/*
* 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.jackrabbit.core.query.lucene;
import java.io.IOException;
import org.apache.lucene.search.SortComparatorSource;
import org.apache.lucene.search.ScoreDocComparator;
import org.apache.lucene.search.ScoreDoc;
import org.apache.lucene.index.IndexReader;
import org.apache.jackrabbit.spi.NameFactory;
import org.apache.jackrabbit.spi.commons.name.NameFactoryImpl;
import org.apache.jackrabbit.spi.commons.conversion.IllegalNameException;
/**
* <code>LengthSortComparator</code> implements a sort comparator source that
* sorts on the length of property values.
*/
public class LengthSortComparator implements SortComparatorSource {
private static final long serialVersionUID = 2513564768671391632L;
/**
* The index internal namespace mappings.
*/
private final NamespaceMappings nsMappings;
public LengthSortComparator(NamespaceMappings nsMappings) {
this.nsMappings = nsMappings;
}
/**
* Creates a new comparator.
*
* @param reader the current index reader.
* @param fieldname the name of the property to sort on. This is the string
* representation of {@link org.apache.jackrabbit.spi.Name
* Name}.
* @return the score doc comparator.
* @throws IOException if an error occurs while reading from the index.
*/
public ScoreDocComparator newComparator(IndexReader reader,
String fieldname)
throws IOException {
NameFactory factory = NameFactoryImpl.getInstance();
try {
return new Comparator(reader,
nsMappings.translateName(factory.create(fieldname)));
} catch (IllegalNameException e) {
throw Util.createIOException(e);
}
}
private final class Comparator extends AbstractScoreDocComparator {
/**
* The term look ups of the index segments.
*/
protected final SharedFieldCache.ValueIndex[] indexes;
public Comparator(IndexReader reader,
String propertyName) throws IOException {
super(reader);
this.indexes = new SharedFieldCache.ValueIndex[readers.size()];
String namedLength = FieldNames.createNamedValue(propertyName, "");
for (int i = 0; i < readers.size(); i++) {
IndexReader r = readers.get(i);
indexes[i] = SharedFieldCache.INSTANCE.getValueIndex(
r, FieldNames.PROPERTY_LENGTHS,
namedLength, LengthSortComparator.this);
}
}
public Comparable sortValue(ScoreDoc i) {
int idx = readerIndex(i.doc);
return indexes[idx].getValue(i.doc - starts[idx]);
}
}
}