/*******************************************************************************
* Copyright (c) 1998, 2010 Oracle. All rights reserved.
*
* This program and the accompanying materials are made available under the
* terms of the Eclipse Public License v1.0 and Eclipse Distribution License v. 1.0
* which accompanies this distribution.
* The Eclipse Public License is available at http://www.eclipse.org/legal/epl-v10.html
* and the Eclipse Distribution License is available at
* http://www.eclipse.org/org/documents/edl-v10.php.
*
* Contributors:
* tware,mkeith - Initial OSGi support for JPA
* ssmith - Cleanup of activator/listener into this class
* dclarke - 20090916 - Added clearCachedProviders support
* ssmith - 20091126 - Bug 296010 - providers map not initialized before use
*
******************************************************************************/
package org.eclipse.persistence.javax.persistence.osgi;
import java.util.ArrayList;
import java.util.Hashtable;
import java.util.List;
import java.util.Map;
import java.util.logging.Level;
import java.util.logging.Logger;
import javax.persistence.spi.PersistenceProvider;
import javax.persistence.spi.PersistenceProviderResolver;
import javax.persistence.spi.PersistenceProviderResolverHolder;
import org.osgi.framework.BundleActivator;
import org.osgi.framework.BundleContext;
import org.osgi.framework.ServiceReference;
import org.osgi.util.tracker.ServiceTracker;
import org.osgi.util.tracker.ServiceTrackerCustomizer;
/**
* Uses OSGi services to discover JPA persistence providers
*
* Also acts as a resolver class (called by the Persistence class when resolving
* providers).
*/
public class Activator implements BundleActivator, PersistenceProviderResolver {
public static final String PERSISTENCE_PROVIDER = "javax.persistence.spi.PersistenceProvider";
private BundleContext ctx;
private ServiceTracker serviceTracker;
private Map<String, PersistenceProvider> providers = new Hashtable<String, PersistenceProvider>();
public void start(BundleContext context) throws Exception {
log(Level.FINE, context.getBundle().getSymbolicName() + " - starting...");
// Init the bundle context
this.ctx = context;
// Set up a tracker to add providers as they register themselves
ServiceTrackerCustomizer customizer = new ProviderTrackerCustomizer(this);
serviceTracker = new ServiceTracker(ctx, PERSISTENCE_PROVIDER, customizer);
serviceTracker.open();
// Set the persistence provider resolver to use OSGi services
PersistenceProviderResolverHolder.setPersistenceProviderResolver(this);
log(Level.FINE, context.getBundle().getSymbolicName() + " - started");
}
/**
* Obtain the provider from the reference and store it under it's name, if
* supplied or a generated name otherwise.
*/
PersistenceProvider addProvider(ServiceReference ref) {
PersistenceProvider provider = (PersistenceProvider) ctx.getService(ref);
String providerName = getProviderName(ref);
this.providers.put(providerName, provider);
return provider;
}
/**
* Remove the provider keyed by it's name.
*/
protected void removeProvider(ServiceReference ref) {
String providerName = getProviderName(ref);
this.providers.remove(providerName);
}
public void stop(BundleContext context) throws Exception {
log(Level.FINE, context.getBundle().getSymbolicName() + " - stopping...");
// Close the service tracker
this.serviceTracker.close();
this.serviceTracker = null;
// Clear the known provider list
// Note: the holder is in this bundle so it will no longer be available
// anyways. This is done to ensure all refs to providers in other
// bundles is removed
PersistenceProviderResolverHolder.setPersistenceProviderResolver(null);
this.providers.clear();
log(Level.FINE, context.getBundle().getSymbolicName() + " - stopped...");
}
/**
* Assumes that provider services are registered with property that
* indicates the name of the provider impl class.
*/
public String getProviderName(ServiceReference ref) {
String providerName = (String) ref.getProperty(PERSISTENCE_PROVIDER);
if (providerName == null) {
providerName = "PersistenceProvider-" + ref.hashCode();
}
return providerName;
}
protected Map<String, PersistenceProvider> getProviders() {
return this.providers;
}
/**
* Resolve/return existing providers (Implementation method for the
* ProviderResolver interface.)
*/
public List<PersistenceProvider> getPersistenceProviders() {
return new ArrayList<PersistenceProvider>(getProviders().values());
}
private static final String LOGGER_SUBSYSTEM = "org.eclipse.persistence.javax.persistence.osgi";
private Logger logger;
private void log(Level level, String message) {
if (this.logger == null) {
this.logger = Logger.getLogger(LOGGER_SUBSYSTEM);
}
this.logger.log(level, LOGGER_SUBSYSTEM + "::" + message);
}
/**
* Within OSGi where the providers are tracked dynamically the clear
* operation does nothing.
*/
public void clearCachedProviders() {
}
}