Java tutorial
/* * Licensed to Elasticsearch under one or more contributor * license agreements. See the NOTICE file distributed with * this work for additional information regarding copyright * ownership. Elasticsearch 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.elasticsearch.index.cache.query.parser.resident; import com.google.common.cache.Cache; import com.google.common.cache.CacheBuilder; import org.apache.lucene.queryparser.classic.QueryParserSettings; import org.apache.lucene.search.Query; import org.elasticsearch.ElasticsearchException; import org.elasticsearch.common.inject.Inject; import org.elasticsearch.common.settings.Settings; import org.elasticsearch.common.unit.TimeValue; import org.elasticsearch.index.AbstractIndexComponent; import org.elasticsearch.index.Index; import org.elasticsearch.index.cache.query.parser.QueryParserCache; import org.elasticsearch.index.settings.IndexSettings; import java.util.concurrent.TimeUnit; /** * A small (by default) query parser cache mainly to not parse the same query string several times * if several shards exists on the same node. */ public class ResidentQueryParserCache extends AbstractIndexComponent implements QueryParserCache { private final Cache<QueryParserSettings, Query> cache; private volatile int maxSize; private volatile TimeValue expire; @Inject public ResidentQueryParserCache(Index index, @IndexSettings Settings indexSettings) { super(index, indexSettings); this.maxSize = componentSettings.getAsInt("max_size", 100); this.expire = componentSettings.getAsTime("expire", null); logger.debug("using [resident] query cache with max_size [{}], expire [{}]", maxSize, expire); CacheBuilder cacheBuilder = CacheBuilder.newBuilder().maximumSize(maxSize); if (expire != null) { cacheBuilder.expireAfterAccess(expire.nanos(), TimeUnit.NANOSECONDS); } this.cache = cacheBuilder.build(); } @Override public Query get(QueryParserSettings queryString) { return cache.getIfPresent(queryString); } @Override public void put(QueryParserSettings queryString, Query query) { if (queryString.isCacheable()) { cache.put(queryString, query); } } @Override public void clear() { cache.invalidateAll(); } @Override public void close() throws ElasticsearchException { cache.invalidateAll(); } }