org.mortbay.servlet
Class UserAgentFilter

java.lang.Object
  org.mortbay.servlet.UserAgentFilter

All Implemented Interfaces:

Filter

Direct Known Subclasses:

GzipFilter

public class UserAgentFilter
extends Object
implements Filter

User Agent Filter.

This filter allows efficient matching of user agent strings for downstream or extended filters to use for browser specific logic.

The filter is configured with the following init parameters:

attribute

If set, then the request attribute of this name is set with the matched user agent string

cacheSize

The size of the user-agent cache, used to avoid reparsing of user agent strings. The entire cache is flushed when this size is reached

userAgent

A regex Pattern to extract the essential elements of the user agent. The concatenation of matched pattern groups is used as the user agent name

An example value for pattern is (?:Mozilla[^\(]*\(compatible;\s*+([^;]*);.*)|(?:.*?([^\s]+/[^\s]+).*). These two pattern match the common compatibility user-agent strings and extract the real user agent, failing that, the first element of the agent string is returned.

Author:

gregw

Constructor Summary

UserAgentFilter()

Method Summary

void	destroy()
void	doFilter(ServletRequest request, ServletResponse response, FilterChain chain)
String	getUserAgent(ServletRequest request)
String	getUserAgent(String ua) Get UserAgent.
void	init(FilterConfig filterConfig)

Methods inherited from class java.lang.Object

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

Constructor Detail

UserAgentFilter

public UserAgentFilter()

Method Detail

destroy

public void destroy()

Specified by:

destroy in interface Filter

doFilter

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

Specified by:

doFilter in interface Filter

Throws:

IOException

ServletException

init

public void init(FilterConfig filterConfig)
          throws ServletException

Specified by:

init in interface Filter

Throws:

ServletException

getUserAgent

public String getUserAgent(ServletRequest request)

getUserAgent

public String getUserAgent(String ua)

Get UserAgent. The configured agent patterns are used to match against the passed user agent string. If any patterns match, the concatenation of pattern groups is returned as the user agent string. Match results are cached.

Parameters:

ua - A user agent string

Returns:

The matched pattern groups or the original user agent string