statemachine.java

Sun的宠物店源码

/*
 * 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
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 * 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.ejb;

import java.rmi.RemoteException;
import javax.naming.InitialContext;
import javax.naming.NamingException;
import javax.ejb.SessionContext;

import java.util.Collection;
import java.util.HashMap;

// waf imports
import com.sun.j2ee.blueprints.waf.controller.ejb.action.EJBAction;
import com.sun.j2ee.blueprints.util.tracer.Debug;
import com.sun.j2ee.blueprints.waf.event.EventException;
import com.sun.j2ee.blueprints.waf.event.EventResponse;
import com.sun.j2ee.blueprints.waf.event.Event;

/**
 * This class is a responsible for processing Events recieved from the
 * client tier. Af part of the WAF framework the events are generated
 * by web actions.
 *
 * The State Machine ties all EJB components together dynamically at
 * runtime thus providing support for reusable components.
 *
 * This class should not be updated to handle various event types.
 * This class will use ActionHandlers to handle events that require
 * processing beyond the scope of this class.
 *
 * The mapping of the event names to handlers is mangaged by the JNDI
 * key contained in the Event:getEventName() which is looked up from
 * an environment entry located in the EJB Deployment descriptor of the
 * EJBClientController. A second option to event handling is to do so
 * in the XML file.
 *
 * State may be stored in the attributeMap
 *
 *
 */
public class StateMachine implements java.io.Serializable {

    private EJBControllerLocalEJB ccejb;
    private HashMap attributeMap;
    private HashMap actionMap;
    private SessionContext sc;

    public StateMachine(EJBControllerLocalEJB ccejb, SessionContext sc) {
        this.ccejb = ccejb;
        this.sc = sc;
        attributeMap = new HashMap();
        actionMap = new HashMap();
    }

    public EventResponse processEvent(Event ev) throws EventException {
        String actionName = ev.getEJBActionClassName();
        EventResponse response = null;
        if (actionName  != null) {
            EJBAction action = null;
            try {
                 if (actionMap.get(actionName) != null) {
                    action = (EJBAction)actionMap.get(actionName);
                 } else {
                     action = (EJBAction)Class.forName(actionName).newInstance();
                     actionMap.put(actionName, action);
             }
            } catch (Exception ex) {
                System.err.println("StateMachine: error loading " + actionName + " :" + ex);
            }
            if (action != null) {
                action.init(this);
                // do the magic
                action.doStart();
                response = action.perform(ev);
                action.doEnd();
            }
        }
        return response;
    }

    public void setAttribute(String key, Object value) {
        attributeMap.put(key, value);
    }

    public Object getAttribute(String key) {
        return attributeMap.get(key);
    }

    public EJBControllerLocalEJB getEJBController() {
        return ccejb;
    }

    public SessionContext getSessionContext() {
        return sc;
    }

}