clientservletdispatcher.java

webwork source

/*
 * WebWork, Web Application Framework
 *
 * Distributable under Apache license.
 * See terms of license at opensource.org
 */
package webwork.dispatcher;

import org.apache.commons.logging.*;
import webwork.action.Action;
import webwork.action.ServletActionContext;
import webwork.action.client.ActionResult;
import webwork.action.factory.ActionFactory;
import webwork.action.factory.ContextActionFactoryProxy;

import javax.servlet.ServletConfig;
import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import java.io.*;

/**
 * Dispatcher servlet that can be invoked by remote clients, such as applets.
 *
 * @author Rickard 謆erg ([e-mail])
 * @version $Revision: 1.14 $
 */
public class ClientServletDispatcher
  extends HttpServlet
{
   // Attributes ----------------------------------------------------
   protected static final Log log = LogFactory.getLog(ClientServletDispatcher.class);

   // HttpServlet overrides -----------------------------------------
   /**
    * Initialize dispatcher servlet
    * @exception   ServletException
    */
   public void init(ServletConfig config)
     throws ServletException
   {
      super.init(config);
      log.info("Remote Action dispatcher initialized");
   }

   /**
    * Service a request
    * @exception   ServletException
    */
   public void service(HttpServletRequest aRequest, HttpServletResponse aResponse)
     throws ServletException
   {
      try
      {
         ObjectInputStream in = createObjectInputStream(aRequest.getInputStream());
         final Action action = (Action)in.readObject();

         ServletActionContext.setContext(aRequest, aResponse, getServletContext(), null);

         // Give the action its proper context
         new ContextActionFactoryProxy(new ActionFactory()
         {
            public Action getActionImpl(String aName) throws Exception
            {
               return action;
            }
         }).getActionImpl(null);

         // Execute action
         ActionResult actionResult;

         try
         {
            String result = action.execute();

            actionResult = new ActionResult(action, result);
         } catch (Exception e)
         {
            actionResult = new ActionResult(action, null);
            actionResult.setException(e);
         }

         ObjectOutputStream out = createObjectOutputStream(aResponse.getOutputStream());

         out.writeObject(actionResult);
         out.flush();
      } catch (Exception e)
      {
         e.printStackTrace();
         throw new ServletException(e);
      }
   }

   // Protected -----------------------------------------------------
   /**
    * Create an object input stream that wraps the URL connection stream.
    *
    * This method can be overriden in order to create custom streams.
    *
    * @param in the underlying stream. It is buffered
    * @return an object input stream
    * @throws IOException
    */
   protected ObjectInputStream createObjectInputStream(InputStream in)
      throws IOException
   {
      return new ObjectInputStream(in);
   }

   /**
    * Create an object input stream that wraps the URL connection stream.
    *
    * This method can be overriden in order to create custom streams.
    *
    * @param out The OutputStream to wrap
    * @return an ObjectOutputStream wrapping the specified OutputStream
    * @throws IOException
    */
   protected ObjectOutputStream createObjectOutputStream(OutputStream out)
      throws IOException
   {
      return new ObjectOutputStream(out);
   }
}