package org.apache.lucene.search;
/*
* 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 java.io.IOException;
import java.util.Set;
import org.apache.lucene.index.AtomicReaderContext;
import org.apache.lucene.index.DocsEnum;
import org.apache.lucene.index.AtomicReader;
import org.apache.lucene.index.IndexReaderContext;
import org.apache.lucene.index.ReaderUtil;
import org.apache.lucene.index.Term;
import org.apache.lucene.index.TermContext;
import org.apache.lucene.index.TermState;
import org.apache.lucene.index.TermsEnum;
import org.apache.lucene.search.similarities.Similarity.SimScorer;
import org.apache.lucene.search.similarities.Similarity;
import org.apache.lucene.util.Bits;
import org.apache.lucene.util.ToStringUtils;
/** A Query that matches documents containing a term.
This may be combined with other terms with a {@link BooleanQuery}.
*/
public class TermQuery extends Query {
private final Term term;
private final int docFreq;
private final TermContext perReaderTermState;
final class TermWeight extends Weight {
private final Similarity similarity;
private final Similarity.SimWeight stats;
private final TermContext termStates;
public TermWeight(IndexSearcher searcher, TermContext termStates)
throws IOException {
assert termStates != null : "TermContext must not be null";
this.termStates = termStates;
this.similarity = searcher.getSimilarity();
this.stats = similarity.computeWeight(
getBoost(),
searcher.collectionStatistics(term.field()),
searcher.termStatistics(term, termStates));
}
@Override
public String toString() { return "weight(" + TermQuery.this + ")"; }
@Override
public Query getQuery() { return TermQuery.this; }
@Override
public float getValueForNormalization() {
return stats.getValueForNormalization();
}
@Override
public void normalize(float queryNorm, float topLevelBoost) {
stats.normalize(queryNorm, topLevelBoost);
}
@Override
public Scorer scorer(AtomicReaderContext context, 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 = getTermsEnum(context);
if (termsEnum == null) {
return null;
}
DocsEnum docs = termsEnum.docs(acceptDocs, null);
assert docs != null;
return new TermScorer(this, docs, similarity.simScorer(stats, context));
}
/**
* Returns a {@link TermsEnum} positioned at this weights Term or null if
* the term does not exist in the given context
*/
private TermsEnum getTermsEnum(AtomicReaderContext context) throws IOException {
final TermState state = termStates.get(context.ord);
if (state == null) { // term is not present in that reader
assert termNotInReader(context.reader(), term) : "no termstate found but term exists in reader term=" + term;
return null;
}
//System.out.println("LD=" + reader.getLiveDocs() + " set?=" + (reader.getLiveDocs() != null ? reader.getLiveDocs().get(0) : "null"));
final TermsEnum termsEnum = context.reader().terms(term.field()).iterator(null);
termsEnum.seekExact(term.bytes(), state);
return termsEnum;
}
private boolean termNotInReader(AtomicReader reader, Term term) throws IOException {
// only called from assert
//System.out.println("TQ.termNotInReader reader=" + reader + " term=" + field + ":" + bytes.utf8ToString());
return reader.docFreq(term) == 0;
}
@Override
public Explanation explain(AtomicReaderContext context, int doc) throws IOException {
Scorer scorer = scorer(context, context.reader().getLiveDocs());
if (scorer != null) {
int newDoc = scorer.advance(doc);
if (newDoc == doc) {
float freq = scorer.freq();
SimScorer docScorer = similarity.simScorer(stats, context);
ComplexExplanation result = new ComplexExplanation();
result.setDescription("weight("+getQuery()+" in "+doc+") [" + similarity.getClass().getSimpleName() + "], result of:");
Explanation scoreExplanation = docScorer.explain(doc, new Explanation(freq, "termFreq=" + freq));
result.addDetail(scoreExplanation);
result.setValue(scoreExplanation.getValue());
result.setMatch(true);
return result;
}
}
return new ComplexExplanation(false, 0.0f, "no matching term");
}
}
/** Constructs a query for the term <code>t</code>. */
public TermQuery(Term t) {
this(t, -1);
}
/** Expert: constructs a TermQuery that will use the
* provided docFreq instead of looking up the docFreq
* against the searcher. */
public TermQuery(Term t, int docFreq) {
term = t;
this.docFreq = docFreq;
perReaderTermState = null;
}
/** Expert: constructs a TermQuery that will use the
* provided docFreq instead of looking up the docFreq
* against the searcher. */
public TermQuery(Term t, TermContext states) {
assert states != null;
term = t;
docFreq = states.docFreq();
perReaderTermState = states;
}
/** Returns the term of this query. */
public Term getTerm() { return term; }
@Override
public Weight createWeight(IndexSearcher searcher) throws IOException {
final IndexReaderContext context = searcher.getTopReaderContext();
final TermContext termState;
if (perReaderTermState == null || perReaderTermState.topReaderContext != context) {
// make TermQuery single-pass if we don't have a PRTS or if the context differs!
termState = TermContext.build(context, term);
} else {
// PRTS was pre-build for this IS
termState = this.perReaderTermState;
}
// we must not ignore the given docFreq - if set use the given value (lie)
if (docFreq != -1)
termState.setDocFreq(docFreq);
return new TermWeight(searcher, termState);
}
@Override
public void extractTerms(Set<Term> terms) {
terms.add(getTerm());
}
/** Prints a user-readable version of this query. */
@Override
public String toString(String field) {
StringBuilder buffer = new StringBuilder();
if (!term.field().equals(field)) {
buffer.append(term.field());
buffer.append(":");
}
buffer.append(term.text());
buffer.append(ToStringUtils.boost(getBoost()));
return buffer.toString();
}
/** Returns true iff <code>o</code> is equal to this. */
@Override
public boolean equals(Object o) {
if (!(o instanceof TermQuery))
return false;
TermQuery other = (TermQuery)o;
return (this.getBoost() == other.getBoost())
&& this.term.equals(other.term);
}
/** Returns a hash code value for this object.*/
@Override
public int hashCode() {
return Float.floatToIntBits(getBoost()) ^ term.hashCode();
}
}