h1. Tuscany/TuscanyJava/DAS Java Overview/Improved logging


h3. Logging Overview

*Overview*
* Tuscany DAS uses log4J as its logging mechanism. For more information and complete documentation on log4j, please visit their website ([http://logging.apache.org/log4j/docs/])

*Using log while contributting for Tuscany DAS code*
* While contributing to DAS code, please follow the following guidelines to add logging to your class
\\
_Instantiate a logger_\\
\- There is a logger factory available in org.apache.tuscany.das.rdb.util - To use it
** private final Logger logger = LoggerFactory.INSTANCE.getLogger(MappingWrapper.class);

\- To instrument your code with logging capabilities
** if(this.logger.isDebugEnabled())
*** this.logger.debug("your debug message");

Note: As a performance enhancement, please surround your debug code with a check to see if debug is enabled or not.

*Configuring DAS logging (log4j)*
* _Configuring with Tomcat_\\
There are two ways to configure log4j in Tomcat :
** \- Having a global log4j.properties inside %CATALINA_HOME%\common\classes
\\
\- Having a global log4j.properties inside your own web app at WEB-INF\classes

*Sample log4j.properties*

\# Set root logger level to DEBUG and its only appender to A1.

log4j.rootLogger=INFO, A1

\# A1 is set to be a ConsoleAppender.

log4j.appender.A1=org.apache.log4j.ConsoleAppender

\# A1 uses PatternLayout.

log4j.appender.A1.layout=org.apache.log4j.PatternLayout log4j.appender.A1.layout.ConversionPattern=\[DAS RDB\] - %c
{1}
.%M (%L) : %m %n
\# Print only messages of level WARN or above in the package com.foo.

log4j.logger.org.apache.tuscany=OFF \*\* For further information, please follow the link : [Tomcat FAQ - Logging|http://tomcat.apache.org/faq/logging.html]