package org.apache.mahout.text;
/*
* 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.
*/
import org.apache.lucene.search.CollectionStatistics;
import org.apache.lucene.search.IndexSearcher;
import java.io.IOException;
/**
* Utility for checking if a field exist in a Lucene index.
*/
public class LuceneIndexHelper {
private LuceneIndexHelper() {
}
public static void fieldShouldExistInIndex(IndexSearcher searcher, String field) throws IOException {
CollectionStatistics idFieldStatistics = searcher.collectionStatistics(field);
if (idFieldStatistics.docCount() == 0) {
throw new IllegalArgumentException("Field '" + field + "' does not exist in the index");
}
}
}