Package js.log

Logging system.

See: Description

Interface Summary

Interface	Description
Log	A log instance has a name and supplies means to write log messages with priority level.
LogContext	Logger context stores diagnostic context data to current thread.
LogProvider	Log service provider interface.

Class Summary

Class	Description
AbstractLog	Basic implementation of logger interface.
DefaultLog	Default logger used when logger implementation is missing.
DefaultLogContext	Default log context does nothing.
DefaultLogProvider	Default log provider creates DefaultLog instances.
LogFactory	Logging system facade.

Enum Summary

Enum	Description
LogLevel	Logging level, also known as priority.

Package js.log Description

Logging system. This package contains both service providers interface and client API. At a minimum service provider should implement LogProvider and AbstractLog.

Client usage is classic: uses LogFactory to get named logger instance the operates on it.

 public class Sample {
        private static final Log log = LogFactory.getLog(Sample.class);
        ...
        public void method() {
                log.trace("method()");
                ...
        }
 }
 

Formatted Log

Is not uncommon to need adding variables to log records and often it is solved using string concatenation. The problem with string concatenation is it is performed even if log level is disabled. Solution to this problem is to wrap into log level enabled check resulting in more verbose code.

        if(log.isEnabledFor(Level.DEBUG)) {
                log.debug("Class loaded " + class.getName());
        }
 

instead of

        log.debug("Class loaded %s.", class.getName());
 

The second solution executes string formatting only if log level is enabled but check for level is performed into logger writer.

Version:

final

Author:

Iulian Rotaru