clientstateflowhandler.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.flow.handlers;

import java.io.ByteArrayInputStream;
import java.io.ObjectInputStream;
import java.util.Map;
import java.util.Iterator;
import java.util.HashMap;

// Apache Commons- Tag-Lib Imports
import org.apache.commons.codec.base64.Base64;

// J2EE imports
import javax.servlet.http.HttpServletRequest;

// WAF imports
import com.sun.j2ee.blueprints.waf.controller.web.flow.FlowHandler;
import com.sun.j2ee.blueprints.waf.controller.web.flow.FlowHandlerException;

/**
 * This class de-serializes Base64 encoded parameters encoded into a web page using the
 * ClientCacheLinkTag.
 *
*/
public class ClientStateFlowHandler implements FlowHandler {

    public void doStart(HttpServletRequest request){
    }

    public String processFlow(HttpServletRequest request)
        throws FlowHandlerException {


        String forwardScreen = request.getParameter("referring_screen");
        // de-serialize the request attributes.
        Map params = (Map)request.getParameterMap();
        HashMap newParams = new HashMap();
        String cacheId= request.getParameter("cacheId");
        if (!params.isEmpty()) {
            Iterator it = params.keySet().iterator();
            // put the request attributes stored in the session in the request
            while (it.hasNext()) {
                String key = (String)it.next();
                if (key.startsWith(cacheId + "_attribute_")) {
                    String[] values = (String[])params.get(key);
                    String valueString = values[0];
                    byte[] bytes  = Base64.decode(valueString.getBytes());
                    try {
                        ObjectInputStream ois = new ObjectInputStream(new ByteArrayInputStream(bytes));
                        Object requestObject = requestObject = ois.readObject();
                        ois.close();
                        // put the de-serialized object back into the request
                        String requestObjectKey = key.substring((cacheId + "_attribute_").length(), key.length());
                        request.setAttribute(requestObjectKey, requestObject);
                    } catch (java.io.OptionalDataException ode) {
                        System.err.println("ClientCacheLinkFlowHandler caught: " + ode);
                    } catch (java.lang.ClassNotFoundException cnfe) {
                        System.err.println("ClientCacheLinkFlowHandler caught: " + cnfe);
                    } catch (java.io.IOException iox) {
                        System.err.println("ClientCacheLinkFlowHandler caught: " + iox);
                    }
                }
            }
        }
        return forwardScreen;
    }


    public void doEnd(HttpServletRequest request) {
    }

}