defaultwebcontroller.java

sun公司的petstore,一个J2ee的示例应用程序.

/*
 * Copyright 2002 Sun Microsystems, Inc. All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 *
 * - Redistributions of source code must retain the above copyright
 *   notice, this list of conditions and the following disclaimer.
 *
 * - Redistribution in binary form must reproduce the above copyright
 *   notice, this list of conditions and the following disclaimer in
 *   the documentation and/or other materials provided with the
 *   distribution.
 *
 * Neither the name of Sun Microsystems, Inc. or the names of
 * contributors may be used to endorse or promote products derived
 * from this software without specific prior written permission.
 *
 * This software is provided "AS IS," without a warranty of any
 * kind. ALL EXPRESS OR IMPLIED CONDITIONS, REPRESENTATIONS AND
 * WARRANTIES, INCLUDING ANY IMPLIED WARRANTY OF MERCHANTABILITY,
 * FITNESS FOR A PARTICULAR PURPOSE OR NON-INFRINGEMENT, ARE HEREBY
 * EXCLUDED. SUN AND ITS LICENSORS SHALL NOT BE LIABLE FOR ANY DAMAGES
 * SUFFERED BY LICENSEE AS A RESULT OF USING, MODIFYING OR
 * DISTRIBUTING THE SOFTWARE OR ITS DERIVATIVES. IN NO EVENT WILL SUN
 * OR ITS LICENSORS BE LIABLE FOR ANY LOST REVENUE, PROFIT OR DATA, OR
 * FOR DIRECT, INDIRECT, SPECIAL, CONSEQUENTIAL, INCIDENTAL OR
 * PUNITIVE DAMAGES, HOWEVER CAUSED AND REGARDLESS OF THE THEORY OF
 * LIABILITY, ARISING OUT OF THE USE OF OR INABILITY TO USE SOFTWARE,
 * EVEN IF SUN HAS BEEN ADVISED OF THE POSSIBILITY OF SUCH DAMAGES.
 *
 * You acknowledge that Software is not designed, licensed or intended
 * for use in the design, construction, operation or maintenance of
 * any nuclear facility.
 */
package com.sun.j2ee.blueprints.waf.controller.web;

import java.util.Locale;
import java.util.Collection;

// J2EE imports
import javax.servlet.http.HttpSession;
import javax.servlet.ServletContext;
import javax.ejb.RemoveException;

// WAF imports
import com.sun.j2ee.blueprints.util.tracer.Debug;
import com.sun.j2ee.blueprints.waf.util.JNDINames;
import com.sun.j2ee.blueprints.waf.controller.web.util.WebKeys;
import com.sun.j2ee.blueprints.waf.event.Event;
import com.sun.j2ee.blueprints.waf.event.EventResponse;
import com.sun.j2ee.blueprints.waf.controller.ejb.EJBControllerLocal;

import com.sun.j2ee.blueprints.waf.exceptions.GeneralFailureException;
import com.sun.j2ee.blueprints.waf.event.EventException;
import com.sun.j2ee.blueprints.waf.exceptions.AppException;

/**
 * This class is essentially just a proxy object that calls methods on the
 * EJB tier using the com.sun.j2ee.blueprints.waf.controller.ejb.ShoppingClientControllerEJB
 * object. All the methods that access the EJB are synchronized so
 * that concurrent requests do not happen to the stateful session bean.
 *
 */
public class DefaultWebController implements WebController {

    public DefaultWebController() {
    }

    /**
     * constructor for an HTTP client.
     * @param the ServletContext  object of the application
     */
    public void init(ServletContext context) {
           context.setAttribute(WebKeys.WEB_CONTROLLER, this);
    }

    /**
     * feeds the specified event to the state machine of the business logic.
     *
     * @param ese is the current event
     * @return a com.sun.j2ee.blueprints.waf.event.EventResponse object which can be extend to carry any payload.
     * @exception com.sun.j2ee.blueprints.waf.event.EventException <description>
     * @exception com.sun.j2ee.blueprints.waf.exceptions.GeneralFailureException
     */
    public synchronized EventResponse handleEvent(Event ev, HttpSession session)
        throws EventException {
            DefaultComponentManager cm = (DefaultComponentManager)session.getAttribute(WebKeys.COMPONENT_MANAGER);
            EJBControllerLocal controllerEJB =cm.getEJBController(session);
            return controllerEJB.processEvent(ev);
    }

     /**
     * frees up all the resources associated with this controller and
     * destroys itself.
     */
    public synchronized void destroy(HttpSession session) {
        // call ejb remove on EJBClientController
        DefaultComponentManager cm = (DefaultComponentManager)session.getAttribute(WebKeys.COMPONENT_MANAGER);
        EJBControllerLocal controllerEJB =cm.getEJBController(session);
        try {
            controllerEJB.remove();
        } catch(RemoveException re){
            // ignore, after all its only a remove() call!
            Debug.print(re);
        }
    }
}