asquare.gwt.tk.server
Class GWTCacheFilter

java.lang.Object
  asquare.gwt.tk.server.GWTCacheFilter

All Implemented Interfaces:

Filter

public class GWTCacheFilter
extends Object
implements Filter

This is a filter which enforces proper caching of the generated GWT script files. It requires that serve your GWT application via a Java servlet container.

To use, add the jar to WEB-INF/lib and add the following to your deployment descriptor (web.xml):

 <filter>
   <filter-name>GWTCacheFilter</filter-name>
   <filter-class>asquare.gwt.tk.server.GWTCacheFilter</filter-class>
   <description>Enforces proper caching of GWT script files</description>
 </filter>
 
 <filter-mapping>
   <filter-name>GWTCacheFilter</filter-name>
   <url-pattern>*.html</url-pattern>
 </filter-mapping>

By default, files ending in .cache.html are cached and files ending in .nocache.html are not cached. You can override the defaults by specifying file name patterns in filter init-params. The pattern is parsed as a JDK regular expression. The defaults are below:

 <init-param>
   <param-name>forceDontCache</param-name>
   <param-value>.+\.nocache.html</param-value>
 </init-param>
 <init-param>
   <param-name>forceCache</param-name>
   <param-value>.+\.cache.html</param-value>
 </init-param>

Usage notes

• You can verify that the filter is being applied with Firefox's Web Developer Extension. Click Tools > Web Developer > Information > View Response Headers.
• If you are running an Apache httpd/Jk/Tomcat server configuration you need to ensure that Tomcat is serving HTML files, otherwise the filter will not be applied.
• One reason that this filter exists is that you cannot use *.nocache.html or *.cache.html for url patterns. According to the 2.3 servlet spec, an extension is defined as the characters after the last period.
• The header is modified before passing control down the filter chain.

See Also:

Cache-control directive, Expires directive, Pragma directive

Field Summary

static String	DEFAULT_FORCECACHE The default value of the forceDontCache init-param.
static String	DEFAULT_FORCEDONTCACHE The default value of the forceCache init-param.
static String	INITPARAM_FORCECACHE The name of the filter init-param which specifies files to cache.
static String	INITPARAM_FORCEDONTCACHE The name of the filter init-param which specifies files not to cache.

Constructor Summary

GWTCacheFilter()

Method Summary

void	destroy()
void	doFilter(ServletRequest request, ServletResponse response, FilterChain chain)
void	init(FilterConfig filterConfig)

Methods inherited from class java.lang.Object

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

Field Detail

INITPARAM_FORCEDONTCACHE

public static final String INITPARAM_FORCEDONTCACHE

The name of the filter init-param which specifies files not to cache. The name is "forceDontCache".

See Also:

Constant Field Values

INITPARAM_FORCECACHE

public static final String INITPARAM_FORCECACHE

The name of the filter init-param which specifies files to cache. The name is "forceCache".

See Also:

Constant Field Values

DEFAULT_FORCEDONTCACHE

public static final String DEFAULT_FORCEDONTCACHE

The default value of the forceCache init-param. The value is ".+\\.nocache.html".

See Also:

Constant Field Values

DEFAULT_FORCECACHE

public static final String DEFAULT_FORCECACHE

The default value of the forceDontCache init-param. The value is ".+\\.cache.html".

See Also:

Constant Field Values

Constructor Detail

GWTCacheFilter

public GWTCacheFilter()

Method Detail

init

public void init(FilterConfig filterConfig)
          throws ServletException

Specified by:

init in interface Filter

Throws:

ServletException

doFilter

public void doFilter(ServletRequest request,
                     ServletResponse response,
                     FilterChain chain)
              throws IOException,
                     ServletException

Specified by:

doFilter in interface Filter

Throws:

IOException

ServletException

destroy

public void destroy()

Specified by:

destroy in interface Filter