org.jumpmind.symmetric.web.compression
Class CompressionFilter

java.lang.Object
  org.jumpmind.symmetric.web.compression.CompressionFilter

All Implemented Interfaces:

javax.servlet.Filter

public class CompressionFilter
extends java.lang.Object
implements javax.servlet.Filter

Implementation of javax.servlet.Filter used to compress the ServletResponse if it is bigger than a threshold. This package is derived from the Jakarta Tomcat examples compression filter and is distributed in SymmetricDS for convenience.

Version:

$Revision: 466607 $, $Date: 2006-10-21 17:09:50 -0600 (Sat, 21 Oct 2006) $

Author:

Amy Roh, Dmitri Valdin

Constructor Summary

CompressionFilter()

Method Summary

void	destroy() Take this filter out of service.
void	doFilter(javax.servlet.ServletRequest request, javax.servlet.ServletResponse response, javax.servlet.FilterChain chain) The doFilter method of the Filter is called by the container each time a request/response pair is passed through the chain due to a client request for a resource at the end of the chain.
javax.servlet.FilterConfig	getFilterConfig() Return filter config Required by Weblogic 6.1
void	init(javax.servlet.FilterConfig filterConfig) Place this filter into service.
void	setFilterConfig(javax.servlet.FilterConfig filterConfig) Set filter config This function is equivalent to init.

Methods inherited from class java.lang.Object

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

Constructor Detail

CompressionFilter

public CompressionFilter()

Method Detail

init

public void init(javax.servlet.FilterConfig filterConfig)

Place this filter into service.

Specified by:

init in interface javax.servlet.Filter

Parameters:

filterConfig - The filter configuration object

destroy

public void destroy()

Take this filter out of service.

Specified by:

destroy in interface javax.servlet.Filter

doFilter

public void doFilter(javax.servlet.ServletRequest request,
                     javax.servlet.ServletResponse response,
                     javax.servlet.FilterChain chain)
              throws java.io.IOException,
                     javax.servlet.ServletException

The doFilter method of the Filter is called by the container each time a request/response pair is passed through the chain due to a client request for a resource at the end of the chain. The FilterChain passed into this method allows the Filter to pass on the request and response to the next entity in the chain.

This method first examines the request to check whether the client support compression.
It simply just pass the request and response if there is no support for compression.
If the compression support is available, it creates a CompressionServletResponseWrapper object which compresses the content and modifies the header if the content length is big enough. It then invokes the next entity in the chain using the FilterChain object (chain.doFilter()),

Specified by:

doFilter in interface javax.servlet.Filter

Throws:

java.io.IOException

javax.servlet.ServletException

setFilterConfig

public void setFilterConfig(javax.servlet.FilterConfig filterConfig)

Set filter config This function is equivalent to init. Required by Weblogic 6.1

Parameters:

filterConfig - The filter configuration object

getFilterConfig

public javax.servlet.FilterConfig getFilterConfig()

Return filter config Required by Weblogic 6.1