CachingServiceLocator.java

/*
 *  Copyright (c) 2008 Boulder Community Foundation - iVolunteer
 *
 *  Permission is hereby granted, free of charge, to any person obtaining a copy
 *  of this software and associated documentation files (the "Software"), to deal
 *  in the Software without restriction, including without limitation the rights
 *  to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
 *  copies of the Software, and to permit persons to whom the Software is
 *  furnished to do so, subject to the following conditions:
 *
 *  The above copyright notice and this permission notice shall be included in
 *  all copies or substantial portions of the Software.
 *
 *  THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
 *  IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
 *  FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
 *  AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
 *  LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
 *  OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
 *  THE SOFTWARE.
 */

package core;

import java.util.HashMap;
import java.util.Map;
import java.util.Collections;
import java.net.URL;

import javax.ejb.EJBHome;
import javax.ejb.Local;
import javax.jms.ConnectionFactory;
import javax.jms.Destination;
import javax.naming.InitialContext;
import javax.naming.NamingException;
import javax.rmi.PortableRemoteObject;
import javax.sql.DataSource;
import javax.mail.Session;

/**
 * 
 * @author Dave Angulo
 */
public class CachingServiceLocator {

	private InitialContext					ic;
	private Map<String, Object>				cache;

	private static CachingServiceLocator	me;

	static {
		try {
			me = new CachingServiceLocator();
		} catch (NamingException se) {
			throw new RuntimeException(se);
		}
	}

	private CachingServiceLocator() throws NamingException {
		ic = new InitialContext();
		cache = Collections.synchronizedMap(new HashMap<String, Object>());
	}

	public static CachingServiceLocator getInstance() {
		return me;
	}

	private Object lookup(String jndiName) throws NamingException {
		Object cachedObj = cache.get(jndiName);
		if (cachedObj == null) {
			cachedObj = ic.lookup(jndiName);
			cache.put(jndiName, cachedObj);
		}
		return cachedObj;
	}

	/**
	 * Returns the ejb Local home factory. If this ejb home factory has already
	 * been clients need to cast to the type of EJBHome they desire
	 * 
	 * @return the EJB Home corresponding to the homeName
	 */
	public Object getLocalHome(String jndiHomeName) throws NamingException {
		return lookup(jndiHomeName);
	}

	/**
	 * Returns the ejb Remote home factory. If this ejb home factory has already
	 * been clients need to cast to the type of EJBHome they desire
	 * 
	 * @return the EJB Home corresponding to the homeName
	 */
	public EJBHome getRemoteHome(String jndiHomeName, Class className) throws NamingException {
		Object objref = lookup(jndiHomeName);
		return (EJBHome) PortableRemoteObject.narrow(objref, className);
	}

	/**
	 * This method helps in obtaining the topic factory
	 * 
	 * @return the factory for the factory to get topic connections from
	 */
	public ConnectionFactory getConnectionFactory(String connFactoryName) throws NamingException {
		return (ConnectionFactory) lookup(connFactoryName);
	}

	/**
	 * This method obtains the topc itself for a caller
	 * 
	 * @return the Topic Destination to send messages to
	 */
	public Destination getDestination(String destName) throws NamingException {
		return (Destination) lookup(destName);
	}

	/**
	 * This method obtains the datasource
	 * 
	 * @return the DataSource corresponding to the name parameter
	 */
	public DataSource getDataSource(String dataSourceName) throws NamingException {
		return (DataSource) lookup(dataSourceName);
	}

	/**
	 * This method obtains the mail session
	 * 
	 * @return the Session corresponding to the name parameter
	 */
	public Session getSession(String sessionName) throws NamingException {
		return (Session) lookup(sessionName);
	}

	/**
	 * This method obtains the URL
	 * 
	 * @return the URL value corresponding to the env entry name.
	 */
	public URL getUrl(String envName) throws NamingException {
		return (URL) lookup(envName);
	}

	/**
	 * This method obtains the boolean
	 * 
	 * @return the boolean value corresponding to the env entry such as
	 *         SEND_CONFIRMATION_MAIL property.
	 */
	public boolean getBoolean(String envName) throws NamingException {
		Boolean bool = (Boolean) lookup(envName);
		return bool.booleanValue();
	}

	/**
	 * This method obtains the String
	 * 
	 * @return the String value corresponding to the env entry name.
	 */
	public String getString(String envName) throws NamingException {
		return (String) lookup(envName);
	}
}