org.josef.web.servlet

Class GZipFilter

java.lang.Object

org.josef.web.servlet.GZipFilter

All Implemented Interfaces:

javax.servlet.Filter

public class GZipFilter
extends Object
implements javax.servlet.Filter

Filter that zips the response, provided that the client accepts gzip encoding.
To use this filter in your application, add the following xml to your web.xml.

 <filter>
   <filter-name>GZipFilter</filter-name>
   <filter-class>org.josef.web.servlet.GZipFilter</filter-class>
   <init-param>
     <param-name>threshold</param-name>
     <param-value>2048</param-value>
   </init-param>
 </filter>
 <filter-mapping>
   <filter-name>GZipFilter</filter-name>
   <url-pattern>/demo/*</url-pattern>
 </filter-mapping>
 

Technical note: This filter does not use an annotation on purpose! You probably want to configure the url pattern and determine the threshold for compression. The threshold is optional and defaults to 1024 bytes (1K). So every response larger than 1K is compressed while smaller ones are untouched.

Author:

Jayson Falkner

Constructor Summary

Constructors

Constructor and Description
GZipFilter()

Method Summary

Modifier and Type	Method and Description
void	destroy() Destroys this filter by doing absolutely nothing.
void	doFilter(javax.servlet.ServletRequest servletRequest, javax.servlet.ServletResponse servletResponse, javax.servlet.FilterChain filterChain) Zips the response when the client accepts gzip encoding and the size of the response exceeds the threshold.
void	init(javax.servlet.FilterConfig filterConfig) Initializes this filter by getting the threshold init parameter.

Methods inherited from class java.lang.Object

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

Constructor Detail

GZipFilter

public GZipFilter()

Method Detail

init

public void init(javax.servlet.FilterConfig filterConfig)

Initializes this filter by getting the threshold init parameter. When the threshold parameter is missing, a warning is logged and a default of 1024 bytes is used.

Specified by:

init in interface javax.servlet.Filter

Parameters:

filterConfig - The Filter configuration.

doFilter

public void doFilter(javax.servlet.ServletRequest servletRequest,
                     javax.servlet.ServletResponse servletResponse,
                     javax.servlet.FilterChain filterChain)
              throws javax.servlet.ServletException,
                     IOException

Zips the response when the client accepts gzip encoding and the size of the response exceeds the threshold.

Specified by:

doFilter in interface javax.servlet.Filter

Parameters:

servletRequest - The servlet request.

servletResponse - The servlet response.

filterChain - The filter chain.

Throws:

javax.servlet.ServletException - When another filter in the chain throws this exception.

IOException - When the response could not be written.

destroy

public void destroy()

Destroys this filter by doing absolutely nothing.

Specified by:

destroy in interface javax.servlet.Filter