Java tutorial
/* * 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; /** * A policy defining which filters should be cached. * * Implementations of this class must be thread-safe. * * @see UsageTrackingQueryCachingPolicy * @see LRUQueryCache * @lucene.experimental */ // TODO: add APIs for integration with IndexWriter.IndexReaderWarmer public interface QueryCachingPolicy { /** Callback that is called every time that a cached filter is used. * This is typically useful if the policy wants to track usage statistics * in order to make decisions. */ void onUse(Query query); /** Whether the given {@link Query} is worth caching. * This method will be called by the {@link QueryCache} to know whether to * cache. It will first attempt to load a {@link DocIdSet} from the cache. * If it is not cached yet and this method returns <tt>true</tt> then a * cache entry will be generated. Otherwise an uncached scorer will be * returned. */ boolean shouldCache(Query query) throws IOException; }