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.DocsEnum;
import org.apache.lucene.index.IndexReader;
import org.apache.lucene.index.TermState;
import org.apache.lucene.index.Terms;
import org.apache.lucene.index.IndexReader.AtomicReaderContext;
import org.apache.lucene.index.IndexReader.ReaderContext;
import org.apache.lucene.index.Term;
import org.apache.lucene.search.Explanation.IDFExplanation;
import org.apache.lucene.util.BytesRef;
import org.apache.lucene.util.PerReaderTermState;
import org.apache.lucene.util.ReaderUtil;
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 int docFreq;
private transient PerReaderTermState perReaderTermState;
private class TermWeight extends Weight {
private final Similarity similarity;
private float value;
private final float idf;
private float queryNorm;
private float queryWeight;
private final IDFExplanation idfExp;
private transient PerReaderTermState termStates;
public TermWeight(IndexSearcher searcher, PerReaderTermState termStates, int docFreq)
throws IOException {
assert termStates != null : "PerReaderTermState must not be null";
this.termStates = termStates;
this.similarity = searcher.getSimilarityProvider().get(term.field());
if (docFreq != -1) {
idfExp = similarity.idfExplain(term, searcher, docFreq);
} else {
idfExp = similarity.idfExplain(term, searcher);
}
idf = idfExp.getIdf();
}
@Override
public String toString() { return "weight(" + TermQuery.this + ")"; }
@Override
public Query getQuery() { return TermQuery.this; }
@Override
public float getValue() { return value; }
@Override
public float sumOfSquaredWeights() {
queryWeight = idf * getBoost(); // compute query weight
return queryWeight * queryWeight; // square it
}
@Override
public void normalize(float queryNorm) {
this.queryNorm = queryNorm;
queryWeight *= queryNorm; // normalize query weight
value = queryWeight * idf; // idf for document
}
@Override
public Scorer scorer(AtomicReaderContext context, ScorerContext scorerContext) throws IOException {
final String field = term.field();
final IndexReader reader = context.reader;
assert termStates.topReaderContext == ReaderUtil.getTopLevelContext(context) : "The top-reader used to create Weight is not the same as the current reader's top-reader";
final TermState state = termStates
.get(context.ord);
if (state == null) { // term is not present in that reader
assert termNotInReader(reader, field, term.bytes()) : "no termstate found but term exists in reader";
return null;
}
final DocsEnum docs = reader.termDocsEnum(reader.getDeletedDocs(), field, term.bytes(), state);
assert docs != null;
return new TermScorer(this, docs, similarity, context.reader.norms(field));
}
private boolean termNotInReader(IndexReader reader, String field, BytesRef bytes) throws IOException {
// only called from assert
final Terms terms = reader.terms(field);
return terms == null || terms.docFreq(bytes) == 0;
}
@Override
public Explanation explain(AtomicReaderContext context, int doc)
throws IOException {
final IndexReader reader = context.reader;
ComplexExplanation result = new ComplexExplanation();
result.setDescription("weight("+getQuery()+" in "+doc+"), product of:");
Explanation expl = new Explanation(idf, idfExp.explain());
// explain query weight
Explanation queryExpl = new Explanation();
queryExpl.setDescription("queryWeight(" + getQuery() + "), product of:");
Explanation boostExpl = new Explanation(getBoost(), "boost");
if (getBoost() != 1.0f)
queryExpl.addDetail(boostExpl);
queryExpl.addDetail(expl);
Explanation queryNormExpl = new Explanation(queryNorm,"queryNorm");
queryExpl.addDetail(queryNormExpl);
queryExpl.setValue(boostExpl.getValue() *
expl.getValue() *
queryNormExpl.getValue());
result.addDetail(queryExpl);
// explain field weight
String field = term.field();
ComplexExplanation fieldExpl = new ComplexExplanation();
fieldExpl.setDescription("fieldWeight("+term+" in "+doc+
"), product of:");
Explanation tfExplanation = new Explanation();
int tf = 0;
DocsEnum docs = reader.termDocsEnum(reader.getDeletedDocs(), term.field(), term.bytes());
if (docs != null) {
int newDoc = docs.advance(doc);
if (newDoc == doc) {
tf = docs.freq();
}
tfExplanation.setValue(similarity.tf(tf));
tfExplanation.setDescription("tf(termFreq("+term+")="+tf+")");
} else {
tfExplanation.setValue(0.0f);
tfExplanation.setDescription("no matching term");
}
fieldExpl.addDetail(tfExplanation);
fieldExpl.addDetail(expl);
Explanation fieldNormExpl = new Explanation();
final byte[] fieldNorms = reader.norms(field);
float fieldNorm =
fieldNorms!=null ? similarity.decodeNormValue(fieldNorms[doc]) : 1.0f;
fieldNormExpl.setValue(fieldNorm);
fieldNormExpl.setDescription("fieldNorm(field="+field+", doc="+doc+")");
fieldExpl.addDetail(fieldNormExpl);
fieldExpl.setMatch(Boolean.valueOf(tfExplanation.isMatch()));
fieldExpl.setValue(tfExplanation.getValue() *
expl.getValue() *
fieldNormExpl.getValue());
result.addDetail(fieldExpl);
result.setMatch(fieldExpl.getMatch());
// combine them
result.setValue(queryExpl.getValue() * fieldExpl.getValue());
if (queryExpl.getValue() == 1.0f)
return fieldExpl;
return result;
}
}
/** 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, PerReaderTermState 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 ReaderContext context = searcher.getTopReaderContext();
final int weightDocFreq;
final PerReaderTermState termState;
if (perReaderTermState == null || perReaderTermState.topReaderContext != context) {
// make TermQuery single-pass if we don't have a PRTS or if the context differs!
termState = PerReaderTermState.build(context, term, true); // cache term lookups!
// we must not ignore the given docFreq - if set use the given value
weightDocFreq = docFreq == -1 ? termState.docFreq() : docFreq;
} else {
// PRTS was pre-build for this IS
termState = this.perReaderTermState;
weightDocFreq = docFreq;
}
return new TermWeight(searcher, termState, weightDocFreq);
}
@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();
}
}