net.sf.ehcache.constructs.web.filter
Class PageFragmentCachingFilter

java.lang.Object
  net.sf.ehcache.constructs.web.filter.Filter
      net.sf.ehcache.constructs.web.filter.CachingFilter
          net.sf.ehcache.constructs.web.filter.PageFragmentCachingFilter

All Implemented Interfaces:

javax.servlet.Filter

Direct Known Subclasses:

SimplePageFragmentCachingFilter

public abstract class PageFragmentCachingFilter
extends CachingFilter

A Template for a page caching filter that is designed for "included" pages, eg: jsp:includes. This filter differs from the CachingFilter in that it is not writing an entire response to the output stream.

This class should be sub-classed for each included page to be cached.

Filter Mappings need to be set up for a cache to have effect.

Version:

$Id: PageFragmentCachingFilter.java 744 2008-08-16 20:10:49Z gregluck $

Author:

Greg Luck

Field Summary

Fields inherited from class net.sf.ehcache.constructs.web.filter.CachingFilter

blockingCache, cacheName

Fields inherited from class net.sf.ehcache.constructs.web.filter.Filter

exceptionsToLogDifferently, filterConfig, NO_FILTER, suppressStackTraces

Constructor Summary

PageFragmentCachingFilter()

Method Summary

protected PageInfo	buildPage(javax.servlet.http.HttpServletRequest request, javax.servlet.http.HttpServletResponse response, javax.servlet.FilterChain chain) Builds the PageInfo object by passing the request along the filter chain
protected void	doFilter(javax.servlet.http.HttpServletRequest request, javax.servlet.http.HttpServletResponse response, javax.servlet.FilterChain chain) Performs the filtering for a request.
protected void	writeResponse(javax.servlet.http.HttpServletResponse response, PageInfo pageInfo) Assembles a response from a cached page include.

Methods inherited from class net.sf.ehcache.constructs.web.filter.CachingFilter

buildPageInfo, calculateKey, checkNoReentry, doDestroy, doInit, getCacheManager, getCacheName, setCacheNameIfAnyConfigured, setContentType, setCookies, setHeaders, setStatus, writeContent, writeResponse

Methods inherited from class net.sf.ehcache.constructs.web.filter.Filter

acceptsEncoding, acceptsGzipEncoding, destroy, doFilter, filterNotDisabled, getFilterConfig, init, logRequestHeaders, processInitParams

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Constructor Detail

PageFragmentCachingFilter

public PageFragmentCachingFilter()

Method Detail

doFilter

protected void doFilter(javax.servlet.http.HttpServletRequest request,
                        javax.servlet.http.HttpServletResponse response,
                        javax.servlet.FilterChain chain)
                 throws java.lang.Exception

Performs the filtering for a request.

Overrides:

doFilter in class CachingFilter

Throws:

AlreadyGzippedException - if a double gzip is attempted

AlreadyCommittedException - if the response was committed on the way in or the on the way back

FilterNonReentrantException - if an attempt is made to reenter this filter in the same request.

net.sf.ehcache.constructs.blocking.LockTimeoutException - if this request is waiting on another that is populating the cache entry and timeouts while waiting. Only occurs if the BlockingCache has a timeout set.

java.lang.Exception - for all other exceptions. They will be caught and logged in Filter.doFilter(javax.servlet.ServletRequest, javax.servlet.ServletResponse, javax.servlet.FilterChain)

buildPage

protected PageInfo buildPage(javax.servlet.http.HttpServletRequest request,
                             javax.servlet.http.HttpServletResponse response,
                             javax.servlet.FilterChain chain)
                      throws AlreadyGzippedException,
                             java.lang.Exception

Builds the PageInfo object by passing the request along the filter chain

Overrides:

buildPage in class CachingFilter

Parameters:

request -

response -

chain -

Returns:

a Serializable value object for the page or page fragment

Throws:

AlreadyGzippedException - if an attempt is made to double gzip the body

java.lang.Exception

writeResponse

protected void writeResponse(javax.servlet.http.HttpServletResponse response,
                             PageInfo pageInfo)
                      throws java.io.IOException

Assembles a response from a cached page include. These responses are never gzipped The content length should not be set in the response, because it is a fragment of a page. Don't write any headers at all.

Throws:

java.io.IOException