See the filter javadocs.
Here's an example
<appender name="console" class="org.apache.log4j.ConsoleAppender">
<layout class="org.apache.log4j.SimpleLayout"/>
<filter class="org.apache.log4j.varia.ExpressionFilter">
<param name="Expression" value="logger == p1 && NDC.userid ==
u23" />
<param name="AcceptOnMatch" value="true"/>
<param name="ConvertInFixToPostFix" value="true"/>
</filter>
<filter class="org.apache.log4j.varia.DenyAllFilter"/>
</appender>
Notice in appenderSkeleton's doAppend method, filters are processed in
order.
http://cvs.apache.org/viewcvs.cgi/jakarta-log4j/src/java/org/apache/log4
j/AppenderSkeleton.java?rev=1.26&view=auto
Scott
-----Original Message-----
From: F Kurzawa [mailto:[EMAIL PROTECTED]
Sent: Tuesday, July 27, 2004 11:47 AM
To: Log4J Users List
Subject: RE: Decorating output before RollingFileAppender
This looks interesting and leaning towards what would suit me.
Forgive my ignorance, but I haven't seen any examples of how to use a
filter in a configuration file. Can you point me to some examples?
Thanks,
Frank
--- Scott Deboy <[EMAIL PROTECTED]> wrote:
> I have written a couple of filters that 'decorate' logging events -
> that may be a better route to go. See PropertyFilter and
> ReflectionFilter
> here:
>
http://cvs.apache.org/viewcvs.cgi/jakarta-log4j/src/java/org/apache/log4
> j/varia/
>
> In particular, ReflectionFilter sets the 'renderedMessage' on the
> event, which would probably be what you want to do. You may want to
> consider relying on the Expression mechanism (see ExpressionFilter in
> the same
> package) as a flexible way to determine which events have the filter
> applied.
>
> I haven't worked much with PaternLayout so I'm not sure how you would
> use it in a filter.
>
> Scott
>
> -----Original Message-----
> From: F Kurzawa [mailto:[EMAIL PROTECTED]
> Sent: Tuesday, July 27, 2004 10:37 AM
> To: Log4J Users List
> Subject: RE: Decorating output before RollingFileAppender
>
>
> Hi Yoav,
>
> I might be able to do what I want by extending RollingFileAppender,
> but a simpler solution for me would probably be to extend
> AsyncAppender to accept a PatternLayout parameter and then apply it
> before outputting to the next appender.
>
> Regardless, I was really hoping for a solution that would not require
> extending log4j. I was hoping there was a way to decorate log entries
> "inline" by passing them through some sort of filter, much the way
> that AsyncAppender acts as a filter of sorts in front of another
> appender.
>
> Regards,
>
> Frank
>
>
> --- "Shapira, Yoav" <[EMAIL PROTECTED]> wrote:
>
> >
> > Hi,
> > You can always extend either RollingFileAppender or PatternLayout to
> > suit your own needs. That's a big plus of open-source and our ASF
> > license ;)
> >
> > Yoav Shapira
> > Millennium Research Informatics
> >
> >
> > >-----Original Message-----
> > >From: F Kurzawa [mailto:[EMAIL PROTECTED]
> > >Sent: Tuesday, July 27, 2004 12:37 PM
> > >To: Log4J Users List
> > >Subject: RE: Decorating output before RollingFileAppender
> > >
> > >Hi James,
> > >
> > >Sorry I wasn't clearer.
> > >
> > >I need to be able to decorate the output BEFORE
> > >RollingFileAppender.
> > This
> > >is
> > >because I need to have different lines laid out out differently
> > depending
> > >on
> > >which logger that they came from. I don't have enough control with
> > >the single PatternLayout within RFA to get the different formatting
> > >that I need.
> > >
> > >The intuitively obvious approach was to use multiple
> > RollingFileAppenders,
> > >each
> > >of which would write to the same file. But RollingFileAppender
> > >becomes
> > very
> > >confused if other RFA's are writing to the same file, and the file
> > starts
> > >getting rotated willy-nilly as each RFA steps on the other.
> > >
> > >So that approach won't work.
> > >
> > >Regards,
> > >
> > >Frank
> > >
> > >--- James Stauffer <[EMAIL PROTECTED]> wrote:
> > >
> > >> RollingFileAppender extends FileAppender so it takes a
> > >> PatternLayout
> > >also.
> > >>
> > >> James Stauffer
> > >>
> > >>
> > >> -----Original Message-----
> > >> From: F Kurzawa [mailto:[EMAIL PROTECTED]
> > >> Sent: Tuesday, July 27, 2004 10:55 AM
> > >> To: Log4J Users List
> > >> Subject: Decorating output before RollingFileAppender
> > >>
> > >>
> > >> I want to format and modify my log4j output prior to sending to a
> > >> RollingFileAppender.
> > >>
> > >> If there were functionality that would allow me to easily apply a
> > >> PatternLayout prior to sending to a RollingFileAppender that
would
> > >> be
> > >ideal.
> > >>
> > >> I can insert an AsyncAppender before my RollingFileAppender, but
> > >> AsyncAppender does not take a PatternLayout parameter so it
doesn't
> > help.
> > >>
> > >> In fact, the only two appenders that take PatternLayout arguments
> > >> are
> > the
> > >> *FileAppender's and ConsoleAppender.
> > >>
> > >> Is there a simple way to decorate my output with a PatternLayout
> > >> (or
> > some
> > >> similar functionality) prior to its arrival in a
> > >> RollingFileAppender?
> > >>
> > >> Thanks in advance,
> > >>
> > >> Frank
> > >>
>
>
> =====
> Frank Kurzawa
> Topaz Software
> [EMAIL PROTECTED]
>
>
>
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=====
Frank Kurzawa
Topaz Software
[EMAIL PROTECTED]
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