/**
* 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.solr.search.function;
import org.apache.lucene.index.*;
import org.apache.lucene.search.DocIdSetIterator;
import org.apache.lucene.search.Searcher;
import org.apache.lucene.search.Similarity;
import org.apache.lucene.util.BytesRef;
import org.apache.solr.common.SolrException;
import org.apache.solr.search.SolrIndexReader;
import org.apache.solr.util.ByteUtils;
import java.io.IOException;
import java.util.Map;
/** @internal */
public class IDFValueSource extends DocFreqValueSource {
public IDFValueSource(String field, String val, String indexedField, BytesRef indexedBytes) {
super(field, val, indexedField, indexedBytes);
}
@Override
public String name() {
return "idf";
}
@Override
public DocValues getValues(Map context, IndexReader reader) throws IOException {
Searcher searcher = (Searcher)context.get("searcher");
Similarity sim = searcher.getSimilarity();
// todo: we need docFreq that takes a BytesRef
String strVal = ByteUtils.UTF8toUTF16(indexedBytes);
int docfreq = searcher.docFreq(new Term(indexedField, strVal));
float idf = sim.idf(docfreq, searcher.maxDoc());
return new ConstDoubleDocValues(idf, this);
}
}