/*
* 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.AtomicReaderContext;
import org.apache.lucene.index.NumericDocValues;
import org.apache.lucene.queries.function.FunctionValues;
import org.apache.lucene.queries.function.ValueSource;
import org.apache.lucene.queries.function.docvalues.FloatDocValues;
import org.apache.lucene.search.IndexSearcher;
import org.apache.lucene.search.similarities.TFIDFSimilarity;
import java.io.IOException;
import java.util.Map;
/**
* Function that returns {@link TFIDFSimilarity#decodeNormValue(byte)}
* for every document.
* <p>
* Note that the configured Similarity for the field must be
* a subclass of {@link TFIDFSimilarity}
* @lucene.internal */
public class NormValueSource extends ValueSource {
protected final String field;
public NormValueSource(String field) {
this.field = field;
}
public String name() {
return "norm";
}
@Override
public String description() {
return name() + '(' + field + ')';
}
@Override
public void createWeight(Map context, IndexSearcher searcher) throws IOException {
context.put("searcher",searcher);
}
@Override
public FunctionValues getValues(Map context, AtomicReaderContext readerContext) throws IOException {
IndexSearcher searcher = (IndexSearcher)context.get("searcher");
final TFIDFSimilarity similarity = IDFValueSource.asTFIDF(searcher.getSimilarity(), field);
if (similarity == null) {
throw new UnsupportedOperationException("requires a TFIDFSimilarity (such as DefaultSimilarity)");
}
final NumericDocValues norms = readerContext.reader().getNormValues(field);
if (norms == null) {
return new ConstDoubleDocValues(0.0, this);
}
return new FloatDocValues(this) {
@Override
public float floatVal(int doc) {
return similarity.decodeNormValue((byte)norms.get(doc));
}
};
}
@Override
public boolean equals(Object o) {
if (this.getClass() != o.getClass()) return false;
return this.field.equals(((NormValueSource)o).field);
}
@Override
public int hashCode() {
return this.getClass().hashCode() + field.hashCode();
}
}