/*
* 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.function.valuesource;
import org.apache.lucene.index.*;
import org.apache.lucene.queries.function.FunctionValues;
import org.apache.lucene.queries.function.docvalues.IntDocValues;
import org.apache.lucene.search.DocIdSetIterator;
import org.apache.lucene.util.BytesRef;
import java.io.IOException;
import java.util.Map;
/**
* Function that returns {@link DocsEnum#freq()} for the
* supplied term in every document.
* <p>
* If the term does not exist in the document, returns 0.
* If frequencies are omitted, returns 1.
*/
public class TermFreqValueSource extends DocFreqValueSource {
public TermFreqValueSource(String field, String val, String indexedField, BytesRef indexedBytes) {
super(field, val, indexedField, indexedBytes);
}
@Override
public String name() {
return "termfreq";
}
@Override
public FunctionValues getValues(Map context, AtomicReaderContext readerContext) throws IOException {
Fields fields = readerContext.reader().fields();
final Terms terms = fields.terms(indexedField);
return new IntDocValues(this) {
DocsEnum docs ;
int atDoc;
int lastDocRequested = -1;
{ reset(); }
public void reset() throws IOException {
// no one should call us for deleted docs?
if (terms != null) {
final TermsEnum termsEnum = terms.iterator(null);
if (termsEnum.seekExact(indexedBytes, false)) {
docs = termsEnum.docs(null, null);
} else {
docs = null;
}
} else {
docs = null;
}
if (docs == null) {
docs = new DocsEnum() {
@Override
public int freq() {
return 0;
}
@Override
public int docID() {
return DocIdSetIterator.NO_MORE_DOCS;
}
@Override
public int nextDoc() {
return DocIdSetIterator.NO_MORE_DOCS;
}
@Override
public int advance(int target) {
return DocIdSetIterator.NO_MORE_DOCS;
}
@Override
public long cost() {
return 0;
}
};
}
atDoc = -1;
}
@Override
public int intVal(int doc) {
try {
if (doc < lastDocRequested) {
// out-of-order access.... reset
reset();
}
lastDocRequested = doc;
if (atDoc < doc) {
atDoc = docs.advance(doc);
}
if (atDoc > doc) {
// term doesn't match this document... either because we hit the
// end, or because the next doc is after this doc.
return 0;
}
// a match!
return docs.freq();
} catch (IOException e) {
throw new RuntimeException("caught exception in function "+description()+" : doc="+doc, e);
}
}
};
}
}