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();
      }
  }