newcustomerreceiverbean.java

J2EE开发与Weblogic一书中的源代码

package com.learnweblogic.examples.ch10.customer;

import java.rmi.RemoteException;

import javax.ejb.EJBException;
import javax.ejb.MessageDrivenBean;
import javax.ejb.MessageDrivenContext;
import javax.jms.JMSException;
import javax.jms.MapMessage;
import javax.jms.Message;
import javax.jms.MessageListener;
import javax.naming.Context;
import javax.naming.InitialContext;
import javax.rmi.PortableRemoteObject;

public class NewCustomerReceiverBean
    implements MessageDrivenBean, MessageListener {

    private static final int BAD_MESSAGE_TYPE = 1;
    private static final int CUSTOMER_ALREADY_EXISTS = 2;

    private MessageDrivenContext ctx;

    private NewCustomer newCustomer;

    public void setMessageDrivenContext(MessageDrivenContext c) {
        ctx = c;
        try {
            Context ic = new InitialContext();
            Object h = ic.lookup("java:/comp/env/ejb/NewCustomerHome");

            NewCustomerHome home =
                (NewCustomerHome) PortableRemoteObject.narrow(
                    h,
                    NewCustomerHome.class);

            newCustomer = home.create();
        } catch (Exception e) {
            e.printStackTrace();
            throw new EJBException(e);
        }
    }

    public void ejbCreate() {
    }

    public void ejbRemove() {
    }

    private void publishError(int errorType, Throwable th) {
        // This method handles application errors in the incoming
        // messages. One common design published to an error topic here.
        // For simplicity, we only print an error message and continue
        switch (errorType) {

            case BAD_MESSAGE_TYPE :
                System.err.println("Bad Message Type received: " + th);
                break;

            case CUSTOMER_ALREADY_EXISTS :
                System.err.println("Customer already exists: " + th);
                break;

            default :
                throw new EJBException("Unexpected error type: " + errorType);
        }
    }

    public void onMessage(Message m) {
        MapMessage msg = (MapMessage) m;

        try {
            int id = msg.getInt("ID");
            String firstName = msg.getString("FIRST_NAME");
            String lastName = msg.getString("LAST_NAME");
            String emailAddress = msg.getString("EMAIL_ADDRESS");
            newCustomer.enterNewCustomer(id, firstName, lastName, emailAddress);

        } catch (JMSException e) {
            // message was mal-formed
            publishError(BAD_MESSAGE_TYPE, e);
        } catch (InvalidCustomerException ice) {
            // customer id already existsed
            publishError(CUSTOMER_ALREADY_EXISTS, ice);
        } catch (RemoteException re) {
            re.printStackTrace();
            ctx.setRollbackOnly();
        }
    }
}