exchangebean.java

Oracle的J2EE Sample

/*
 * @author  : Elangovan
 * @version : 1.0
 *
 * Development Environment : Oracle9i JDeveloper
 * Name of the File        : ExchangeBean.java
 *
 * Creation / Modification History
 *    Elangovan           26-Apr-2002        Created
 *
 */
package oracle.otnsamples.ibfbs.admin.ejb;

import javax.ejb.SessionBean;
import javax.ejb.SessionContext;
import javax.naming.InitialContext;
import javax.naming.Context;
import java.util.Date;

/**
 * This class implements the Exchange interface. This bean stimulates a Stock
 * Exchange, it executes all orders it receives and sends an conformation email.
 * To enable asynchronous processing, all orders are queued in the ExchangeQueue
 * and then processed by Exchange Service.
 * 
 * @see ExchangeQueue.java
 *
 */
public class ExchangeBean implements SessionBean {

  // Handle to MailService Home 
  private MailServiceHome mailServiceHome = null;

  /**
   * Standard callback method, invoked by Container when this Session Bean
   * is created. Initializes MailService.
   */
  public void ejbCreate() {
    try {

      // Lookup for mailservice
      Context ctx = new InitialContext();

      mailServiceHome = (MailServiceHome) ctx.lookup("MailService");
          
    } catch(Exception ex) {
      System.err.println("ExchangeBean.ejbCreate: Could not initialize Mail Service :"+
                          ex.toString());
    }
  }

  /**
   * Executes the trade order and sends a confirmation mail.
   *
   * @param toAddress To mail address where confirmation has to be sent
   * @param symbol stock symbol traded
   * @param tradeDate trade date
   * @param tradeType Trade type, S - sell, B - buy, T - transfer
   * @param qty quantity of stocks traded
   * @return status of process order, 0 - success, -1 - failure
   * @since 1.0
   */
  public Integer processOrder(String toAddress, String symbol, Date tradeDate,
                              String tradeType, Integer qty) {

    // Its assumed that sending a mail sucessfully completes the order processing
    
    // Status of the processed order
    Integer executed = new Integer(-1);
    try {
        
        // Update Order Status in Trade Details
        // ..........
        
        // Send the confirmation mail
        MailService     mailService     = mailServiceHome.create();
        
        executed = mailService.sendMail(toAddress, "[e-mail]",
                                        " Stock Order executed ",
                                        getMsg(symbol, tradeDate, tradeType,
                                               qty));

    } catch (Exception ex) {  // Failure

      System.err.println("ExchangeBean.processOrder: Error processing Order :" + ex.toString());

    }

    return executed;
  }

  /**
   * Constructs a HTML message for order confirmation.
   *
   * @param symbol stock symbol
   * @param tradeDate trade date
   * @param tradeType trade type , 'S' - sell , 'B' - buy
   * @param qty Quantity traded
   * @return mail body in HTML format
   * @since 1.0
   */
  private String getMsg(String symbol, Date tradeDate, String tType,
                        Integer qty) {

    StringBuffer sb        = new StringBuffer();
    String       tradeType = null;
    if (tType.equals("T")) {
      tradeType = " Transfer ";
    } else if (tType.equals("B")) {
      tradeType = " Buy ";
    } else if (tType.equals("S")) {
      tradeType = " Sell ";
    }

    sb.append("<br><br>")
      .append(" Hi, <br><br>")
      .append("<br><h4><u>Trade Order Details</u></h4>")
      .append("<table border='1'>")
      .append(" <tr><td> Symbol</td><td>" + symbol + "</td></tr>")
      .append(" <tr><td> Type</td><td>" + tradeType + "</td></tr>")
      .append(" <tr><td> Date</td><td>" + tradeDate + "</td></tr>")
      .append(" <tr><td> Quantity</td><td>" + qty.intValue() + "</td></tr>")
      .append("</table><br>")
      .append("<font color='#008000'><b>Your order has been executed ")
      .append("successfully.</b></font><br>")
      .append("<br><br>")
      .append("Thank you for trading with us.")
      .append("<br><br>Happy Trading !! <br> FBS Team.");

    return sb.toString();
  }


  // Standard call back methods

  public void ejbActivate() {}

  public void ejbPassivate() {}

  public void ejbRemove() {}

  public void setSessionContext(SessionContext ctx) {}
}