import java.util.Hashtable;

import javax.naming.Context;
import javax.naming.Name;
import javax.naming.RefAddr;
import javax.naming.Reference;
import javax.naming.event.EventContext;
import javax.naming.event.NamespaceChangeListener;
import javax.naming.event.NamingEvent;
import javax.naming.event.NamingExceptionEvent;
import javax.naming.spi.ObjectFactory;

import net.sf.ehcache.CacheManager;

public class CacheManagerFactory implements ObjectFactory {

    private static final String CONFIGURATION_FILE = "configurationFile";

    private static final NamespaceChangeListener SHUTDOWN_LISTENER = new NamespaceChangeListener() {

        @Override
        public void namingExceptionThrown(NamingExceptionEvent event) {}

        @Override
        public void objectAdded(NamingEvent event) {}

        @Override
        public void objectRemoved(NamingEvent event) {
            Object object = event.getOldBinding().getObject();
            if (object instanceof CacheManager) {
                CacheManager cacheManager = (CacheManager) object;
                cacheManager.shutdown();
            }
        }

        @Override
        public void objectRenamed(NamingEvent event) {}
    };

    @Override
    public CacheManager getObjectInstance(Object object, Name jndiName, Context context, Hashtable<?, ?> environment) throws Exception {
        String configurationFile = null;
        if (object instanceof Reference) {
            Reference reference = (Reference) object;
            RefAddr refAddr = reference.get(CONFIGURATION_FILE);
            if (refAddr != null) {
                configurationFile = (String) refAddr.getContent();
            }
        }
        if (context instanceof EventContext) {
            EventContext eventContext = (EventContext) context;
            eventContext.addNamingListener(jndiName, EventContext.OBJECT_SCOPE, SHUTDOWN_LISTENER);
        }
        return configurationFile == null ? CacheManager.newInstance() : CacheManager.newInstance(configurationFile);
    }
}