| /* |
| * Licensed to the Apache Software Foundation (ASF) under one or more |
| * contributor license agreements. 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. For additional information regarding |
| * copyright in this work, please see the NOTICE file in the top level |
| * directory of this distribution. |
| */ |
| |
| package org.apache.roller.weblogger.util.cache; |
| |
| import java.util.HashMap; |
| import java.util.HashSet; |
| import java.util.Map; |
| import java.util.Set; |
| import org.apache.commons.logging.Log; |
| import org.apache.commons.logging.LogFactory; |
| import org.apache.roller.weblogger.config.WebloggerConfig; |
| import org.apache.roller.weblogger.pojos.WeblogBookmark; |
| import org.apache.roller.weblogger.pojos.WeblogEntryComment; |
| import org.apache.roller.weblogger.pojos.WeblogBookmarkFolder; |
| import org.apache.roller.weblogger.pojos.User; |
| import org.apache.roller.weblogger.pojos.WeblogCategory; |
| import org.apache.roller.weblogger.pojos.WeblogEntry; |
| import org.apache.roller.weblogger.pojos.WeblogTemplate; |
| import org.apache.roller.weblogger.pojos.Weblog; |
| |
| |
| /** |
| * A governing class for Roller cache objects. |
| * |
| * The purpose of the CacheManager is to provide a level of abstraction between |
| * classes that use a cache and the implementations of a cache. This allows |
| * us to create easily pluggable cache implementations. |
| * |
| * The other purpose is to provide a single interface for interacting with all |
| * Roller caches at the same time. This is beneficial because as data |
| * changes in the system we often need to notify all caches that some part of |
| * their cached data needs to be invalidated, and the CacheManager makes that |
| * process easier. |
| */ |
| public final class CacheManager { |
| |
| private static Log log = LogFactory.getLog(CacheManager.class); |
| |
| private static final String DEFAULT_FACTORY = |
| "org.apache.roller.weblogger.util.cache.ExpiringLRUCacheFactoryImpl"; |
| |
| // a reference to the cache factory in use |
| private static CacheFactory cacheFactory = null; |
| |
| // a set of all registered cache handlers |
| private static Set<CacheHandler> cacheHandlers = new HashSet<>(); |
| |
| // a map of all registered caches |
| private static Map<String, Cache> caches = new HashMap<>(); |
| |
| |
| static { |
| // lookup what cache factory we want to use |
| String classname = WebloggerConfig.getProperty("cache.defaultFactory"); |
| |
| // use reflection to instantiate our factory class |
| try { |
| Class factoryClass = Class.forName(classname); |
| cacheFactory = (CacheFactory) factoryClass.newInstance(); |
| } catch(ClassCastException cce) { |
| log.error("It appears that your factory does not implement "+ |
| "the CacheFactory interface",cce); |
| } catch(Exception e) { |
| log.error("Unable to instantiate cache factory ["+classname+"]"+ |
| " falling back on default", e); |
| } |
| |
| if(cacheFactory == null) { |
| try { |
| // hmm ... failed to load the specified cache factory |
| // lets try our default |
| Class factoryClass = Class.forName(DEFAULT_FACTORY); |
| cacheFactory = (CacheFactory) factoryClass.newInstance(); |
| } catch(Exception e) { |
| log.fatal("Failed to instantiate a cache factory", e); |
| throw new RuntimeException(e); |
| } |
| } |
| |
| log.info("Cache Manager Initialized."); |
| log.info("Cache Factory = "+cacheFactory.getClass().getName()); |
| |
| |
| // add custom handlers |
| String customHandlers = WebloggerConfig.getProperty("cache.customHandlers"); |
| if(customHandlers != null && !customHandlers.isBlank()) { |
| |
| String[] cHandlers = customHandlers.split(","); |
| for (String cHandler : cHandlers) { |
| // use reflection to instantiate the handler class |
| try { |
| Class handlerClass = Class.forName(cHandler); |
| CacheHandler customHandler = |
| (CacheHandler) handlerClass.newInstance(); |
| |
| cacheHandlers.add(customHandler); |
| } catch(ClassCastException cce) { |
| log.error("It appears that your handler does not implement "+ |
| "the CacheHandler interface",cce); |
| } catch(Exception e) { |
| log.error("Unable to instantiate cache handler ["+cHandler+"]", e); |
| } |
| } |
| } |
| } |
| |
| |
| // a non-instantiable class |
| private CacheManager() {} |
| |
| |
| /** |
| * Ask the CacheManager to construct a cache. |
| * |
| * Normally the CacheManager will use whatever CacheFactory has been |
| * chosen for the system via the cache.defaultFactory property. |
| * However, it is possible to override the use of the default factory by |
| * supplying a "factory" property to this method. The value should |
| * be the full classname for the factory you want to use for constructing |
| * the cache. |
| * |
| * example: |
| * factory -> org.apache.roller.weblogger.util.cache.LRUCacheFactoryImpl |
| * |
| * This allows Roller admins the ability to choose a caching strategy to |
| * use for the whole system, but override it in certain places where they |
| * see fit. It also allows users to write their own caching modifications |
| * and have them used only by specific caches. |
| */ |
| public static Cache constructCache(CacheHandler handler, Map properties) { |
| |
| log.debug("Constructing new cache with props "+properties); |
| |
| Cache cache = null; |
| |
| if(properties != null && properties.containsKey("factory")) { |
| // someone wants a custom cache instance |
| String classname = (String) properties.get("factory"); |
| |
| try { |
| // use reflection to instantiate the factory class |
| Class factoryClass = Class.forName(classname); |
| CacheFactory factory = (CacheFactory) factoryClass.newInstance(); |
| |
| // now ask for a new cache |
| cache = factory.constructCache(properties); |
| } catch(ClassCastException cce) { |
| log.error("It appears that your factory ["+classname+ |
| "] does not implement the CacheFactory interface",cce); |
| } catch(Exception e) { |
| log.error("Unable to instantiate cache factory ["+classname+ |
| "] falling back on default", e); |
| } |
| } |
| |
| if(cache == null) { |
| // ask our default cache factory for a new cache instance |
| cache = cacheFactory.constructCache(properties); |
| } |
| |
| if(cache != null) { |
| caches.put(cache.getId(), cache); |
| |
| // register the handler for this new cache |
| if(handler != null) { |
| cacheHandlers.add(handler); |
| } |
| } |
| |
| return cache; |
| } |
| |
| |
| /** |
| * Register a CacheHandler to listen for object invalidations. |
| * |
| * This is here so that it's possible to to add classes which would respond |
| * to object invalidations without necessarily having to create a cache. |
| * |
| * An example would be a handler designed to notify other machines in a |
| * cluster when an object has been invalidated, or possibly the search |
| * index management classes are interested in knowing when objects are |
| * invalidated. |
| */ |
| public static void registerHandler(CacheHandler handler) { |
| |
| log.debug("Registering handler "+handler); |
| |
| if(handler != null) { |
| cacheHandlers.add(handler); |
| } |
| } |
| |
| |
| public static void invalidate(WeblogEntry entry) { |
| |
| log.debug("invalidating entry = "+entry.getAnchor()); |
| for (CacheHandler handler : cacheHandlers) { |
| handler.invalidate(entry); |
| } |
| } |
| |
| |
| public static void invalidate(Weblog website) { |
| |
| log.debug("invalidating website = "+website.getHandle()); |
| for (CacheHandler handler : cacheHandlers) { |
| handler.invalidate(website); |
| } |
| } |
| |
| |
| public static void invalidate(WeblogBookmark bookmark) { |
| |
| log.debug("invalidating bookmark = "+bookmark.getId()); |
| for (CacheHandler handler : cacheHandlers) { |
| handler.invalidate(bookmark); |
| } |
| } |
| |
| |
| public static void invalidate(WeblogBookmarkFolder folder) { |
| |
| log.debug("invalidating folder = "+folder.getId()); |
| for (CacheHandler handler : cacheHandlers) { |
| handler.invalidate(folder); |
| } |
| } |
| |
| |
| public static void invalidate(WeblogEntryComment comment) { |
| |
| log.debug("invalidating comment = "+comment.getId()); |
| for (CacheHandler handler : cacheHandlers) { |
| handler.invalidate(comment); |
| } |
| } |
| |
| |
| public static void invalidate(User user) { |
| |
| log.debug("invalidating user = "+user.getUserName()); |
| for (CacheHandler handler : cacheHandlers) { |
| handler.invalidate(user); |
| } |
| } |
| |
| |
| public static void invalidate(WeblogCategory category) { |
| |
| log.debug("invalidating category = " + category.getId()); |
| for (CacheHandler handler : cacheHandlers) { |
| handler.invalidate(category); |
| } |
| } |
| |
| |
| public static void invalidate(WeblogTemplate template) { |
| log.debug("invalidating template = " + template.getId()); |
| for (CacheHandler handler : cacheHandlers) { |
| handler.invalidate(template); |
| } |
| } |
| |
| |
| /** |
| * Flush the entire cache system. |
| */ |
| public static void clear() { |
| for (Cache cache : caches.values()) { |
| cache.clear(); |
| } |
| } |
| |
| |
| /** |
| * Flush a single cache. |
| */ |
| public static void clear(String cacheId) { |
| Cache cache = caches.get(cacheId); |
| if(cache != null) { |
| cache.clear(); |
| } |
| } |
| |
| |
| /** |
| * Compile stats from all registered caches. |
| * |
| * This is basically a hacky version of instrumentation which is being |
| * thrown in because we don't have a full instrumentation strategy yet. |
| * This is here with the full expectation that it will be replaced by |
| * something a bit more elaborate, like JMX. |
| */ |
| public static Map<String, Map<String, Object>> getStats() { |
| Map<String, Map<String, Object>> allStats = new HashMap<>(); |
| for (Cache cache : caches.values()) { |
| allStats.put(cache.getId(), cache.getStats()); |
| } |
| return allStats; |
| } |
| |
| |
| /** |
| * Place to do any cleanup tasks for cache system. |
| */ |
| public static void shutdown() { |
| // no-op |
| } |
| |
| } |