HHH-3450 : SingletonEhCacheProvider

git-svn-id: https://svn.jboss.org/repos/hibernate/core/branches/Branch_3_3@15186 1b8cb986-b30d-0410-93ca-fae66ebed9b2

cache-ehcache/src/main/java/org/hibernate/cache/EhCache.java

@@ -49,7 +49,7 @@ public class EhCache implements Cache {
 
 	private static final int SIXTY_THOUSAND_MS = 60000;
 
-	private net.sf.ehcache.Cache cache;
+	private net.sf.ehcache.Ehcache cache;
 
 	/**
 	 * Creates a new Hibernate pluggable cache based on a cache name.
@@ -57,7 +57,7 @@ public class EhCache implements Cache {
 	 *
 	 * @param cache The underlying EhCache instance to use.
 	 */
-	public EhCache(net.sf.ehcache.Cache cache) {
+	public EhCache(net.sf.ehcache.Ehcache cache) {
 		this.cache = cache;
 	}
 
@@ -278,4 +278,4 @@ public class EhCache implements Cache {
 		return "EHCache(" + getRegionName() + ')';
 	}
 
-}
+}

cache-ehcache/src/main/java/org/hibernate/cache/SingletonEhCacheProvider.java

@@ -0,0 +1,202 @@
+/*
+ * Hibernate, Relational Persistence for Idiomatic Java
+ *
+ * Copyright (c) 2008, Red Hat Middleware LLC or third-party contributors as
+ * indicated by the @author tags or express copyright attribution
+ * statements applied by the authors.  All third-party contributions are
+ * distributed under license by Red Hat Middleware LLC.
+ *
+ * This copyrighted material is made available to anyone wishing to use, modify,
+ * copy, or redistribute it subject to the terms and conditions of the GNU
+ * Lesser General Public License, as published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
+ * or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU Lesser General Public License
+ * for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public License
+ * along with this distribution; if not, write to:
+ * Free Software Foundation, Inc.
+ * 51 Franklin Street, Fifth Floor
+ * Boston, MA  02110-1301  USA
+ *
+ */
+package org.hibernate.cache;
+
+import net.sf.ehcache.CacheManager;
+import net.sf.ehcache.util.ClassLoaderUtil;
+
+import java.net.URL;
+import java.util.Properties;
+import java.util.logging.Logger;
+import java.util.logging.Level;
+
+/**
+ * Singleton cache Provider plugin for Hibernate 3.2 and ehcache-1.2. New in this provider is support for
+ * non Serializable keys and values. This provider works as a Singleton. No matter how many Hibernate Configurations
+ * you have, only one ehcache CacheManager is used. See EhCacheProvider for a non-singleton implementation.
+ * <p/>
+ * 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=net.sf.ehcache.hibernate.SingletonEhCacheProvider</code> in the Hibernate configuration
+ * to enable this provider for Hibernate's second level cache.
+ * <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
+ * @version $Id: SingletonEhCacheProvider.java 744 2008-08-16 20:10:49Z gregluck $
+ */
+public final class SingletonEhCacheProvider implements CacheProvider {
+
+	/**
+	 * The Hibernate system property specifying the location of the ehcache configuration file name.
+	 * <p/
+	 * If not set, ehcache.xml will be looked for in the root of the classpath.
+	 * <p/>
+	 * If set to say ehcache-1.xml, ehcache-1.xml will be looked for in the root of the classpath.
+	 */
+	public static final String NET_SF_EHCACHE_CONFIGURATION_RESOURCE_NAME = "net.sf.ehcache.configurationResourceName";
+
+	private static final Logger LOG = Logger.getLogger( SingletonEhCacheProvider.class.getName() );
+
+	/**
+	 * To be backwardly compatible with a lot of Hibernate code out there, allow multiple starts and stops on the
+	 * one singleton CacheManager. Keep a count of references to only stop on when only one reference is held.
+	 */
+	private static int referenceCount;
+
+	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 org.hibernate.cache.CacheException
+	 *          inter alia, if a cache of the same name already exists
+	 */
+	public final Cache buildCache(String name, Properties properties) throws CacheException {
+		try {
+			net.sf.ehcache.Ehcache cache = manager.getEhcache( name );
+			if ( cache == null ) {
+				SingletonEhCacheProvider.LOG.warning(
+						"Could not find a specific ehcache configuration for cache named ["
+								+ name + "]; using defaults."
+				);
+				manager.addCache( name );
+				cache = manager.getEhcache( name );
+				SingletonEhCacheProvider.LOG.fine( "started EHCache region: " + name );
+			}
+			return new EhCache( cache );
+		}
+		catch ( net.sf.ehcache.CacheException e ) {
+			throw new CacheException( e );
+		}
+	}
+
+	/**
+	 * Returns the next timestamp.
+	 */
+	public final long nextTimestamp() {
+		return Timestamper.next();
+	}
+
+	/**
+	 * Callback to perform any necessary initialization of the underlying cache implementation
+	 * during SessionFactory construction.
+	 * <p/>
+	 *
+	 * @param properties current configuration settings.
+	 */
+	public final void start(Properties properties) throws CacheException {
+		String configurationResourceName = null;
+		if ( properties != null ) {
+			configurationResourceName = ( String ) properties.get( NET_SF_EHCACHE_CONFIGURATION_RESOURCE_NAME );
+		}
+		if ( configurationResourceName == null || configurationResourceName.length() == 0 ) {
+			manager = CacheManager.create();
+			referenceCount++;
+		}
+		else {
+			if ( !configurationResourceName.startsWith( "/" ) ) {
+				configurationResourceName = "/" + configurationResourceName;
+				if ( LOG.isLoggable( Level.FINE ) ) {
+					LOG.fine(
+							"prepending / to " + configurationResourceName + ". It should be placed in the root"
+									+ "of the classpath rather than in a package."
+					);
+				}
+			}
+			URL url = loadResource( configurationResourceName );
+			manager = CacheManager.create( url );
+			referenceCount++;
+		}
+	}
+
+	private URL loadResource(String configurationResourceName) {
+		ClassLoader standardClassloader = ClassLoaderUtil.getStandardClassLoader();
+		URL url = null;
+		if ( standardClassloader != null ) {
+			url = standardClassloader.getResource( configurationResourceName );
+		}
+		if ( url == null ) {
+			url = this.getClass().getResource( configurationResourceName );
+		}
+		if ( LOG.isLoggable( Level.FINE ) ) {
+			LOG.fine(
+					"Creating EhCacheProvider from a specified resource: "
+							+ configurationResourceName + " Resolved to URL: " + url
+			);
+		}
+		if ( url == null ) {
+			if ( LOG.isLoggable( Level.WARNING ) ) {
+				LOG.warning(
+						"A configurationResourceName was set to " + configurationResourceName +
+								" but the resource could not be loaded from the classpath." +
+								"Ehcache will configure itself using defaults."
+				);
+			}
+		}
+		return url;
+	}
+
+	/**
+	 * Callback to perform any necessary cleanup of the underlying cache implementation
+	 * during SessionFactory.close().
+	 */
+	public void stop() {
+		if ( manager != null ) {
+			referenceCount--;
+			if ( referenceCount == 0 ) {
+				manager.shutdown();
+			}
+			manager = null;
+		}
+	}
+
+	/**
+	 * Not sure what this is supposed to do.
+	 *
+	 * @return false to be safe
+	 */
+	public final boolean isMinimalPutsEnabledByDefault() {
+		return false;
+	}
+
+}