Improvements to the new LogFactory APIs, based on feedback from Costin and

Jon plus some additional thought about using it in a multi-class-loader
environment (like Tomcat):

* Changed newFactory() to getFactory(), and implemented a cache of
  previously created factory instances (one per class loader).  This
  avoids potentially expensive and redundant discovery operations.

* Added convenient static getLog() method so a typical application
  component can initialize it's Log instance like this:

    Log log = LogFactory.getLog("com.mycompany.mypackage.MyClass");

* Added variants of getInstance() and getLog() that take a Class
  parameter instead of a String.  LogSource had this convenience
  feature, and there's no reason not to keep it.

* Added release() and releaseAll() methods to instruct the factory
  instances to release any cached references to other LogFactory
  or Log instances.  This is important, for example, if you put
  commons-logging.jar in Tomcat's shared "lib" directory, and then
  use the application reload facility.  The references maintained
  here would otherwise prevent garbage collection of the old
  webapp class loader once a reload takes place.

* Added a note on getInstance() that you can make no assumptions
  about whether or not the actual Log instance you get back is
  shared or not.  The actual sharability is a feature of the
  LogFactory implementation you are using, and what kind of a
  class loader environment you ae installing.

* Deprecated LogSource, but left it there to ease transition of
  existing code using it.


git-svn-id: https://svn.apache.org/repos/asf/jakarta/commons/proper/logging/trunk@138858 13f79535-47bb-0310-9956-ffa450edef68

src/java/org/apache/commons/logging/LogSource.java

@@ -1,7 +1,7 @@
 /*
- * $Header: /home/jerenkrantz/tmp/commons/commons-convert/cvs/home/cvs/jakarta-commons//logging/src/java/org/apache/commons/logging/LogSource.java,v 1.12 2002/02/03 01:31:54 sanders Exp $
- * $Revision: 1.12 $
- * $Date: 2002/02/03 01:31:54 $
+ * $Header: /home/jerenkrantz/tmp/commons/commons-convert/cvs/home/cvs/jakarta-commons//logging/src/java/org/apache/commons/logging/LogSource.java,v 1.13 2002/02/14 00:19:03 craigmcc Exp $
+ * $Revision: 1.13 $
+ * $Date: 2002/02/14 00:19:03 $
  *
  * ====================================================================
  *
@@ -93,8 +93,11 @@ import org.apache.commons.logging.impl.NoOpLog;
  * <li>At runtime, call <code>LogSource.setLogImplementation()</code>.</li>
  * </ul>
  *
+ * @deprecated Use {@link LogFactory} instead - The default factory
+ *  implementation performs exactly the same algorithm as this class did
+ *
  * @author Rod Waldhoff
- * @version $Id: LogSource.java,v 1.12 2002/02/03 01:31:54 sanders Exp $
+ * @version $Id: LogSource.java,v 1.13 2002/02/14 00:19:03 craigmcc Exp $
  */
 public class LogSource {