com.sun.appserv.web.cache.filter

Class CachingFilter

java.lang.Object

com.sun.appserv.web.cache.filter.CachingFilter

All Implemented Interfaces:

CacheManagerListener, javax.servlet.Filter

public class CachingFilter
extends Object
implements javax.servlet.Filter, CacheManagerListener

Constructor Summary

Constructors

Constructor and Description
CachingFilter()

Method Summary

Modifier and Type	Method and Description
void	cacheManagerDisabled() cache manager listener method
void	cacheManagerEnabled() cache manager listener method
void	destroy() Called by the web container to indicate to a filter that it is being taken out of service.
void	doFilter(javax.servlet.ServletRequest srequest, javax.servlet.ServletResponse sresponse, 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.
void	init(javax.servlet.FilterConfig filterConfig) Called by the web container to indicate to a filter that it is being placed into service.

Methods inherited from class java.lang.Object

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

Constructor Detail

CachingFilter

public CachingFilter()

Method Detail

init

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

Called by the web container to indicate to a filter that it is being placed into service. The servlet container calls the init method exactly once after instantiating the filter. The init method must complete successfully before the filter is asked to do any filtering work.

Specified by:

init in interface javax.servlet.Filter

Parameters:

filterConfig - filter config

Throws:

javax.servlet.ServletException

doFilter

public void doFilter(javax.servlet.ServletRequest srequest,
                     javax.servlet.ServletResponse sresponse,
                     javax.servlet.FilterChain chain)
              throws 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 in to this method allows the Filter to pass on the request and response to the next entity in the chain.

Specified by:

doFilter in interface javax.servlet.Filter

Parameters:

srequest - the runtime request

sresponse - the runtime response

chain - the filter chain to in the request processing

Throws:

IOException, - ServletException - First check if this HTTP method permits caching (using helper) if not, call the downstream filter and return. - Otherwise, get the key based on the request (using helper). - Check if we have a response entry in the cache already. - If there is entry and is valid, write out the response from that entry. - create a CachingResponse and CachingOutputStream wrappers and call the downstream filter

IOException

javax.servlet.ServletException

cacheManagerEnabled

public void cacheManagerEnabled()

cache manager listener method

Specified by:

cacheManagerEnabled in interface CacheManagerListener

cacheManagerDisabled

public void cacheManagerDisabled()

cache manager listener method

Specified by:

cacheManagerDisabled in interface CacheManagerListener

destroy

public void destroy()

Called by the web container to indicate to a filter that it is being taken out of service. This method is only called once all threads within the filter's doFilter method have exited or after a timeout period has passed. After the web container calls this method, it will not call the doFilter method again on this instance of the filter.

Specified by:

destroy in interface javax.servlet.Filter