org.displaytag.filter: public class: ResponseOverrideFilter

org.displaytag.filter
public class: ResponseOverrideFilter [javadoc | source]

java.lang.Object
   org.displaytag.filter.ResponseOverrideFilter

All Implemented Interfaces:
Filter

Allow the author of an included JSP page to reset the content type to something else (like a binary stream), and then write the new info back as the exclusive response, clearing the buffers of all previously added content.

This filter allows TableTag users to perform exports from pages that are run as includes, such as from Struts or a jsp:include. If that is your intention, just add this Filter to your web.xml and map it to the appropriate requests, using something like:

<filter>
<filter-name>ResponseOverrideFilter</filter-name>
<filter-class>org.displaytag.filter.ResponseOverrideFilter</filter-class>
</filter>
<filter-mapping>
<filter-name>ResponseOverrideFilter</filter-name>
<url-pattern>*.do</url-pattern>
</filter-mapping>
<filter-mapping>
<filter-name>ResponseOverrideFilter</filter-name>
<url-pattern>*.jsp</url-pattern>
</filter-mapping>

By default the filter buffers all the export content before writing it out. You can set an optional parameter buffer to false to make the filter write directly to the output stream. This could be faster and uses less memory, but the content length will not be set.

<filter>
<filter-name>ResponseOverrideFilter</filter-name>
<filter-class>org.displaytag.filter.ResponseOverrideFilter</filter-class>
<init-param>
<param-name>buffer</param-name>
<param-value>false</param-value>
</init-param>
</filter>

author: rapruitt -

author: Fabrizio - Giustina

version: $ - Revision: 1081 $ ($Author: fgiust $)

Method from org.displaytag.filter.ResponseOverrideFilter Summary:
destroy, doFilter, init

Methods from java.lang.Object:
equals, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Method from org.displaytag.filter.ResponseOverrideFilter Detail:
public void destroy() { // nothing to destroy } {@inheritDoc}
public void doFilter(ServletRequest servletRequest, ServletResponse servletResponse, FilterChain filterChain) throws IOException, ServletException { if (servletRequest.getParameter(TableTagParameters.PARAMETER_EXPORTING) == null) { if (log.isDebugEnabled()) { log.debug(Messages.getString("ResponseOverrideFilter.parameternotfound")); //$NON-NLS-1$ } // don't filter! filterChain.doFilter(servletRequest, servletResponse); return; } HttpServletRequest request = (HttpServletRequest) servletRequest; BufferedResponseWrapper wrapper = new BufferedResponseWrapper13Impl((HttpServletResponse) servletResponse); Map contentBean = new HashMap(4); if (buffer) { contentBean.put(TableTagParameters.BEAN_BUFFER, Boolean.TRUE); } request.setAttribute(TableTag.FILTER_CONTENT_OVERRIDE_BODY, contentBean); filterChain.doFilter(request, wrapper); ExportDelegate.writeExport((HttpServletResponse) servletResponse, servletRequest, wrapper); } {@inheritDoc}
public void init(FilterConfig filterConfig) { log = LogFactory.getLog(ResponseOverrideFilter.class); String bufferParam = filterConfig.getInitParameter("buffer"); if (log.isDebugEnabled()) { log.debug("bufferParam=" + bufferParam); } buffer = bufferParam == null \|\| StringUtils.equalsIgnoreCase("true", bufferParam); log.info("Filter initialized. Response buffering is " + (buffer ? "enabled" : "disabled")); } {@inheritDoc}

Method from org.displaytag.filter.ResponseOverrideFilter Detail:

 public  void destroy() {
        // nothing to destroy
}

{@inheritDoc}

 public  void doFilter(ServletRequest servletRequest,
    ServletResponse servletResponse,
    FilterChain filterChain) throws IOException, ServletException {
        if (servletRequest.getParameter(TableTagParameters.PARAMETER_EXPORTING) == null)
        {
            if (log.isDebugEnabled())
            {
                log.debug(Messages.getString("ResponseOverrideFilter.parameternotfound")); //$NON-NLS-1$
            }
            // don't filter!
            filterChain.doFilter(servletRequest, servletResponse);
            return;
        }
        HttpServletRequest request = (HttpServletRequest) servletRequest;
        BufferedResponseWrapper wrapper = new BufferedResponseWrapper13Impl((HttpServletResponse) servletResponse);
        Map contentBean = new HashMap(4);
        if (buffer)
        {
            contentBean.put(TableTagParameters.BEAN_BUFFER, Boolean.TRUE);
        }
        request.setAttribute(TableTag.FILTER_CONTENT_OVERRIDE_BODY, contentBean);
        filterChain.doFilter(request, wrapper);
        ExportDelegate.writeExport((HttpServletResponse) servletResponse, servletRequest, wrapper);
}

{@inheritDoc}

 public  void init(FilterConfig filterConfig) {
          
        log = LogFactory.getLog(ResponseOverrideFilter.class);
        String bufferParam = filterConfig.getInitParameter("buffer");
        if (log.isDebugEnabled())
        {
            log.debug("bufferParam=" + bufferParam);
        }
        buffer = bufferParam == null || StringUtils.equalsIgnoreCase("true", bufferParam);
        log.info("Filter initialized. Response buffering is " + (buffer ? "enabled" : "disabled"));
}

{@inheritDoc}