/*
* 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.prefs.impl;
import java.util.*;
import org.apache.felix.prefs.*;
import org.osgi.framework.*;
import org.osgi.service.log.LogService;
import org.osgi.service.prefs.BackingStoreException;
import org.osgi.service.prefs.PreferencesService;
import org.osgi.util.tracker.ServiceTracker;
/**
* This activator registers itself as a service factory for the
* preferences service.
*/
public class PreferencesManager
implements BundleActivator,
BundleListener,
ServiceFactory,
BackingStoreManager {
/**
* The map of already created services. For each client bundle
* a new service is created.
*/
protected final Map services = new HashMap();
/** The bundle context. */
protected BundleContext context;
/** The backing store service tracker. */
protected ServiceTracker storeTracker;
/** The service tracker for the log service. */
protected ServiceTracker logTracker;
/** The default store which is used if no service can be found. */
protected BackingStore defaultStore;
/** Tracking count for the store tracker to detect changes. */
protected int storeTrackingCount = -1;
/**
* @see org.osgi.framework.BundleListener#bundleChanged(org.osgi.framework.BundleEvent)
*/
public void bundleChanged(final BundleEvent event) {
if (event.getType() == BundleEvent.UNINSTALLED) {
final Long bundleId = new Long(event.getBundle().getBundleId());
synchronized (this.services) {
try {
final BackingStore store = this.getStore();
// Only in the case we're already being stopped, this situation could occur, see FELIX-3334
if (store != null) {
store.remove(bundleId);
}
}
catch (final BackingStoreException ignore) {
// we ignore this for now
}
this.services.remove(bundleId);
}
}
}
/**
* @see org.osgi.framework.BundleActivator#start(org.osgi.framework.BundleContext)
*/
public void start(final BundleContext context) throws Exception {
this.context = context;
// track the log service using a ServiceTracker
this.logTracker = new ServiceTracker(context, LogService.class.getName(), null);
this.logTracker.open();
// create the tracker for our backing store
this.storeTracker = new ServiceTracker(context, BackingStore.class.getName(), null);
this.storeTracker.open();
// register this activator as a bundle lister
context.addBundleListener(this);
// finally register the service factory for the preferences service
context.registerService(PreferencesService.class.getName(), this, null);
}
/**
* @see org.osgi.framework.BundleActivator#stop(org.osgi.framework.BundleContext)
*/
public void stop(final BundleContext context) throws Exception {
// if we get stopped, we should save all in memory representations
synchronized (this.services) {
final Iterator i = this.services.values().iterator();
while (i.hasNext()) {
final PreferencesServiceImpl service = (PreferencesServiceImpl) i.next();
this.save(service);
}
this.services.clear();
}
// stop tracking store service
if (this.storeTracker != null) {
this.storeTracker.close();
this.storeTracker = null;
}
this.defaultStore = null;
// stop tracking log service
if (this.logTracker != null) {
this.logTracker.close();
this.logTracker = null;
}
this.context = null;
}
/**
* @see org.osgi.framework.ServiceFactory#getService(org.osgi.framework.Bundle, org.osgi.framework.ServiceRegistration)
*/
public Object getService(final Bundle bundle, final ServiceRegistration reg) {
final Long bundleId = new Long(bundle.getBundleId());
synchronized (this.services) {
PreferencesServiceImpl service;
// do we already have created a service for this bundle?
service = (PreferencesServiceImpl) this.services.get(bundleId);
if (service == null) {
// create a new service instance
service = new PreferencesServiceImpl(bundleId, this);
this.services.put(bundleId, service);
}
return service;
}
}
/**
* @see org.osgi.framework.ServiceFactory#ungetService(org.osgi.framework.Bundle, org.osgi.framework.ServiceRegistration, java.lang.Object)
*/
public void ungetService(final Bundle bundle, final ServiceRegistration reg, final Object s) {
final Long bundleId = new Long(bundle.getBundleId());
// we save all the preferences
synchronized (this.services) {
final PreferencesServiceImpl service = (PreferencesServiceImpl) this.services.get(bundleId);
if (service != null) {
this.save(service);
}
}
}
/**
* Save all preferences for this service.
*
* @param service
*/
protected void save(final PreferencesServiceImpl service) {
final Iterator i = service.getAllPreferences().iterator();
while (i.hasNext()) {
final PreferencesImpl prefs = (PreferencesImpl) i.next();
try {
this.getStore().store(prefs);
}
catch (final BackingStoreException ignore) {
// we ignore this
}
}
}
protected void log(final int level, final String message, final Throwable t) {
final LogService log = (LogService) this.logTracker.getService();
if (log != null) {
log.log(level, message, t);
return;
}
}
/**
* @see org.apache.felix.prefs.BackingStoreManager#getStore()
*/
public BackingStore getStore() throws BackingStoreException {
BackingStore service = null;
ServiceTracker storeTracker = this.storeTracker;
// Only possible if we're not stopped already...
if (storeTracker != null) {
// has the service changed?
int currentCount = storeTracker.getTrackingCount();
service = (BackingStore) storeTracker.getService();
if (service != null && this.storeTrackingCount < currentCount) {
this.storeTrackingCount = currentCount;
this.cleanupStore(service);
}
if (service == null) {
// no service available use default store
if (this.defaultStore == null) {
synchronized (this) {
if (this.defaultStore == null) {
this.defaultStore = new DataFileBackingStoreImpl(this.context);
this.cleanupStore(this.defaultStore);
}
}
}
service = this.defaultStore;
}
}
if (service == null) {
// (still) no service available; cannot fulfill this request...
throw new BackingStoreException("No backing store!");
}
return service;
}
/**
* Clean up the store and remove preferences for deleted bundles.
*
* @param store
*/
protected void cleanupStore(final BackingStore store) {
// check which bundles are available
final Long[] availableBundleIds = store.availableBundles();
// now check the bundles, for which we have preferences, if they are still
// in service and delete the preferences where the bundles are out of service.
// we synchronize on services in order to get not disturbed by a bundle event
synchronized (this.services) {
for (int i = 0; i < availableBundleIds.length; i++) {
final Long bundleId = availableBundleIds[i];
final Bundle bundle = this.context.getBundle(bundleId.longValue());
if (bundle == null || bundle.getState() == Bundle.UNINSTALLED) {
try {
store.remove(bundleId);
}
catch (final BackingStoreException ignore) {
// we ignore this for now
}
}
}
}
}
}