jsp.java

webwork source

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

import webwork.action.Action;
import webwork.action.ActionSupport;
import webwork.action.ActionContext;
import webwork.action.factory.ActionFactory;

import javax.servlet.RequestDispatcher;
import javax.servlet.ServletOutputStream;
import javax.servlet.http.Cookie;
import javax.servlet.http.HttpServletResponse;
import javax.servlet.http.HttpServletResponseWrapper;
import java.io.IOException;
import java.io.PrintWriter;
import java.io.StringWriter;
import java.util.Locale;

import org.apache.commons.logging.*;

/**
 *	JSP execution wrapper. This action allows JSP pages to be executed as actions.
 *
 * The JSP page should set the request attribute "result" to the result status.
 * Well defined result status constants are defined in the Action interface.
 *
 *	@see webwork.action.Action
 *	@author Rickard 謆erg ([e-mail])
 *	@version $Revision: 1.10 $
 */
public class JSP
   extends ActionSupport
{
   // Static --------------------------------------------------------

   // Attributes ----------------------------------------------------
   String pageName;
   RequestDispatcher dispatcher;

   /**
    * Get name of the page that is wrapped
    */
   public String getPage()
   {
      return pageName;
   }

   /**
    * Set the name of the page that is to be executed.
    *
    * @see webwork.action.factory.JspActionFactoryProxy
    */
   public void setPage(String aPageName)
   {
      pageName = aPageName;
      dispatcher = ActionContext.getContext().getRequest().getRequestDispatcher(aPageName);
   }

   // Action implementation -----------------------------------------
   /**
    * Execute the wrapper. This will forward to the given JSP-page,
    * which then can execute arbitrary code (possibly using tag libraries).
    * The JSP page should then set the "result" request attribute to the
    * result state of the execution.
    *
    * Any content generated by the JSP page will be thrown away.
    */
   public String execute()
      throws Exception
   {
      // Get servlet context
      ActionContext ctx = ActionContext.getContext();

      // Create wrapper which ignores all content-modifying calls
      HttpServletResponse res = new WrapperHttpServletResponse(ctx.getResponse());

      String oldResult = (String)ctx.getRequest().getAttribute("result");

      // Execute JSP
      dispatcher.forward(ctx.getRequest(), res);

      // Extract the result
      String result =(String)ctx.getRequest().getAttribute("result");

      // Default to success
      if (result == null)
         result = Action.SUCCESS;

      // Restore request attribute
      if (oldResult == null)
         ctx.getRequest().removeAttribute("result");
      else
         ctx.getRequest().setAttribute("result", oldResult);
      return result;
   }

   // Public --------------------------------------------------------

   // Protected -----------------------------------------------------

   // Inner classes -------------------------------------------------
   /**
    * Response wrapper. Delegate to real response, but
    * ignore all content modifying calls and return
    * dummies instead of real streams.
    */
   public class WrapperHttpServletResponse
      extends HttpServletResponseWrapper
   {
      WrapperHttpServletResponse(HttpServletResponse aResponse)
      {
         super(aResponse);
      }

      public void flushBuffer() throws IOException
      {
         // Ignore
      }

      public ServletOutputStream getOutputStream() throws IOException
      {
         return new ServletOutputStream()
         {
            public void write(int b) throws IOException
            {
               // Throw away
            }
         };
      }

      public PrintWriter getWriter() throws IOException
      {
         return new PrintWriter(new StringWriter());
      }

      public void resetBuffer()
      {
         //response.resetBuffer();
      }

      public void setContentType(String s)
      {
         // Ignore
      }
   }
}