/*
* 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.search;
import java.io.IOException;
import java.util.concurrent.ExecutorService; // javadocs
import org.apache.lucene.index.IndexReader;
import org.apache.lucene.index.IndexWriter; // javadocs
import org.apache.lucene.index.IndexWriterConfig; // javadocs
import org.apache.lucene.search.similarities.Similarity; // javadocs
/**
* Factory class used by {@link SearcherManager} to
* create new IndexSearchers. The default implementation just creates
* an IndexSearcher with no custom behavior:
*
* <pre class="prettyprint">
* public IndexSearcher newSearcher(IndexReader r) throws IOException {
* return new IndexSearcher(r);
* }
* </pre>
*
* You can pass your own factory instead if you want custom behavior, such as:
* <ul>
* <li>Setting a custom scoring model: {@link IndexSearcher#setSimilarity(Similarity)}
* <li>Parallel per-segment search: {@link IndexSearcher#IndexSearcher(IndexReader, ExecutorService)}
* <li>Return custom subclasses of IndexSearcher (for example that implement distributed scoring)
* <li>Run queries to warm your IndexSearcher before it is used. Note: when using near-realtime search
* you may want to also {@link IndexWriterConfig#setMergedSegmentWarmer(IndexWriter.IndexReaderWarmer)} to warm
* newly merged segments in the background, outside of the reopen path.
* </ul>
* @lucene.experimental
*/
public class SearcherFactory {
/**
* Returns a new IndexSearcher over the given reader.
* @param reader the reader to create a new searcher for
* @param previousReader the reader previously used to create a new searcher.
* This can be <code>null</code> if unknown or if the given reader is the initially opened reader.
* If this reader is non-null it can be used to find newly opened segments compared to the new reader to warm
* the searcher up before returning.
*/
public IndexSearcher newSearcher(IndexReader reader, IndexReader previousReader) throws IOException {
return new IndexSearcher(reader);
}
}