Package org.wso2.carbon.ui.filters.cache

Class AbstractCachePreventionFilter

java.lang.Object

org.wso2.carbon.ui.filters.cache.AbstractCachePreventionFilter

All Implemented Interfaces:

javax.servlet.Filter

Direct Known Subclasses:

ContentTypeBasedCachePreventionFilter, URLBasedCachePreventionFilter

public abstract class AbstractCachePreventionFilter
extends Object
implements javax.servlet.Filter

This filter implements browser/proxy cache prevention. It would prevent sensitive information being cached on web browsers and intermediate network devices that adhere to protocols HTTP 1.0 through HTTP 1.1. In order to accommodate future modifications to protocol specifications and introduction of custom cache prevention headers and values, the filter can also utilize headers and values that are defined in the web.xml file.

Since:

4.2.0

Constructor Summary

Constructors

Constructor	Description
AbstractCachePreventionFilter()

Method Summary

Modifier and Type	Method	Description
protected void	applyCachePreventionHeaders(javax.servlet.http.HttpServletResponse response)	Setting cache prevention headers to responses.
protected boolean	canApplyCachePreventionHeaders(String stringToBeMatched)	Checks for a match with the filtering pattern and the Content Type/ URL.
void	destroy()
abstract void	doFilter(javax.servlet.ServletRequest servletRequest, javax.servlet.ServletResponse servletResponse, javax.servlet.FilterChain filterChain)
void	init(javax.servlet.FilterConfig filterConfig)
protected void	initHeaders(javax.servlet.FilterConfig filterConfig)	This method will check for any headers defined in the web.xml.
protected void	initPatternsAndAction(javax.servlet.FilterConfig filterConfig)	Reading the filtering pattern and the action to be performed against the pattern from the web.xml.

Methods inherited from class java.lang.Object

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

Constructor Detail

AbstractCachePreventionFilter

public AbstractCachePreventionFilter()

Method Detail

init

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

Specified by:

init in interface javax.servlet.Filter

Throws:

javax.servlet.ServletException

initHeaders

protected void initHeaders(javax.servlet.FilterConfig filterConfig)
                    throws javax.servlet.ServletException

This method will check for any headers defined in the web.xml. If any headers are found in the web.xml, those headers with the corresponding values will be set to prevent caching. If any headers aren't found in the web.xml, the default headers with values will be set for cache prevention.

Parameters:

filterConfig - Configurations specific to this filter in the web.xml

Throws:

javax.servlet.ServletException

initPatternsAndAction

protected void initPatternsAndAction(javax.servlet.FilterConfig filterConfig)

Reading the filtering pattern and the action to be performed against the pattern from the web.xml. The pattern is a regex that could define content types or URLs. Multiple patterns can be defined in each new line.

Parameters:

filterConfig - Configurations specific to this filter in the web.xml

canApplyCachePreventionHeaders

protected boolean canApplyCachePreventionHeaders(String stringToBeMatched)

Checks for a match with the filtering pattern and the Content Type/ URL.

Parameters:

stringToBeMatched - Requested URL or the Content Type in the response

Returns:

true for either to set headers for a match, or skip setting headers to a match

applyCachePreventionHeaders

protected void applyCachePreventionHeaders(javax.servlet.http.HttpServletResponse response)

Setting cache prevention headers to responses.

Parameters:

response - HTTP Servlet Response

doFilter

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

Specified by:

doFilter in interface javax.servlet.Filter

Throws:

IOException

javax.servlet.ServletException

destroy

public void destroy()

Specified by:

destroy in interface javax.servlet.Filter