals(other.fieldName))
return false;
if (function == null) {
if (other.function != null)
return false;
} else if (!function.equals(other.function))
return false;
return true;
}
public class PayloadNearSpanWeight extends SpanWeight {
public PayloadNearSpanWeight(SpanQuery query, Searcher searcher)
throws IOException {
super(query, searcher);
}
@Override
public Scorer scorer(IndexReader reader, boolean scoreDocsInOrder,
boolean topScorer) throws IOException {
return new PayloadNearSpanScorer(query.getSpans(reader), this,
similarity, reader.norms(query.getField()));
}
}
public class PayloadNearSpanScorer extends SpanScorer {
Spans spans;
protected float payloadScore;
private int payloadsSeen;
Similarity similarity = getSimilarity();
protected PayloadNearSpanScorer(Spans spans, Weight weight,
Similarity similarity, byte[] norms) throws IOException {
super(spans, weight, similarity, norms);
this.spans = spans;
}
// Get the payloads associated with all underlying subspans
public void getPayloads(Spans[] subSpans) throws IOException {
for (int i = 0; i < subSpans.length; i++) {
if (subSpans[i] instanceof NearSpansOrdered) {
if (((NearSpansOrdered) subSpans[i]).isPayloadAvailable()) {
processPayloads(((NearSpansOrdered) subSpans[i]).getPayload(),
subSpans[i].start(), subSpans[i].end());
}
getPayloads(((NearSpansOrdered) subSpans[i]).getSubSpans());
} else if (subSpans[i] instanceof NearSpansUnordered) {
if (((NearSpansUnordered) subSpans[i]).isPayloadAvailable()) {
processPayloads(((NearSpansUnordered) subSpans[i]).getPayload(),
subSpans[i].start(), subSpans[i].end());
}
getPayloads(((NearSpansUnordered) subSpans[i]).getSubSpans());
}
}
}
/**
* By default, uses the {@link PayloadFunction} to score the payloads, but
* can be overridden to do other things.
*
* @param payLoads The payloads
* @param start The start position of the span being scored
* @param end The end position of the span being scored
*
* @see Spans
*/
protected void processPayloads(Collection<byte[]> payLoads, int start, int end) {
for (final byte[] thePayload : payLoads) {
payloadScore = function.currentScore(doc, fieldName, start, end,
payloadsSeen, payloadScore, similarity.scorePayload(doc, fieldName,
spans.start(), spans.end(), thePayload, 0, thePayload.length));
++payloadsSeen;
}
}
//
@Override
protected boolean setFreqCurrentDoc() throws IOException {
if (!more) {
return false;
}
Spans[] spansArr = new Spans[1];
spansArr[0] = spans;
payloadScore = 0;
payloadsSeen = 0;
getPayloads(spansArr);
return super.setFreqCurrentDoc();
}
@Override
public float score() throws IOException {
return super.score()
* function.docScore(doc, fieldName, payloadsSeen, payloadScore);
}
@Override
protected Explanation explain(int doc) throws IOException {
Explanation result = new Explanation();
Explanation nonPayloadExpl = super.explain(doc);
result.addDetail(nonPayloadExpl);
Explanation payloadBoost = new Explanation();
result.addDetail(payloadBoost);
float avgPayloadScore = (payloadsSeen > 0 ? (payloadScore / payloadsSeen)
: 1);
payloadBoost.setValue(avgPayloadScore);
payloadBoost.setDescription("scorePayload(...)");
result.setValue(nonPayloadExpl.getValue() * avgPayloadScore);
result.setDescription("bnq, product of:");
return result;
}
}
}