Suggesting minor change

[David Sklarew <da...@yahoo.com>]

Hi,
  I am suggesting a very minor change to
PropertyConfigurator and Category to simplify
customizing log4J.  The new ability to plugin in your
own Configurator is great.  I know I could extend
PropertyConfigurator and tell log4j to use my class as
the Configurator, but this change seems like a good
design decision.

Suggestion:

Since there is really strong coupling between the
Category and Priority sublcasses, PropertyConfigurator
should not call Priority.toPriority(priorityString)
but instead should call the following new method in
Category:

   /*** Set Priority based on string priority
representation */
   public void setPriorityString priorityStr) {
     setPriority(MyPriority.toPriority(priorityStr));
   }

Reasoning:
Category has methods insolating users of log4J from
having to know anything about the Priority class.  Why
should the configuration interface to log4J have to
know how who is resonsible for creating a Priority
from a string representation?


Background:
   When extending log4J, the PropertyConfigurator must
be subclasses or replaced by a new Configurator to
enable property file based configuration of categories
using a custom Priority(ie. TRACE).

Otherwise, the following line in the property config
file will not work:
log4j.rootCategory=TRACE, A1

This is because ProperConfigurator calls method
parseCategory which calls
Priority.toPriority(priorityStr).  This method knows
nothing about the added priority level(s).

Reasoning for change:

If a developer wants to add a custom Priority, he must
do the following

1) Subclass Priority (ie MyPriority) overriding
toPriority methods
2) Create CategoryFactory, adding
isCustomPriorityEnabled() method
3) Implement a CategoryFactory that instantiates
MyCategory instances
4) Modify PropertyConfigurator (or Priority class) so
that configured categories can be set to new priority
level via config file.

---
Step 4 seems unwarranted.  It does not seem like it
should be the configurators responsibility to know how
to convert a string to a Priority ( or if it should,
it could do so using calling methods on a Priority
instance which could be set as an instance of a custom
priority class.  


Comments appreciated

David Sklarew
david_sklarew@yahoo.com



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