/*
* 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 java.io.IOException;
import java.util.Map;
import org.apache.lucene.index.AtomicReaderContext;
import org.apache.lucene.index.BinaryDocValues;
import org.apache.lucene.index.IndexReader;
import org.apache.lucene.index.MultiFields;
import org.apache.lucene.index.ReaderUtil;
import org.apache.lucene.index.Terms;
import org.apache.lucene.index.TermsEnum;
import org.apache.lucene.queries.function.FunctionValues;
import org.apache.lucene.queries.function.docvalues.IntDocValues;
import org.apache.lucene.util.BytesRef;
import org.apache.lucene.util.packed.PackedInts;
/**
* Use a field value and find the Document Frequency within another field.
*
* @since solr 4.0
*/
public class JoinDocFreqValueSource extends FieldCacheSource {
public static final String NAME = "joindf";
protected final String qfield;
public JoinDocFreqValueSource(String field, String qfield) {
super(field);
this.qfield = qfield;
}
@Override
public String description() {
return NAME + "(" + field +":("+qfield+"))";
}
@Override
public FunctionValues getValues(Map context, AtomicReaderContext readerContext) throws IOException
{
final BinaryDocValues terms = cache.getTerms(readerContext.reader(), field, false, PackedInts.FAST);
final IndexReader top = ReaderUtil.getTopLevelContext(readerContext).reader();
Terms t = MultiFields.getTerms(top, qfield);
final TermsEnum termsEnum = t == null ? TermsEnum.EMPTY : t.iterator(null);
return new IntDocValues(this) {
@Override
public int intVal(int doc)
{
try {
final BytesRef term = terms.get(doc);
if (termsEnum.seekExact(term)) {
return termsEnum.docFreq();
} else {
return 0;
}
}
catch (IOException e) {
throw new RuntimeException("caught exception in function "+description()+" : doc="+doc, e);
}
}
};
}
@Override
public boolean equals(Object o) {
if (o.getClass() != JoinDocFreqValueSource.class) return false;
JoinDocFreqValueSource other = (JoinDocFreqValueSource)o;
if( !qfield.equals( other.qfield ) ) return false;
return super.equals(other);
}
@Override
public int hashCode() {
return qfield.hashCode() + super.hashCode();
}
}