/* * Copyright 2015 Pawan Dubey. * * Licensed 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 com.pawandubey.griffin.cache; import static com.pawandubey.griffin.Data.fileQueue; import static com.pawandubey.griffin.Data.tags; import static com.pawandubey.griffin.DirectoryCrawler.FILE_SEPARATOR; import static com.pawandubey.griffin.DirectoryCrawler.ROOT_DIRECTORY; import java.io.File; import java.util.concurrent.ConcurrentMap; import org.mapdb.DB; import org.mapdb.DBMaker; /** * * @author Pawan Dubey [email protected] */ public class Cacher { public static final String CACHE_PATH = ROOT_DIRECTORY + FILE_SEPARATOR + "cache.db"; public final DB db; /** * Creates a new Cacher with a file database in the ROOT_FOLDER with * asyncWriteEnabled and transactionDisabled with JVM shutdown hook. */ public Cacher() { db = DBMaker.newFileDB(new File(CACHE_PATH)) .asyncWriteEnable() .closeOnJvmShutdown() .transactionDisable() .mmapFileEnableIfSupported() .make(); } /** * Creates a cache of everything other than the fileQueue. */ public void cacheTaggedParsables() { ConcurrentMap<String, Object> mainMap = db.getHashMap("mainMap"); mainMap.put("tags", tags); db.commit(); } /** * Caches the fileQueue before it goes for parsing. */ public void cacheFileQueue() { ConcurrentMap<String, Object> mainMap = db.getHashMap("mainMap"); mainMap.put("fileQueue", fileQueue); } /** * Fetches and returns the map from the cache. * * @return the cached map. */ public ConcurrentMap<String, Object> readFromCacheIfExists() { return db.getHashMap("mainMap"); } /** * Checks if the cache exists by checking if the map contains any elements. * This is necessary because the getHashMap method creates a new map if not * present instead of returning null. * * @return the HashMap */ public boolean cacheExists() { return !db.getHashMap("mainMap").isEmpty(); } }