| /* |
| * 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.felix.cm.impl.persistence; |
| |
| |
| import java.io.IOException; |
| import java.util.ArrayList; |
| import java.util.Collection; |
| import java.util.Collections; |
| import java.util.Dictionary; |
| import java.util.Enumeration; |
| import java.util.HashMap; |
| import java.util.HashSet; |
| import java.util.List; |
| import java.util.Map; |
| import java.util.Set; |
| import java.util.concurrent.locks.Lock; |
| import java.util.concurrent.locks.ReadWriteLock; |
| import java.util.concurrent.locks.ReentrantReadWriteLock; |
| |
| import org.apache.felix.cm.PersistenceManager; |
| import org.apache.felix.cm.impl.CaseInsensitiveDictionary; |
| import org.apache.felix.cm.impl.SimpleFilter; |
| import org.osgi.framework.Constants; |
| import org.osgi.service.cm.ConfigurationAdmin; |
| |
| |
| /** |
| * The <code>CachingPersistenceManagerProxy</code> adds a caching layer to the |
| * underlying actual {@link PersistenceManager} implementation. All API calls |
| * are also (or primarily) routed through a local cache of dictionaries indexed |
| * by the <code>service.pid</code>. |
| */ |
| public class CachingPersistenceManagerProxy implements ExtPersistenceManager |
| { |
| |
| /** The actual PersistenceManager */ |
| private final PersistenceManager pm; |
| |
| /** Cached dictionaries */ |
| private final Map<String, CaseInsensitiveDictionary> cache = new HashMap<>(); |
| |
| /** Protecting lock */ |
| private final ReadWriteLock globalLock = new ReentrantReadWriteLock(); |
| |
| /** |
| * Indicates whether the getDictionaries method has already been called |
| * and the cache is complete with respect to the contents of the underlying |
| * persistence manager. |
| */ |
| private volatile boolean fullyLoaded; |
| |
| /** Factory configuration cache. */ |
| private final Map<String, Set<String>> factoryConfigCache = new HashMap<>(); |
| |
| /** |
| * Creates a new caching layer for the given actual {@link PersistenceManager}. |
| * @param pm The actual {@link PersistenceManager} |
| */ |
| public CachingPersistenceManagerProxy( final PersistenceManager pm ) |
| { |
| this.pm = pm; |
| } |
| |
| @Override |
| public PersistenceManager getDelegatee() |
| { |
| return pm; |
| } |
| |
| /** |
| * Remove the configuration with the given PID. This implementation removes |
| * the entry from the cache before calling the underlying persistence |
| * manager. |
| */ |
| @Override |
| public void delete( final String pid ) throws IOException |
| { |
| Lock lock = globalLock.writeLock(); |
| try |
| { |
| lock.lock(); |
| final Dictionary props = cache.remove( pid ); |
| if ( props != null ) |
| { |
| final String factoryPid = (String)props.get(ConfigurationAdmin.SERVICE_FACTORYPID); |
| if ( factoryPid != null ) |
| { |
| final Set<String> factoryPids = this.factoryConfigCache.get(factoryPid); |
| if ( factoryPids != null ) |
| { |
| factoryPids.remove(pid); |
| if ( factoryPids.isEmpty() ) |
| { |
| this.factoryConfigCache.remove(factoryPid); |
| } |
| } |
| } |
| } |
| pm.delete(pid); |
| } |
| finally |
| { |
| lock.unlock(); |
| } |
| } |
| |
| |
| /** |
| * Checks whether a dictionary with the given pid exists. First checks for |
| * the existence in the cache. If not in the cache the underlying |
| * persistence manager is asked. |
| */ |
| @Override |
| public boolean exists( final String pid ) |
| { |
| Lock lock = globalLock.readLock(); |
| try |
| { |
| lock.lock(); |
| return cache.containsKey( pid ) || ( !fullyLoaded && pm.exists( pid ) ); |
| } |
| finally |
| { |
| lock.unlock(); |
| } |
| } |
| |
| |
| /** |
| * Returns an <code>Enumeration</code> of <code>Dictionary</code> objects |
| * representing the configurations stored in the underlying persistence |
| * managers. The dictionaries returned are guaranteed to contain the |
| * <code>service.pid</code> property. |
| * <p> |
| * Note, that each call to this method will return new dictionary objects. |
| * That is modifying the contents of a dictionary returned from this method |
| * has no influence on the dictionaries stored in the cache. |
| */ |
| @Override |
| public Enumeration getDictionaries() throws IOException |
| { |
| return Collections.enumeration(getDictionaries( null )); |
| } |
| |
| private final CaseInsensitiveDictionary cache(final Dictionary props) |
| { |
| final String pid = (String) props.get( Constants.SERVICE_PID ); |
| CaseInsensitiveDictionary dict = null; |
| if ( pid != null ) |
| { |
| dict = cache.get(pid); |
| if ( dict == null ) |
| { |
| dict = new CaseInsensitiveDictionary(props); |
| cache.put( pid, dict ); |
| final String factoryPid = (String)props.get(ConfigurationAdmin.SERVICE_FACTORYPID); |
| if ( factoryPid != null ) |
| { |
| Set<String> factoryPids = this.factoryConfigCache.get(factoryPid); |
| if ( factoryPids == null ) |
| { |
| factoryPids = new HashSet<>(); |
| this.factoryConfigCache.put(factoryPid, factoryPids); |
| } |
| factoryPids.add(pid); |
| } |
| } |
| } |
| return dict; |
| } |
| |
| @Override |
| public Collection<Dictionary> getDictionaries( final SimpleFilter filter ) throws IOException |
| { |
| Lock lock = globalLock.readLock(); |
| try |
| { |
| lock.lock(); |
| // if not fully loaded, call back to the underlying persistence |
| // manager and cache all dictionaries whose service.pid is set |
| if ( !fullyLoaded ) |
| { |
| lock.unlock(); |
| lock = globalLock.writeLock(); |
| lock.lock(); |
| if ( !fullyLoaded ) |
| { |
| Enumeration fromPm = pm.getDictionaries(); |
| while ( fromPm.hasMoreElements() ) |
| { |
| Dictionary next = (Dictionary) fromPm.nextElement(); |
| this.cache(next); |
| } |
| this.fullyLoaded = true; |
| } |
| } |
| |
| // Deep copy the configuration to avoid any threading issue |
| final List<Dictionary> configs = new ArrayList<>(); |
| for (final Dictionary d : cache.values()) |
| { |
| if ( d.get( Constants.SERVICE_PID ) != null && ( filter == null || filter.matches( d ) ) ) |
| { |
| configs.add( new CaseInsensitiveDictionary( d ) ); |
| } |
| } |
| return configs; |
| } |
| finally |
| { |
| lock.unlock(); |
| } |
| } |
| |
| |
| /** |
| * Returns the dictionary for the given PID or <code>null</code> if no |
| * such dictionary is stored by the underlying persistence manager. This |
| * method caches the returned dictionary for future use after retrieving |
| * if from the persistence manager. |
| * <p> |
| * Note, that each call to this method will return new dictionary instance. |
| * That is modifying the contents of a dictionary returned from this method |
| * has no influence on the dictionaries stored in the cache. |
| */ |
| @Override |
| public Dictionary load( final String pid ) throws IOException |
| { |
| Lock lock = globalLock.readLock(); |
| try |
| { |
| lock.lock(); |
| CaseInsensitiveDictionary loaded = cache.get( pid ); |
| if ( loaded == null && !fullyLoaded ) |
| { |
| lock.unlock(); |
| lock = globalLock.writeLock(); |
| lock.lock(); |
| loaded = cache.get( pid ); |
| if ( loaded == null ) |
| { |
| final Dictionary props = pm.load( pid ); |
| if ( props != null ) |
| { |
| loaded = this.cache(props); |
| } |
| } |
| } |
| return loaded == null ? null : new CaseInsensitiveDictionary(loaded); |
| } |
| finally |
| { |
| lock.unlock(); |
| } |
| } |
| |
| |
| /** |
| * Stores the dictionary in the cache and in the underlying persistence |
| * manager. This method first calls the underlying persistence manager |
| * before updating the dictionary in the cache. |
| * <p> |
| * Note, that actually a copy of the dictionary is stored in the cache. That |
| * is subsequent modification to the given dictionary has no influence on |
| * the cached data. |
| */ |
| @Override |
| public void store( final String pid, final Dictionary properties ) throws IOException |
| { |
| final Lock lock = globalLock.writeLock(); |
| try |
| { |
| lock.lock(); |
| pm.store( pid, properties ); |
| this.cache.remove(pid); |
| this.cache(properties); |
| } |
| finally |
| { |
| lock.unlock(); |
| } |
| } |
| |
| @Override |
| public Set<String> getFactoryConfigurationPids(final List<String> targetedFactoryPids ) |
| throws IOException |
| { |
| final Set<String> pids = new HashSet<>(); |
| Lock lock = globalLock.readLock(); |
| try |
| { |
| lock.lock(); |
| if ( !this.fullyLoaded ) |
| { |
| lock.unlock(); |
| lock = globalLock.writeLock(); |
| lock.lock(); |
| if ( !this.fullyLoaded ) |
| { |
| final Enumeration fromPm = pm.getDictionaries(); |
| while ( fromPm.hasMoreElements() ) |
| { |
| Dictionary next = (Dictionary) fromPm.nextElement(); |
| this.cache(next); |
| } |
| this.fullyLoaded = true; |
| } |
| lock.unlock(); |
| lock = globalLock.readLock(); |
| lock.lock(); |
| } |
| for(final String targetFactoryPid : targetedFactoryPids) |
| { |
| final Set<String> cachedPids = this.factoryConfigCache.get(targetFactoryPid); |
| if ( cachedPids != null ) |
| { |
| pids.addAll(cachedPids); |
| } |
| } |
| } |
| finally |
| { |
| lock.unlock(); |
| } |
| return pids; |
| } |
| } |