//$Id: EhCacheProvider.java 9964 2006-05-30 15:40:54Z epbernard $
/**
* Copyright 2003-2006 Greg Luck, Jboss Inc
*
* 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 org.hibernate.cache;
import java.util.Properties;
import java.net.URL;
import net.sf.ehcache.CacheManager;
import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;
import org.hibernate.cfg.Environment;
import org.hibernate.util.StringHelper;
import org.hibernate.util.ConfigHelper;
/**
* Cache Provider plugin for Hibernate
*
* Use <code>hibernate.cache.provider_class=org.hibernate.cache.EhCacheProvider</code>
* in Hibernate 3.x or later
*
* Taken from EhCache 0.9 distribution
* @author Greg Luck
* @author Emmanuel Bernard
*/
/**
* Cache Provider plugin for ehcache-1.2. New in this provider are ehcache support for multiple
* Hibernate session factories, each with its own ehcache configuration, and non Serializable keys and values.
* Ehcache-1.2 also has many other features such as cluster support and listeners, which can be used seamlessly simply
* by configurion in ehcache.xml.
* <p/>
* Use <code>hibernate.cache.provider_class=org.hibernate.cache.EhCacheProvider</code> in the Hibernate configuration
* to enable this provider for Hibernate's second level cache.
* <p/>
* When configuring multiple ehcache CacheManagers, as you would where you have multiple Hibernate Configurations and
* multiple SessionFactories, specify in each Hibernate configuration the ehcache configuration using
* the property <code>hibernate.cache.provider_configuration_file_resource_path</code> An example to set an ehcache configuration
* called ehcache-2.xml would be <code>hibernate.cache.provider_configuration_file_resource_path=/ehcache-2.xml</code>. If the leading
* slash is not there one will be added. The configuration file will be looked for in the root of the classpath.
* <p/>
* Updated for ehcache-1.2. Note this provider requires ehcache-1.2.jar. Make sure ehcache-1.1.jar or earlier
* is not in the classpath or it will not work.
* <p/>
* See http://ehcache.sf.net for documentation on ehcache
* <p/>
*
* @author Greg Luck
* @author Emmanuel Bernard
*/
public class EhCacheProvider implements CacheProvider {
private static final Log log = LogFactory.getLog(EhCacheProvider.class);
private CacheManager manager;
/**
* Builds a Cache.
* <p>
* Even though this method provides properties, they are not used.
* Properties for EHCache are specified in the ehcache.xml file.
* Configuration will be read from ehcache.xml for a cache declaration
* where the name attribute matches the name parameter in this builder.
*
* @param name the name of the cache. Must match a cache configured in ehcache.xml
* @param properties not used
* @return a newly built cache will be built and initialised
* @throws CacheException inter alia, if a cache of the same name already exists
*/
public Cache buildCache(String name, Properties properties) throws CacheException {
try {
net.sf.ehcache.Cache cache = manager.getCache(name);
if (cache == null) {
log.warn("Could not find configuration [" + name + "]; using defaults.");
manager.addCache(name);
cache = manager.getCache(name);
log.debug("started EHCache region: " + name);
}
return new EhCache(cache);
}
catch (net.sf.ehcache.CacheException e) {
throw new CacheException(e);
}
}
/**
* Returns the next timestamp.
*/
public long nextTimestamp() {
return Timestamper.next();
}
/**
* Callback to perform any necessary initialization of the underlying cache implementation
* during SessionFactory construction.
*
* @param properties current configuration settings.
*/
public void start(Properties properties) throws CacheException {
if (manager != null) {
log.warn("Attempt to restart an already started EhCacheProvider. Use sessionFactory.close() " +
" between repeated calls to buildSessionFactory. Using previously created EhCacheProvider." +
" If this behaviour is required, consider using net.sf.ehcache.hibernate.SingletonEhCacheProvider.");
return;
}
try {
String configurationResourceName = null;
if (properties != null) {
configurationResourceName = (String) properties.get( Environment.CACHE_PROVIDER_CONFIG );
}
if ( StringHelper.isEmpty( configurationResourceName ) ) {
manager = new CacheManager();
} else {
URL url = loadResource(configurationResourceName);
manager = new CacheManager(url);
}
} catch (net.sf.ehcache.CacheException e) {
//yukky! Don't you have subclasses for that!
//TODO race conditions can happen here
if (e.getMessage().startsWith("Cannot parseConfiguration CacheManager. Attempt to create a new instance of " +
"CacheManager using the diskStorePath")) {
throw new CacheException("Attempt to restart an already started EhCacheProvider. Use sessionFactory.close() " +
" between repeated calls to buildSessionFactory. Consider using net.sf.ehcache.hibernate.SingletonEhCacheProvider."
, e );
} else {
throw e;
}
}
}
private URL loadResource(String configurationResourceName) {
URL url = ConfigHelper.locateConfig( configurationResourceName );
if (log.isDebugEnabled()) {
log.debug("Creating EhCacheProvider from a specified resource: "
+ configurationResourceName + " Resolved to URL: " + url);
}
return url;
}
/**
* Callback to perform any necessary cleanup of the underlying cache implementation
* during SessionFactory.close().
*/
public void stop() {
if (manager != null) {
manager.shutdown();
manager = null;
}
}
public boolean isMinimalPutsEnabledByDefault() {
return false;
}
}
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