Hi Naresh,
No, I mean one repository selector per JVM. Actually, this is sort of per ClassLoader if you look at the case of webapps where the classloading behavior is different than normal. Webapps load classes, preferentially, from the WebappClassLoader before looking to its parent classloader(s) so if Log4j is stored in WEB-INF/lib of each app, Log4j has multiple unique logging environments in a single JVM. However, if normal classloading behavior is assumed, then it is once per JVM. Either way, Log4j can have only one selector at a time in any single unique logging environment.
It is the repository selector that maintains the separation of repositories. Any individual repository selector must override the getLoggerRepository() method. Log4j will call that method to get the logger repository for an application. If the selector is being smart and storing some information which identifies certain applications, it can return a unique logger repository per application. That is what the ContextClassLoaderSelector does. It stores a map of logger repositories and keys each logger repository by the context classloader (the WebappClassLoader unique to each webapp). So when Log4j asks for the logger repository in order to log for the app, the selector will only return the logger repository keyed for that application.
Make sure you don't confuse the LoggerRepositorySelector with the LoggerRepository. Only one of the former can be set at any one time (which we guard). There can be infinite of the latter.
Does that make more sense?
Jake
At 08:13 PM 2/25/2003 -0800, you wrote:
Hi Jacob,
Iam attempting to incorporate similar custom repository selector approach. You mentioned "Note that Log4j will only use *ONE* custom repository selector."
Did u mean one custom repository selector per app?
If the answer is Yes, than my confusion is, Since LogManager has one private member variable of type repository selector and we initialize that to a custom repository by following Object guard = new Object(); LogManager.setRepositorySelector(new CusRepository(contextName), guard);
and if log4j is loaded only one time by the parent classloader, how does logmanager maintain reference of every application's CusRepositry ?
--- Jacob Kjome <[EMAIL PROTECTED]> wrote: > Hello James, > > The functionality you are looking for is to be able > to log within > unique logger repositories using a custom logger > repository selector. > I have implemented such a selector (and a servlet > context listener > which configures log4j to use it at app/server > startup) which keys > logger repositories on the current classloader. > Ceki has written > about a repository selector which would use JNDI to > key logger > repositories. > > Now, since you are using JBoss and they have their > single classloader > concept (which, admittedly, I'm not so familiar > with) I'm not sure the > repository selector that I wrote will work for you. > It certainly > works in an environment where each webapp has its > own unique > classloader. This still might be true for JBoss, > but I'm not > positive. > > To check out the repository selector I wrote, look > here: > http://cvs.apache.org/viewcvs/jakarta-log4j-sandbox/src/java/org/apache/log4j/selector/ContextClassLoaderSelector.java?rev=1.3&content-type=text/vnd.viewcvs-markup > > See the servlet context listener which initializes > Log4j to use this > custom selector here: > http://cvs.apache.org/viewcvs/jakarta-log4j-sandbox/src/java/org/apache/log4j/servlet/InitContextListener.java?rev=1.2&content-type=text/vnd.viewcvs-markup > > Note that Log4j will only use *ONE* custom > repository selector. Once > one is installed, the only way to change it to > re-install the selector > along with the original guard object which is used > to protect the > selector from being changed by a process not meant > to do so. So, > unless you store the guard, you can pretty much > assume that this is a > one-shot thing. As such, ideally, the container > should be responsible > for installing the selector. My servlet context > listener allows for > any particular webapp to install the selector if one > isn't already > installed. If one is, the installation will fail > and the exception > hidden. In this situation, it is assumed that > whatever process did > the install knew what it was doing and the app will > just have to live > with the decision. > > > For sure, read Ceki's article about custom selectors > and pay attention > to the JNDI selector discussion: > http://qos.ch/logging/sc.html > > > Note, if you implement a JNDI selector that works > for you, it would be > great if you could contribute that back to the > Log4j-sandbox project! > > > Jake > > Tuesday, February 25, 2003, 1:48:51 PM, you wrote: > > CJ> An answer to this question/problem is very > important to my project group so > CJ> please take time to read and understand it. > Thanks. I struggled with > CJ> posting this to a JBOSS group but decided it was > more of an issue with the > CJ> use of Log4J and not so much how JBOSS was using > it. > > > > CJ> I am using JBOSS and am attempting to define > application independent logging > CJ> using Log4J. > > CJ> JBOSS uses Log4J for their logging as well, > which is where my problems > CJ> begin. > > > > CJ> If I use the PropertyConfigurator to configure > log4J using an application > CJ> specific config file. Its settings conflict > with the JBOSS logging. My > CJ> first attempt was defining the root and file > appenders for the root logger > CJ> which is probably what was throwing the Log4J > logging into a loop. > > > > CJ> My solution was to define a category and log to > that vs. getting the logger > CJ> and logging to it. > > > > CJ> The results were encouraging but problematic as > well. My error, debug, info > CJ> messages are showing up in the JBOSS console log > just fine, but are appended > CJ> to an [INFO] message from the JBOSS (log4j) > logging. So it appears that > CJ> every message logged to my category is getting > appended to a JBOSS log > CJ> message (in this case INFO priority) before > being logged to the console or > CJ> file. > > > > CJ> How can I define my application specific logging > so it can coexist with the > CJ> logging configuration defined by the app server > which uses log4J but be > CJ> independent. I do not want to have to modify > the log4J configuration that > CJ> is setup by the JBOSS server implementation. I > want to be able to configure > CJ> my own configuration file, load it with a > console and file appenders that > CJ> coexist with the ones in the JBOSS specific > log4J configuration but do not > CJ> conflict with the root ones defined. HOW????? > > > > CJ> Below is a snapshot of my application log4j > configuration file that I am > CJ> loading. The JBOSS log4j configuration appears > to define a console and file > CJ> appender for the root logger. This > configuration works with the caveat that > CJ> any logging to this category gets appended to > the JBOSS log text before > CJ> being displayed to the console or log file. > > > > CJ> ## The server.log file appender for LightSpeed > > CJ> log4j.category.LightSpeed=, LightSpeed_Console, > LightSpeed_Default > > CJ> > log4j.appender.LightSpeed_Default=org.apache.log4j.RollingFileAppender > > CJ> > log4j.appender.LightSpeed_Default.File=server.log > > CJ> > log4j.appender.LightSpeed_Default.MaxFileSize=500KB > > CJ> > log4j.appender.LightSpeed_Default.MaxBackupIndex=1 > > CJ> > log4j.appender.LightSpeed_Default.layout=org.apache.log4j.PatternLayout > > CJ> > #log4j.appender.LightSpeed_Default.layout.ConversionPattern=%d > %-5p [%t] > CJ> %-17c{2} (%13F:%L) %3x - %m\n > > CJ> > #log4j.appender.LightSpeed_Default.layout.ConversionPattern=[%d{ABSOLUTE},%c > CJ> {1}] %m%n > > CJ> > log4j.appender.LightSpeed_Default.layout.ConversionPattern=%d{ABSOLUTE},%-17 > CJ> c [%-5p] - %m%n > > > > CJ> #log4j.additivity.LightSpeed=false > > > > CJ> > log4j.appender.LightSpeed_Console=org.apache.log4j.ConsoleAppender > > CJ> > log4j.appender.LightSpeed_Console.layout=org.apache.log4j.PatternLayout > === message truncated ===
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