com.sindicetech.siren.search.spans.TermSpanQuery Maven / Gradle / Ivy
/**
* Copyright (c) 2014, Sindice Limited. All Rights Reserved.
*
* This file is part of the SIREn project.
*
* SIREn is a free software: you can redistribute it and/or modify
* it under the terms of the GNU Affero General Public License as
* published by the Free Software Foundation, either version 3 of
* the License, or (at your option) any later version.
*
* SIREn is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU Affero General Public License for more details.
*
* You should have received a copy of the GNU Affero General Public
* License along with this program. If not, see
* A term-based span query matches spans of terms. The positions of the span is relative to the position of a
* {@link org.apache.lucene.index.Term}.
*
* Code taken from {@link org.apache.lucene.search.spans.SpanTermQuery} and adapted for the Siren use case.
*/
public class TermSpanQuery extends DatatypedSpanQuery {
protected Term term;
/**
* TODO: Duplicate code with {@link com.sindicetech.siren.search.node.NodeTermQuery.NodeTermWeight}
*/
protected class TermSpanWeight extends Weight {
private final Similarity similarity;
private final Similarity.SimWeight stats;
private final TermContext termStates;
public TermSpanWeight(final IndexSearcher searcher, final TermContext termStates) throws IOException {
assert termStates != null : "TermContext must not be null";
this.termStates = termStates;
this.similarity = searcher.getSimilarity();
this.stats = similarity.computeWeight(
TermSpanQuery.this.getBoost(),
searcher.collectionStatistics(term.field()),
searcher.termStatistics(term, termStates));
}
@Override
public String toString() {
return "weight(" + TermSpanQuery.this + ")";
}
@Override
public Explanation explain(final AtomicReaderContext context, final int doc) throws IOException {
final NodeScorer scorer = (NodeScorer) this.scorer(context, context.reader().getLiveDocs());
if (scorer != null) {
if (scorer.skipToCandidate(doc) && scorer.doc() == doc) {
final Similarity.SimScorer docScorer = similarity.simScorer(stats, context);
final ComplexExplanation result = new ComplexExplanation();
result.setDescription("weight("+this.getQuery()+" in "+doc+") [" + similarity.getClass().getSimpleName() + "], sum of:");
float sum = 0;
while (scorer.nextNode()) {
final ComplexExplanation nodeMatch = new ComplexExplanation();
nodeMatch.setDescription("in "+scorer.node()+"), result of:");
final float freq = scorer.freqInNode();
final Explanation scoreExplanation = docScorer.explain(doc, new Explanation(freq, "termFreq=" + freq));
nodeMatch.setValue(scoreExplanation.getValue());
sum += scoreExplanation.getValue();
nodeMatch.setMatch(true);
nodeMatch.addDetail(scoreExplanation);
result.addDetail(nodeMatch);
}
result.setValue(sum);
result.setMatch(true);
return result;
}
}
return new ComplexExplanation(false, 0.0f, "no matching term");
}
@Override
public Query getQuery() {
return TermSpanQuery.this;
}
@Override
public float getValueForNormalization() throws IOException {
return stats.getValueForNormalization();
}
@Override
public void normalize(final float norm, final float topLevelBoost) {
stats.normalize(norm, topLevelBoost);
}
@Override
public Scorer scorer(final AtomicReaderContext context, final Bits acceptDocs)
throws IOException {
assert termStates.topReaderContext == ReaderUtil.getTopLevelContext(context) : "The top-reader used to create " +
"Weight (" + termStates.topReaderContext + ") is not the same as the current reader's top-reader (" +
ReaderUtil.getTopLevelContext(context);
final TermsEnum termsEnum = this.getTermsEnum(context);
if (termsEnum == null) {
return null;
}
final DocsAndPositionsEnum docsEnum = termsEnum.docsAndPositions(acceptDocs, null);
final DocsNodesAndPositionsEnum sirenDocsEnum = TermSpanQuery.this.getDocsNodesAndPositionsEnum(docsEnum);
TermSpans spans = new TermSpans(sirenDocsEnum, term, similarity.simScorer(stats, context));
return new SpanScorer(this, spans);
}
/**
* Returns a {@link TermsEnum} positioned at this weights Term or null if
* the term does not exist in the given context
*/
TermsEnum getTermsEnum(final AtomicReaderContext context) throws IOException {
final TermState state = termStates.get(context.ord);
if (state == null) { // term is not present in that reader
assert this.termNotInReader(context.reader(), term) : "no termstate found but term exists in reader term=" + term;
return null;
}
final TermsEnum termsEnum = context.reader().terms(term.field()).iterator(null);
termsEnum.seekExact(term.bytes(), state);
return termsEnum;
}
private boolean termNotInReader(final AtomicReader reader, final Term term) throws IOException {
// only called from assert
return reader.docFreq(term) == 0;
}
}
/** Construct a TermSpanQuery matching the named term's spans. */
public TermSpanQuery(Term term) { this.term = term; }
/** Return the term whose spans are matched. */
public Term getTerm() { return term; }
@Override
public Weight createWeight(final IndexSearcher searcher) throws IOException {
final IndexReaderContext context = searcher.getTopReaderContext();
final TermContext termState = TermContext.build(context, term);
return new TermSpanWeight(searcher, termState);
}
@Override
public void extractTerms(final Set terms) {
terms.add(term);
}
@Override
public String toString(final String field) {
final StringBuilder builder = new StringBuilder();
final CharSequence text = term.text();
if (text.length() != 0) {
builder.append("'").append(text).append("'");
}
builder.append(ToStringUtils.boost(this.getBoost()));
return this.wrapToStringWithDatatype(builder).toString();
}
@Override
public int hashCode() {
return Float.floatToIntBits(this.getBoost())
^ term.hashCode()
^ levelConstraint
^ upperBound
^ lowerBound;
}
@Override
public boolean equals(final Object o) {
if (!(o instanceof TermSpanQuery)) return false;
final TermSpanQuery other = (TermSpanQuery) o;
return (this.getBoost() == other.getBoost()) &&
this.term.equals(other.term) &&
this.levelConstraint == other.levelConstraint &&
this.lowerBound == other.lowerBound &&
this.upperBound == other.upperBound &&
StringUtils.equals(this.datatype, other.datatype);
}
}