Eric,
By "clientNumber" I take that you are referring to one of your specific keys
that you have inserted into the MDC? So, the bug is that if I use the %X
pattern without a specified key, log4j "blows up"? But, %X{<your key here>}
works just fine?
Can you please enter a bug for the behavior you are seeing, with as much
detail as you can provide (examples, code, stack traces, etc)? You can find
the bug database at
http://nagoya.apache.org/bugzilla/
thanks,
-Mark
> -----Original Message-----
> From: E Thors [mailto:[EMAIL PROTECTED]]
> Sent: Wednesday, July 03, 2002 9:28 AM
> To: [EMAIL PROTECTED]
> Subject: bug with MDC with patch
>
>
> I believe I have done my due diligence on this one.
> There seems to be a problem with MDC, when you specify
> the pattern %X without a clientNumber. The problem is
> that the current code does not handle it gracefully.
> It throws an exception and blows up the application.
> Could not find anything in bug tracking. Tried to
> check cvs, but currently seems to be down. I realize
> that you should specify the clientNumber. An error in
> the log4j properites file should not kill the
> application. Below I have included a small program and
> log4j.properties file.
>
> I am wondering if someone could explain the pros and
> cons of NDC and MDC. I have gone through the archives
> of log4j-user. It seems like the general feeling was
> that MDC is better. I want to be able to track a
> user's session through the web site. So when I hit the
> jsp page, I would call MDC.put or NDC.push the session
> id. Anything called from the jsp page could be trace
> by the session id. My initial unscientific experience
> with NDC was that at times the stack seemed to retain
> items.
>
> On a related note concerning the usage of the pattern
> %X{clientNumber}for MDC seems like it would be nice if
> %X without a clientNumber would print out the entire
> Hashtable. This would allow the person debugging an
> application that did not have access to the
> documentation or source code an easy way to find out
> what all of the current context were at that point.
> They then could possibly refine the pattern they would
> use.
>
> I have gone on too long now. Hopefully someone will
> read it.
>
> Thanks,
>
> eric
>
>
> OS: Win2000
> Java:1.3.1
> Log4j: 1.2.4
>
> ---- TestError.java----------
> public class TestError {
> static Logger log = Logger.getLogger("foo");
>
> public static void main (String[] args) {
> PropertyConfigurator.configure(args[0]);
>
> System.out.println("start");
> MDC.put("test", "foo");
> log.warn("Warn me");
> log.error("Warn me");
> System.out.println("done");
>
> }
> }
> -------------------
> ------ log4j.properties --------------
> log4j.rootCategory=warn, A2, RR, dest2
>
> # A2 is set to be a LF5Appender
> log4j.appender.A2=org.apache.log4j.lf5.LF5Appender
> log4j.appender.A2.layout=org.apache.log4j.PatternLayout
> log4j.appender.A2.layout.ConversionPattern=[slf5s.start]%d{DAT
> E}[slf5s.DATE]%n\
>
> %p[slf5s.PRIORITY]%n%x[slf5s.NDC]%n%t[slf5s.THREAD]%n\
>
> %c[slf5s.CATEGORY]%n%l[slf5s.LOCATION]%n%m[slf5s.MESSAGE]%n%n
>
> log4j.appender.dest2.ImmediateFlush=true
> log4j.appender.dest2.layout=org.apache.log4j.PatternLayout
> log4j.appender.dest2.layout.ConversionPattern=%-4r
> [%t] %-5p %c (%X) - %m ~%l%n
>
> ! WRITE LOG TO A FILE, ROLL THE FILE AFTER SOME SIZE
> log4j.appender.dest2=org.apache.log4j.DailyRollingFileAppender
> ! This appender will only log messages with priority
> equal to or higher than
> ! the one specified here
> log4j.appender.dest2.Threshold=WARN
> ! Specify the file name (${property_key} gets
> substituted with its value)
> log4j.appender.dest2.File=log4j.log
>
> # RR is the RollingFileAppender that outputs to a
> rolling log
> # file called sample.log.
>
> log4j.appender.RR=org.apache.log4j.RollingFileAppender
> log4j.appender.RR.File=sample.log
>
> log4j.appender.RR.layout=org.apache.log4j.PatternLayout
> log4j.appender.RR.layout.ConversionPattern=[slf5s.start]%d{DAT
> E}[slf5s.DATE]%n\
>
> %p[slf5s.PRIORITY]%n%x[slf5s.NDC]%n%t[slf5s.THREAD]%n\
>
> %c[slf5s.CATEGORY]%n%l[slf5s.LOCATION]%n%m[slf5s.MESSAGE]%n%n
>
> # Set the max size of the file
> log4j.appender.RR.MaxFileSize=500KB
> ------------------------
>
> -------Error ----------------
>
> java TestError log4j.properties
> start
> java.lang.NullPointerException
> at java.util.Hashtable.get(Hashtable.java:320)
> at org.apache.log4j.MDC.get0(MDC.java:121)
> at org.apache.log4j.MDC.get(MDC.java:75)
> at
> org.apache.log4j.spi.LoggingEvent.getMDC(LoggingEvent.java:228)
> at
> org.apache.log4j.helpers.PatternParser$MDCPatternConverter.con
> vert(PatternParser.java:455)
> at
> org.apache.log4j.helpers.PatternConverter.format(PatternConver
> ter.java:56)
> at
> org.apache.log4j.PatternLayout.format(PatternLayout.java:495)
> at
> org.apache.log4j.WriterAppender.subAppend(WriterAppender.java:292)
> at
> org.apache.log4j.RollingFileAppender.subAppend(RollingFileAppe
> nder.java:225)
> at
> org.apache.log4j.WriterAppender.append(WriterAppender.java:150)
> at
> org.apache.log4j.AppenderSkeleton.doAppend(AppenderSkeleton.java:221)
> at
> org.apache.log4j.helpers.AppenderAttachableImpl.appendLoopOnAp
> penders(AppenderAttachableImpl.java:57)
> at
> org.apache.log4j.Category.callAppenders(Category.java:190)
> at
> org.apache.log4j.Category.forcedLog(Category.java:375)
> at
> org.apache.log4j.Category.warn(Category.java:1024)
> at TestError.main(TestError.java:11)
>
> If it were to exit gracefully, you should see "done".
>
> ----- Patch -------------
> --- MDC.java 2002-07-03 12:09:01.000000000 -0400
> +++ c:/MDC.java 2002-07-03 08:40:54.000000000 -0400
> @@ -117,7 +117,7 @@
> return null;
> } else {
> Hashtable ht = (Hashtable)
> ((ThreadLocalMap)tlm).get();
> - if(ht != null) {
> + if(ht != null && key != null) {
> return ht.get(key);
> } else {
> return null;
>
>
>
> __________________________________________________
> Do You Yahoo!?
> Sign up for SBC Yahoo! Dial - First Month Free
> http://sbc.yahoo.com
>
> --
> To unsubscribe, e-mail:
> <mailto:[EMAIL PROTECTED]>
> For additional commands, e-mail:
> <mailto:[EMAIL PROTECTED]>
>
--
To unsubscribe, e-mail: <mailto:[EMAIL PROTECTED]>
For additional commands, e-mail: <mailto:[EMAIL PROTECTED]>
