org.mortbay.servlet
Class GzipFilter

java.lang.Object
  extended by org.mortbay.servlet.UserAgentFilter
      extended by 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:

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

Nested Class Summary
 class GzipFilter.GZIPResponseWrapper
           
static class GzipFilter.GzipStream
           
 
Field Summary
protected  int _bufferSize
           
protected  java.util.Set _excluded
           
protected  java.util.Set _mimeTypes
           
protected  int _minGzipSize
           
 
Constructor Summary
GzipFilter()
           
 
Method Summary
 void destroy()
          Called by the web container to indicate to a filter that it is being taken out of service.
 void doFilter(ServletRequest req, ServletResponse res, 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(FilterConfig filterConfig)
          Called by the web container to indicate to a filter that it is being placed into service.
protected  GzipFilter.GZIPResponseWrapper newGZIPResponseWrapper(HttpServletRequest request, HttpServletResponse response)
           
 
Methods inherited from class org.mortbay.servlet.UserAgentFilter
getUserAgent, getUserAgent
 
Methods inherited from class java.lang.Object
clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait
 

Field Detail

_mimeTypes

protected java.util.Set _mimeTypes

_bufferSize

protected int _bufferSize

_minGzipSize

protected int _minGzipSize

_excluded

protected java.util.Set _excluded
Constructor Detail

GzipFilter

public GzipFilter()
Method Detail

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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