/*
* org.openmicroscopy.shoola.env.cache.CacheServiceFactory
*
*------------------------------------------------------------------------------
* Copyright (C) 2006-2008 University of Dundee. All rights reserved.
*
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; either version 2 of the License, or
* (at your option) any later version.
* 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 General Public License for more details.
*
* You should have received a copy of the GNU General Public License along
* with this program; if not, write to the Free Software Foundation, Inc.,
* 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
*
*------------------------------------------------------------------------------
*/
package org.openmicroscopy.shoola.env.cache;
//Java imports
import java.io.InputStream;
//Third-party libraries
//Application-internal dependencies
import org.openmicroscopy.shoola.env.Container;
import org.openmicroscopy.shoola.env.LookupNames;
import org.openmicroscopy.shoola.env.config.Registry;
import org.openmicroscopy.shoola.util.file.IOUtil;
import omero.gateway.cache.CacheService;
/**
* A factory for the {@link CacheService}.
*
* @author Jean-Marie Burel
* <a href="mailto:j.burel@dundee.ac.uk">j.burel@dundee.ac.uk</a>
* @author Donald MacDonald
* <a href="mailto:donald@lifesci.dundee.ac.uk">donald@lifesci.dundee.ac.uk</a>
* @version 3.0
* <small>
* (<b>Internal version:</b> $Revision: $Date: $)
* </small>
* @since 3.0-Beta3
*/
public class CacheServiceFactory
{
/** The name of the cache configuration file in the config directory. */
public static final String CACHE_CONFIG_FILE = "ehcache.xml";
/**
* Creates a new {@link CacheService}.
*
* @param container Reference to the container.
* @return See above.
*/
public static CacheService makeNew(Container container)
{
//NB: this can't be called outside of container b/c agents have no refs
//to the singleton container. So we can be sure this method is going to
//create services just once.
if (container == null) return null;
//If caching is off, then we return the no-op adapter.
Registry reg = container.getRegistry();
Boolean isCachingOn = (Boolean) reg.lookup(LookupNames.CACHE_ON);
if (!isCachingOn.booleanValue()) return makeNoOpCache();
//Ok we have to cache, so try and read the config file.
InputStream config = loadConfig(
container.getConfigFileRelative(CACHE_CONFIG_FILE));
if (config == null) return makeNoOpCache();
//We have a config file, set up ehcache.
CacheService cache = new CacheServiceImpl(config,
container.getRegistry().getLogger());
try {
config.close();
} catch (Exception e) {}
return cache;
}
/**
* Shuts downs the caching service.
*
* @param container Reference to the container.
*/
public static void shutdown(Container container)
{
//NB: this can't be called outside of container b/c agents have no refs
//to the singleton container. So we can be sure this method is going to
//create services just once.
if (container == null) return;
Registry reg = container.getRegistry();
((CacheServiceImpl) reg.getCacheService()).shutDown();
}
/**
* Creates a no-operation implementation of {@link CacheService}.
*
* @return See above.
*/
private static CacheService makeNoOpCache()
{
return new CacheService() {
public void addElement(int cacheID, Object key, Object element) {}
public int createCache() { return -1; }
public int createCache(int type) { return -1; }
public int createCache(int type, int size) { return -1; }
public Object getElement(int cacheID, Object key) { return null; }
public void removeCache(int cacheID) {}
public void clearCache(int cacheID) {}
public void setCacheEntries(int cacheID, int size) {}
public void clearAllCaches() {}
public void shutDown() {}
};
}
/**
* Reads in the specified file as a property object.
*
* @param file Absolute pathname to the file.
* @return The content of the file as a property object or
* <code>null</code> if an error occurred.
*/
private static InputStream loadConfig(String file)
{
InputStream stream;
try {
stream = IOUtil.readConfigFile(file);
} catch (Exception e) {
return null;
}
return stream;
}
}