logging-log4j-user mailing list archives

Site index · List index
Message view « Date » · « Thread »
Top « Date » · « Thread »
From Bender Heri <hben...@ergonomics.ch>
Subject AW: Problems with inheritance of com.foo... loggers
Date Thu, 04 Feb 2010 15:48:53 GMT
There is one point more: You do not define a root logger in your config which has some benefits
The root is the parent for all loggers which are not explicitely defined (e.g. also for third
party libraries like org.apache....).
Typically you set the root logger level to WARN. And for the package/classes which you want
to examine deeper you define a extra logger with desired lower level.
If you want to have a lot of logger configurations which differ only in level setting but
have all the same appender, then you define the appender only once in the root logger. 
Only if you explicitely want to have one distinct logger to log to another appender you define
it in the respective logger definition and set the attribute additivity="false" (default is
true).
Heri 

-----Urspr√ľngliche Nachricht-----
Von: Jens Gruentjes [mailto:jens.gruentjes@ebira.de] 
Gesendet: Donnerstag, 4. Februar 2010 15:36
An: log4j-user@logging.apache.org
Betreff: Re: Problems with inheritance of com.foo... loggers

Hi Douglas,

thanks for your answer which helped me save a lot of time. Your explanation is evident but
I did not realize that for myself.
--
Kind regards
Jens


Zitat von "Douglas E Wegscheid" <Douglas_E_Wegscheid@whirlpool.com>:

> "de.wota.segmentation.Bar" will inherit from "de.wota.segmentation", 
> "de.wota", and "de" but not "de.wota.MyApp".
>
> Change your configuration to set up logging for "de.wota" instead of 
> "de.wota.MyApp".
>
> Douglas E Wegscheid
> Lead Technical Analyst, Whirlpool Corporation
> (269)-923-5278
>
> "A wrong note played hesitatingly is a wrong note. A wrong note played 
> with conviction is interpretation."
>
>
>
> "Jens Gruentjes" <jens.gruentjes@ebira.de> wrote on 02/04/2010 
> 02:57:10
> AM:
>
>> Hello to all readers,
>>
>> I am new to log4j and I encounter several problems which are maybe 
>> caused by my limited understanding fo log4j.
>>
>> I have a simple setup with two classes (de.wota.MyApp and
>> de.wota.segmentation.Bar) and an xml configuration file for log4j. I 
>> thought that the logger defined in Bar.java inherits its level and 
>> most of all its appender(s) from the logger defined in MyApp.java. 
>> But despite reading the manuals and the list archives I always get 
>> the following error when I execute MyApp:
>>
>> jens@jensen ~/Java/wota_rw $ java de.wota.MyApp
>> log4j: reset attribute= "false".
>> log4j: Threshold ="null".
>> log4j: Retreiving an instance of org.apache.log4j.Logger.
>> log4j: Setting [de.wota.MyApp] additivity to [true].
>> log4j: Level value for de.wota.MyApp is  [DEBUG].
>> log4j: de.wota.MyApp level set to DEBUG
>> log4j: Class name: [org.apache.log4j.ConsoleAppender]
>> log4j: Setting property [target] to [System.out].
>> log4j: Setting property [threshold] to [INFO].
>> log4j: Parsing layout of class: "org.apache.log4j.PatternLayout"
>> log4j: Setting property [conversionPattern] to [%8r %p %c %x - %m%n].
>> log4j: Adding appender named [console] to category [de.wota.MyApp].
>>         0 INFO de.wota.MyApp  - Entering application.
>> log4j:WARN No appenders could be found for logger
> (de.wota.segmentation.Bar).
>> log4j:WARN Please initialize the log4j system properly.
>> Parent is root
>>         1 INFO de.wota.MyApp  - Exiting application.
>> jens@jensen ~/Java/wota_rw $
>>
>> What I expected to see was the output from Bar.java which is missing 
>> here. I wanted to know who is the parent of the logger in Bar.java is 
>> and it turned out to be root. I thought that this should be the 
>> logger from MyApp.java. Can someone tell me what I misunderstand? I 
>> am a little confused. The code follows below.
>>
>> Thanks for your explanations and your help!
>>
>>
>> This is MyApp.java:
>>
>> package de.wota;
>>
>> import org.apache.log4j.Logger;
>> import org.apache.log4j.xml.DOMConfigurator;
>>
>> import de.wota.segmentation.Bar;
>>
>> public class MyApp {
>>      // Define a static logger variable so that it references the
>>      // Logger instance named "MyApp".
>>      static Logger logger = Logger.getLogger(MyApp.class);
>>
>>      public static void main(String[] args) {
>>
>>          // Set up an xml configuration that logs on the console.
>>          DOMConfigurator.configureAndWatch("config_log.xml");
>>
>>          logger.info("Entering application.");
>>          Bar bar = new Bar();
>>          bar.doIt();
>>          logger.info("Exiting application.");
>>      }
>> }
>>
>> This is Bar.java:
>>
>> package de.wota.segmentation;
>>
>> import org.apache.log4j.Logger;
>>
>> public class Bar {
>>      static Logger logger = Logger.getLogger(Bar.class);
>>
>>      public void doIt() {
>>        logger.debug("Did it again!");
>>        System.out.println("Parent is "+logger.getParent().getName());
>>      }
>>
>> }
>>
>> And finally config_log.xml
>>
>> <?xml version="1.0" encoding="UTF-8" ?> <!DOCTYPE log4j:configuration 
>> SYSTEM "log4j.dtd">
>>
>> <log4j:configuration debug="true"
>> xmlns:log4j="http://jakarta.apache.org/log4j/">
>>
>>    <appender name="console" class="org.apache.log4j.ConsoleAppender">
>>      <param name="Target" value="System.out"/>
>>      <param name="threshold" value="info" />
>>      <layout class="org.apache.log4j.PatternLayout">
>>        <param name="ConversionPattern" value="%8r %p %c %x - %m%n"/>
>>      </layout>
>>    </appender>
>>
>>    <logger name="de.wota.MyApp">
>>      <level value="DEBUG" />
>>      <appender-ref ref="console" />
>>    </logger>
>>
>> </log4j:configuration>
>>
>> --
>> Kind regards
>> Jens
>>
>>
>>
>> ---------------------------------------------------------------------
>> To unsubscribe, e-mail: log4j-user-unsubscribe@logging.apache.org
>> For additional commands, e-mail: log4j-user-help@logging.apache.org
>>
>


---------------------------------------------------------------------
To unsubscribe, e-mail: log4j-user-unsubscribe@logging.apache.org
For additional commands, e-mail: log4j-user-help@logging.apache.org


---------------------------------------------------------------------
To unsubscribe, e-mail: log4j-user-unsubscribe@logging.apache.org
For additional commands, e-mail: log4j-user-help@logging.apache.org


Mime
View raw message