package org.andromda.cartridges.jsf.renderkit;
   
   import java.io.IOException;
   import java.io.InputStream;
   import java.io.OutputStream;
   
   import javax.faces.component.UIComponent;
   import javax.faces.context.FacesContext;
   import javax.faces.render.Renderer;
  import javax.servlet.http.HttpServletResponse;
  
  import org.andromda.cartridges.jsf.component.BinaryFile;
  import org.apache.commons.lang.StringUtils;
  
  
  /**
   * A custom renderer for rendering a binary file.
   *
   * @author Chad Brandon
   */
  public class BinaryFileRenderer
      extends Renderer
  {
      /**
       * Gets the current response instance.
       *
       * @return the current response.
       */
      private HttpServletResponse getResponse(final FacesContext context)
      {
          return (HttpServletResponse)context.getExternalContext().getResponse();
      }
  
      private static final int BUFFER_SIZE = 4096;
  
      @Override
      public void encodeBegin(
          FacesContext context,
          UIComponent component)
          throws IOException
      {
          final BinaryFile fileComponent = (BinaryFile)component;
          if (fileComponent.isRendered())
          {
              final HttpServletResponse response = this.getResponse(context);
              final OutputStream stream = response.getOutputStream();
  
              // - reset the response to clear out any any headers (i.e. so
              //   the user doesn't get "unable to open..." when using IE.)
              response.reset();
              final String fileName = fileComponent.getFileName();
              if (fileComponent.isPrompt() && fileName != null && fileName.trim().length() > 0)
              {
                  response.addHeader(
                      "Content-disposition",
                      "attachment; filename=\"" + fileName + '"');
              }
  
              Object value = fileComponent.getValue();
              final String contentType = fileComponent.getContentType();
              // - for IE we need to set the content type, content length and buffer size and
              //   then the flush the response right away because it seems as if there is any lag time
              //   IE just displays a blank page. With mozilla based clients reports display correctly regardless.
              if (StringUtils.isNotBlank(contentType))
              {
                  response.setContentType(contentType);
              }
              final String encoding = fileComponent.getEncoding();
              if (StringUtils.isNotBlank(encoding))
              {
                  response.setCharacterEncoding(encoding);
              }
              if (value != null)
              {
                  if (value instanceof String)
                  {
                      value = StringUtils.isNotBlank(encoding) ? ((String)value).getBytes(encoding) : ((String)value).getBytes();
                  }
                  if (value instanceof byte[])
                  {
                      byte[] file = (byte[])value;
                      response.setBufferSize(file.length);
                      response.setContentLength(file.length);
                      response.flushBuffer();
                      stream.write(file);
                  }
                  else if (value instanceof InputStream)
                  {
                      final InputStream report = (InputStream)value;
                      final byte[] buffer = new byte[BUFFER_SIZE];
                      response.setBufferSize(BUFFER_SIZE);
                      response.flushBuffer();
                      for (int ctr = 0; (ctr = report.read(buffer)) > 0;)
                      {
                          stream.write(buffer, 0, ctr);
                      }
                      stream.flush();
                  }
              }
         }
     }
 
     @Override
     public void encodeEnd(
         final FacesContext context,
         final UIComponent component)
         throws IOException
     {
         final BinaryFile fileComponent = (BinaryFile)component;
         if (fileComponent.isRendered())
         {
             final HttpServletResponse response = this.getResponse(context);
             final OutputStream stream = response.getOutputStream();
             stream.flush();
             stream.close();
         }
     }
 }