org.apache.commons.logging.impl

Concrete implementations of commons-logging wrapper APIs.

Implementation of commons-logging Log interface that delegates all logging calls to the Avalon logging abstraction: the Logger interface.

There are two ways in which this class can be used:

• the instance can be constructed with an Avalon logger (by calling AvalonLogger.AvalonLogger(Logger) ).

Initial configuration of the corresponding Logger instances should be done in the usual manner, as outlined in the Log4J documentation.

The reason this logger is distinct from the 1.3 logger is that in version 1.2 of Log4J:

• class Logger takes Priority parameters not Level parameters.
• class Level extends Priority

Concrete subclass of LogFactory that implements the following algorithm to dynamically select a logging implementation class to instantiate a wrapper for.

• Use a factory configuration attribute named org.apache.commons.logging.Log to identify the requested implementation class.
• Use the org.apache.commons.logging.Log system property to identify the requested implementation class.
• If Log4J is available, return an instance of org.apache.commons.logging.impl.Log4JLogger.
• If JDK 1.4 or later is available, return an instance of org.apache.commons.logging.impl.Jdk14Logger.
• Otherwise, return an instance of org.apache.commons.logging.impl.SimpleLog.

If the selected Log implementation class has a setLogFactory() method that accepts a LogFactory parameter, this method will be called on each newly created instance to identify the associated factory.

Implementation of org.apache.commons.logging.Log that wraps the avalon-logkit logging system.

Trivial implementation of Log that throws away all messages.

In general, the WeakHashtable support added in commons-logging release 1.1 ensures that logging classes do not hold references that prevent an undeployed webapp's memory from being garbage-collected even when multiple copies of commons-logging are deployed via multiple classloaders (a situation that earlier versions had problems with).

Simple implementation of Log that sends all enabled log messages, for all defined loggers, to System.err.

Implementation of Hashtable that uses WeakReference's to hold its keys thus allowing them to be reclaimed by the garbage collector. The associated values are retained using strong references.

This class follows the symantics of Hashtable as closely as possible.