org.mortbay.servlet
Class GzipFilter
java.lang.Object
org.mortbay.servlet.UserAgentFilter
org.mortbay.servlet.GzipFilter
- All Implemented Interfaces:
- Filter
- Direct Known Subclasses:
- IncludableGzipFilter
public class GzipFilter
- extends UserAgentFilter
GZIP Filter
This filter will gzip the content of a response iff:
- The filter is mapped to a matching path
- The response status code is >=200 and <300
- The content length is unknown or more than the
minGzipSize
initParameter or the minGzipSize is 0(default)
- The content-type is in the coma separated list of mimeTypes set in the
mimeTypes
initParameter or
if no mimeTypes are defined the content-type is not "application/gzip"
- No content-encoding is specified by the resource
Compressing the content can greatly improve the network bandwidth usage, but at a cost of memory and
CPU cycles. If this filter is mapped for static content, then use of efficient direct NIO may be
prevented, thus use of the gzip mechanism of the DefaultServlet
is
advised instead.
This filter extends UserAgentFilter
and if the the initParameter excludedAgents
is set to a comma separated list of user agents, then these agents will be excluded from gzip content.
- Author:
- gregw
Methods inherited from class java.lang.Object |
clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait |
_mimeTypes
protected java.util.Set _mimeTypes
_bufferSize
protected int _bufferSize
_minGzipSize
protected int _minGzipSize
_excluded
protected java.util.Set _excluded
GzipFilter
public GzipFilter()
init
public void init(FilterConfig filterConfig)
throws ServletException
- Description copied from interface:
Filter
- 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.
The web container cannot place the filter into service if the init method either
1.Throws a ServletException
2.Does not return within a time period defined by the web container
- Specified by:
init
in interface Filter
- Overrides:
init
in class UserAgentFilter
- Throws:
ServletException
destroy
public void destroy()
- Description copied from interface:
Filter
- 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.
This method gives the filter an opportunity to clean up any resources that are being held (for
example, memory, file handles, threads) and make sure that any persistent state is synchronized
with the filter's current state in memory.
- Specified by:
destroy
in interface Filter
- Overrides:
destroy
in class UserAgentFilter
doFilter
public void doFilter(ServletRequest req,
ServletResponse res,
FilterChain chain)
throws java.io.IOException,
ServletException
- Description copied from interface:
Filter
- 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.
A typical implementation of this method would follow the following pattern:-
1. Examine the request
2. Optionally wrap the request object with a custom implementation to
filter content or headers for input filtering
3. Optionally wrap the response object with a custom implementation to
filter content or headers for output filtering
4. a) Either invoke the next entity in the chain using the FilterChain object (chain.doFilter()
),
4. b) or not pass on the request/response pair to the next entity in the filter chain to block the request processing
5. Directly set headers on the response after invocation of the next entity in the filter chain.
- Specified by:
doFilter
in interface Filter
- Overrides:
doFilter
in class UserAgentFilter
- Throws:
java.io.IOException
ServletException
newGZIPResponseWrapper
protected GzipFilter.GZIPResponseWrapper newGZIPResponseWrapper(HttpServletRequest request,
HttpServletResponse response)
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