/*
* 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.AtomicReader;
import org.apache.lucene.index.AtomicReaderContext;
import org.apache.lucene.index.CompositeReader;
import org.apache.lucene.index.IndexReader;
import org.apache.lucene.index.ReaderUtil;
import org.apache.lucene.index.SlowCompositeReaderWrapper;
import org.apache.lucene.index.SortedDocValues;
import org.apache.lucene.queries.function.FunctionValues;
import org.apache.lucene.queries.function.ValueSource;
import org.apache.lucene.queries.function.docvalues.IntDocValues;
import org.apache.lucene.search.FieldCache;
import org.apache.lucene.util.mutable.MutableValue;
import org.apache.lucene.util.mutable.MutableValueInt;
/**
* Obtains the ordinal of the field value from the default Lucene {@link org.apache.lucene.search.FieldCache} using getStringIndex().
* <br>
* The native lucene index order is used to assign an ordinal value for each field value.
* <br>Field values (terms) are lexicographically ordered by unicode value, and numbered starting at 1.
* <br>
* Example:<br>
* If there were only three field values: "apple","banana","pear"
* <br>then ord("apple")=1, ord("banana")=2, ord("pear")=3
* <p>
* WARNING: ord() depends on the position in an index and can thus change when other documents are inserted or deleted,
* or if a MultiSearcher is used.
* <br>WARNING: as of Solr 1.4, ord() and rord() can cause excess memory use since they must use a FieldCache entry
* at the top level reader, while sorting and function queries now use entries at the segment level. Hence sorting
* or using a different function query, in addition to ord()/rord() will double memory use.
*
*/
public class OrdFieldSource extends ValueSource {
protected final String field;
public OrdFieldSource(String field) {
this.field = field;
}
@Override
public String description() {
return "ord(" + field + ')';
}
// TODO: this is trappy? perhaps this query instead should make you pass a slow reader yourself?
@Override
public FunctionValues getValues(Map context, AtomicReaderContext readerContext) throws IOException {
final int off = readerContext.docBase;
final IndexReader topReader = ReaderUtil.getTopLevelContext(readerContext).reader();
final AtomicReader r = topReader instanceof CompositeReader
? new SlowCompositeReaderWrapper((CompositeReader)topReader)
: (AtomicReader) topReader;
final SortedDocValues sindex = FieldCache.DEFAULT.getTermsIndex(r, field);
return new IntDocValues(this) {
protected String toTerm(String readableValue) {
return readableValue;
}
@Override
public int intVal(int doc) {
return sindex.getOrd(doc+off);
}
@Override
public int ordVal(int doc) {
return sindex.getOrd(doc+off);
}
@Override
public int numOrd() {
return sindex.getValueCount();
}
@Override
public boolean exists(int doc) {
return sindex.getOrd(doc+off) != 0;
}
@Override
public ValueFiller getValueFiller() {
return new ValueFiller() {
private final MutableValueInt mval = new MutableValueInt();
@Override
public MutableValue getValue() {
return mval;
}
@Override
public void fillValue(int doc) {
mval.value = sindex.getOrd(doc);
mval.exists = mval.value!=0;
}
};
}
};
}
@Override
public boolean equals(Object o) {
return o != null && o.getClass() == OrdFieldSource.class && this.field.equals(((OrdFieldSource)o).field);
}
private static final int hcode = OrdFieldSource.class.hashCode();
@Override
public int hashCode() {
return hcode + field.hashCode();
}
}