/*
* 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.benchmark.quality.utils;
import java.io.IOException;
import java.util.ArrayList;
import java.util.List;
import org.apache.lucene.index.FieldInfo;
import org.apache.lucene.index.StoredFieldVisitor;
import org.apache.lucene.search.IndexSearcher;
/**
* Utility: extract doc names from an index
*/
public class DocNameExtractor {
private final String docNameField;
/**
* Constructor for DocNameExtractor.
* @param docNameField name of the stored field containing the doc name.
*/
public DocNameExtractor (final String docNameField) {
this.docNameField = docNameField;
}
/**
* Extract the name of the input doc from the index.
* @param searcher access to the index.
* @param docid ID of doc whose name is needed.
* @return the name of the input doc as extracted from the index.
* @throws IOException if cannot extract the doc name from the index.
*/
public String docName(IndexSearcher searcher, int docid) throws IOException {
final List<String> name = new ArrayList<>();
searcher.getIndexReader().document(docid, new StoredFieldVisitor() {
@Override
public void stringField(FieldInfo fieldInfo, String value) {
name.add(value);
}
@Override
public Status needsField(FieldInfo fieldInfo) {
if (!name.isEmpty()) {
return Status.STOP;
} else if (fieldInfo.name.equals(docNameField)) {
return Status.YES;
} else {
return Status.NO;
}
}
});
if (name.size() != 0) {
return name.get(0);
} else {
return null;
}
}
}