Package com.levigo.jadice.web.server.filter

Class CacheFilter

java.lang.Object

com.levigo.jadice.web.server.filter.CacheFilter

All Implemented Interfaces:

jakarta.servlet.Filter

@WebFilter(description="Enable caching for cacheable GWT resources",
           displayName="jadice web toolkit GWT resource caching",
           filterName="jwtCacheFilter",
           urlPatterns="/*",
           asyncSupported=true)
public class CacheFilter
extends Object
implements jakarta.servlet.Filter

This Filter adds the required HTTP Headers to the to the HttpServletResponse to allow the browser to cache the requested resource. By default this filter is applied to GWT's *.cache.* files. If any of these resources is requested the filter will inject the following HTTP headers into the response:

• Cache-Control: public, max-age=cacheExpirySeconds
• Expires: System.currentTimeMillis() + cacheExpirySeconds * 1000
• Pragma will be deleted, if existing

cacheExpirySeconds is a configurable value that can be set through the filter initialization parameter "cache-expiry-seconds". If the initialization parameter is omitted the default value 15552000L (180 days) will be used instead.

Field Summary

Fields

Modifier and Type	Field	Description
static final long	CACHE_EXPIRY_SECONDS_DEFAULT	Default value used when initialization parameter PARAM_CACHE_EXPIRY_SECONDS is not given.
static final String	PARAM_CACHE_EXPIRY_SECONDS	Name of initialization parameter.

Constructor Summary

Constructors

Constructor	Description
CacheFilter()	Default constructor.
CacheFilter(String... additionalPatterns)	Constructs a filter instance with additional patterns.

Method Summary

Modifier and Type	Method	Description
protected boolean	appliesTo(String path)	Checks whether this filter applies to the given path.
void	destroy()
void	doFilter(jakarta.servlet.ServletRequest request, jakarta.servlet.ServletResponse response, jakarta.servlet.FilterChain chain)
void	init(jakarta.servlet.FilterConfig filterConfig)

Methods inherited from class java.lang.Object

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

Field Details

PARAM_CACHE_EXPIRY_SECONDS

public static final String PARAM_CACHE_EXPIRY_SECONDS

Name of initialization parameter.

See Also:

• Constant Field Values

CACHE_EXPIRY_SECONDS_DEFAULT

public static final long CACHE_EXPIRY_SECONDS_DEFAULT

Default value used when initialization parameter PARAM_CACHE_EXPIRY_SECONDS is not given.

See Also:

• Constant Field Values

Constructor Details

CacheFilter

public CacheFilter()

Default constructor.

CacheFilter

public CacheFilter(String... additionalPatterns)

Constructs a filter instance with additional patterns.

Parameters:

additionalPatterns - regular expressions

Method Details

init

public void init(jakarta.servlet.FilterConfig filterConfig)
          throws jakarta.servlet.ServletException

Specified by:

init in interface jakarta.servlet.Filter

Throws:

jakarta.servlet.ServletException

doFilter

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

Specified by:

doFilter in interface jakarta.servlet.Filter

Throws:

IOException

jakarta.servlet.ServletException

appliesTo

protected boolean appliesTo(String path)

Checks whether this filter applies to the given path.

Parameters:

path - path of the requested resource

Returns:

true if one of the patterns matches the given path

destroy

public void destroy()

Specified by:

destroy in interface jakarta.servlet.Filter