package ejava.examples.asyncmarket.web;
   
   import java.util.Enumeration;
   import java.util.Properties;
   
   import javax.naming.Context;
   import javax.naming.InitialContext;
   import javax.naming.NamingException;
   import javax.servlet.ServletContext;
  
  import org.apache.commons.logging.Log;
  import org.apache.commons.logging.LogFactory;
  
  import ejava.examples.asyncmarket.AuctionMgmt;
  import ejava.examples.asyncmarket.Buyer;
  import ejava.examples.asyncmarket.Seller;
  import ejava.examples.asyncmarket.UserMgmt;
  import ejava.examples.asyncmarket.ejb.AuctionMgmtLocal;
  import ejava.examples.asyncmarket.ejb.AuctionMgmtRemote;
  import ejava.examples.asyncmarket.ejb.BuyerLocal;
  import ejava.examples.asyncmarket.ejb.BuyerRemote;
  import ejava.examples.asyncmarket.ejb.SellerLocal;
  import ejava.examples.asyncmarket.ejb.SellerRemote;
  import ejava.examples.asyncmarket.ejb.UserMgmtLocal;
  import ejava.examples.asyncmarket.ejb.UserMgmtRemote;
  import ejava.util.ejb.EJBClient;
  
  /**
   * This is a helper class used to help locate EJBs when running in a 
   * remote web container -- such as Jetty.
   *  
   * TODO: factor out JNDI properties into a jndi.properties file
   */
  public class JNDIHelper {
      private static final Log log = LogFactory.getLog(JNDIHelper.class);
      public static final String AUCTION_MGMT_REMOTE_JNDI=
      	EJBClient.getRemoteLookupName("asyncMarketEAR", "asyncMarketEJB", 
  			"AuctionMgmtEJB", AuctionMgmtRemote.class.getName());    
  	public static final String USER_MGMT_REMOTE_JNDI =
  		EJBClient.getRemoteLookupName("asyncMarketEAR", "asyncMarketEJB", 
  			"UserMgmtEJB", UserMgmtRemote.class.getName());
  	public static final String SELLER_REMOTE_JNDI = 
  		EJBClient.getRemoteLookupName("asyncMarketEAR", "asyncMarketEJB", 
  			"SellerEJB", SellerRemote.class.getName());	
  	public static final String BUYER_REMOTE_JNDI = 
  		EJBClient.getRemoteLookupName("asyncMarketEAR", "asyncMarketEJB", 
  			"BuyerEJB", BuyerRemote.class.getName());
  
      private Context jndi;
      
      public JNDIHelper(ServletContext context) throws NamingException {
      	jndi=getInitialContext(context);
      }
      public void close() {
      	try {
      		jndi.close();
      	} catch (NamingException ex) {
      		throw new RuntimeException("unexpected error during JNDI.close()", ex);
      	}
      }
      
      public AuctionMgmt getAuctionMgmt() throws NamingException {
      	return lookup(AuctionMgmt.class, jndi, AUCTION_MGMT_REMOTE_JNDI);
      }
      
      public UserMgmt getUserMgmt() throws NamingException {
      	return lookup(UserMgmt.class, jndi, USER_MGMT_REMOTE_JNDI);
      }
  
      public Seller getSeller() throws NamingException {
      	return lookup(Seller.class, jndi, SELLER_REMOTE_JNDI);
      }
      
      public Buyer getBuyer() throws NamingException {
      	return lookup(Buyer.class, jndi, BUYER_REMOTE_JNDI);
      }
  
      
      private Context getInitialContext(ServletContext context) 
          throws NamingException {
          
          //build an InitialContext from Servlet.init properties in web.xml
          Properties jndiProperties = new Properties();
          for(Enumeration<?> e=context.getInitParameterNames();
              e.hasMoreElements(); ) {
              String key = (String)e.nextElement();
              String value=(String)context.getInitParameter(key);
              if (key.startsWith("java.naming")) {
                  jndiProperties.put(key, value);
              }                    
          }
          log.debug("jndiProperties=" + jndiProperties);
          InitialContext jndi = new InitialContext(jndiProperties);
          log.debug("jndi=" + jndiProperties);
          return jndi;
      }
  
      @SuppressWarnings("unchecked")
  	private <T> T lookup(Class<T> lazz, Context jndi, String remoteJNDI) 
     		throws NamingException { 
         T object = null;            
         object = (T)jndi.lookup(remoteJNDI);
         log.debug("object=" + object);
         return object;
     }
 }