Thanks Bill This helps a lot. I'm using Log4j, so this is good news. Also, I wont be putting any of my classes in $CATALINA_HOME/shared/lib or $CATALINA_HOME/common/lib.
Thanks again. --- Bill Barker <[EMAIL PROTECTED]> wrote: > > "Mon Cab" <[EMAIL PROTECTED]> wrote in message > news:[EMAIL PROTECTED] > > > >> > >> Good day > >> > >> I am having a hard time understanding how to use commons logging > on > > Tomcat. The struts.apache.org suggest the following usage > (presumably > > for business objects) (taken from: > >> http://struts.apache.org/1.x/userGuide/building_controller.html ) > >> > >> > >> package com.foo; > >> // ... > >> import org.apache.commons.logging.Log; > >> import org.apache.commons.logging.LogFactory; > >> ... > >> public class User { > >> // ... > >> private static Log log = > >> LogFactory.getLog(User.class); > >> // ... > >> public void setBar(Bar bar) { > >> > >> log.trace("Setting bar to " + bar); > >> this.bar = bar; > >> } > >> // ... > >> } > >> > >> > >> The suggestion seems to be that it is OK to declare my Logger as a > >> static variable in the business object. This is ideal for me > >> because, > >> I will be accessing the Logger from both instance and static > methods, > >> and so I do not want to have to declare this as an instance > variable. > >> > >> > >> However, I am wondering whether this is OK, given that my business > >> objects will be being accessed from different servlet threads. > Can > >> anyone tell me whether this is OK?, and if not, what is the > correct > >> way > >> to do this? > >> > > I think that there may be a race condition with SimpleLog. But JULI > and > Log4j are thread-safe, so it's fine to use a static instance of Log > with > these. > > >> My second question is whether the same usage is valid for Action > (or > > servlet) classes. I saw the following example, at > >> > > > http://www.mobilefish.com/developer/struts/struts_quickguide_log4j.html > >> but am not certain as to whether using a static variable would be > OK > >> here. Would it? > >> > >> public class DemoServlet extends Servlet { > >> > >> private static Log log = > >> LogFactory.getLog("com.mobilefish.DemoAction"); > >> > >> public service etc etc {} > > > >> } > >> > >> The commons logging documentation notes the following: > >> > >> Note that for application code, declaring the log member as > "static" > >> is > >> more efficient as one Log object is created per class, and is > >> recommended. However this is not safe to do for a class which may > be > >> deployed via a "shared" classloader in a servlet or j2ee container > or > >> similar environment. If the class may end up invoked with > different > >> thread-context-classloader values set then the member must not be > >> declared static. The use of "static" should therefore be avoided > in > >> code within any "library" type project. > >> > >> I'm not clear as to what the above means, from a practical > >> perspective > >> in the context of a web applicaiton. What does this mean in > simple > >> terms? > >> > > It means that you have potential gotus if you use a static instance > in a > class that is in a jar in $CATALINA_HOME/shared/lib or > $CATALINA_HOME/common/lib. It's fine to use a static instance if the > class > is living in a jar in WEB-INF/lib. > > >> Taken from: > >> > > > http://jakarta.apache.org/commons/logging/guide.html#Configuring_Log4J > >> > >> > >> > >> > >> > >> > >> > > > ____________________________________________________________________________________ > >> The all-new Yahoo! Mail beta > >> Fire up a more powerful email and get things done faster. > >> http://new.mail.yahoo.com > >> > >> > > > > > > > > > > > ____________________________________________________________________________________ > > Sponsored Link > > > > $420k for $1,399/mo. > > Think You Pay Too Much For Your Mortgage? > > Find Out! www.LowerMyBills.com/lre > > > > > --------------------------------------------------------------------- > > To start a new topic, e-mail: users@tomcat.apache.org > > To unsubscribe, e-mail: [EMAIL PROTECTED] > > For additional commands, e-mail: [EMAIL PROTECTED] > > > > > > > > > --------------------------------------------------------------------- > To start a new topic, e-mail: users@tomcat.apache.org > To unsubscribe, e-mail: [EMAIL PROTECTED] > For additional commands, e-mail: [EMAIL PROTECTED] > > ____________________________________________________________________________________ Sponsored Link Mortgage rates near 39yr lows. $510k for $1,698/mo. Calculate new payment! www.LowerMyBills.com/lre --------------------------------------------------------------------- To start a new topic, e-mail: users@tomcat.apache.org To unsubscribe, e-mail: [EMAIL PROTECTED] For additional commands, e-mail: [EMAIL PROTECTED]
