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ServletDispatcherResult.javaAPI DocExample5505Mon Jul 23 13:26:38 BST 2007org.apache.struts2.dispatcher

ServletDispatcherResult

public class ServletDispatcherResult extends StrutsResultSupport
Includes or forwards to a view (usually a jsp). Behind the scenes Struts will use a RequestDispatcher, where the target servlet/JSP receives the same request/response objects as the original servlet/JSP. Therefore, you can pass data between them using request.setAttribute() - the Struts action is available.

There are three possible ways the result can be executed:

  • If we are in the scope of a JSP (a PageContext is available), PageContext's {@link PageContext#include(String) include} method is called.
  • If there is no PageContext and we're not in any sort of include (there is no "javax.servlet.include.servlet_path" in the request attributes), then a call to {@link RequestDispatcher#forward(javax.servlet.ServletRequest, javax.servlet.ServletResponse) forward} is made.
  • Otherwise, {@link RequestDispatcher#include(javax.servlet.ServletRequest, javax.servlet.ServletResponse) include} is called.
This result type takes the following parameters:
  • location (default) - the location to go to after execution (ex. jsp).
  • parse - true by default. If set to false, the location param will not be parsed for Ognl expressions.
Example: 

<result name="success" type="dispatcher">
<param name="location">foo.jsp</param>
</result>
This result follows the same rules from {@link StrutsResultSupport}.
see
javax.servlet.RequestDispatcher

Fields Summary
private static final long
serialVersionUID
private static final Log
log
Constructors Summary
public ServletDispatcherResult()


      
        super();
public ServletDispatcherResult(String location)

        super(location);
Methods Summary
public voiddoExecute(java.lang.String finalLocation, com.opensymphony.xwork2.ActionInvocation invocation)
Dispatches to the given location. Does its forward via a RequestDispatcher. If the dispatch fails a 404 error will be sent back in the http response.

param
finalLocation the location to dispatch to.
param
invocation the execution state of the action
throws
Exception if an error occurs. If the dispatch fails the error will go back via the HTTP request.

        if (log.isDebugEnabled()) {
            log.debug("Forwarding to location " + finalLocation);
        }

        PageContext pageContext = ServletActionContext.getPageContext();

        if (pageContext != null) {
            pageContext.include(finalLocation);
        } else {
            HttpServletRequest request = ServletActionContext.getRequest();
            HttpServletResponse response = ServletActionContext.getResponse();
            RequestDispatcher dispatcher = request.getRequestDispatcher(finalLocation);

            // if the view doesn't exist, let's do a 404
            if (dispatcher == null) {
                response.sendError(404, "result '" + finalLocation + "' not found");

                return;
            }

            // If we're included, then include the view
            // Otherwise do forward
            // This allow the page to, for example, set content type
            if (!response.isCommitted() && (request.getAttribute("javax.servlet.include.servlet_path") == null)) {
                request.setAttribute("struts.view_uri", finalLocation);
                request.setAttribute("struts.request_uri", request.getRequestURI());

                dispatcher.forward(request, response);
            } else {
                dispatcher.include(request, response);
            }
        }