package com.atlassian.plugin.servlet;
   
   import com.atlassian.plugin.elements.ResourceLocation;
   import org.apache.commons.lang.StringUtils;
   
   import javax.servlet.ServletException;
   import javax.servlet.http.HttpServletRequest;
   import javax.servlet.http.HttpServletResponse;
   import java.io.IOException;
  import java.io.OutputStream;
  
  /**
   * A DownloadableResource that simply forwards the request to the given location.
   * This should be used to reference dynamic resources available in the web application e.g dwr js files
   */
  public class ForwardableResource implements DownloadableResource
  {
      private ResourceLocation resourceLocation;
  
      public ForwardableResource(ResourceLocation resourceLocation)
      {
          this.resourceLocation = resourceLocation;
      }
  
      public boolean isResourceModified(HttpServletRequest request, HttpServletResponse response)
      {
          return true;
      }
  
      public void serveResource(HttpServletRequest request, HttpServletResponse response) throws DownloadException
      {
          try
          {
              String type = getContentType();
              if(StringUtils.isNotBlank(type))
              {
                  response.setContentType(type); // this will be used if content-type is not set by the forward handler, e.g. for webapp content in Tomcat
              }
              request.getRequestDispatcher(getLocation()).forward(request, response);
          }
          catch(ServletException e)
          {
              throw new DownloadException(e.getMessage());
          }
          catch (IOException ioe)
          {
              throw new DownloadException(ioe.getMessage());
          }
      }
  
      /**
       * Not implemented by a <code>ForwardableResource</code>. The supplied OutputStream will not be modified.
       */
      public void streamResource(OutputStream out)
      {
          return;
      }
  
      public String getContentType()
      {
          return resourceLocation.getContentType();
      }
  
      protected String getLocation()
      {
          return resourceLocation.getLocation();
      }
  
      @Override
      public String toString()
      {
          return "Forwardable Resource: " + resourceLocation.getLocation();
      }
  }