[Cdk-devel] questions about logger

[M.Le_maudit <mle...@us...>]

Hello everyone.

I have some questions about *how to* and *when* use the logger.


1- Some classes uses the logger and some don't.
   A simple search of the string "import
org.openscience.cdk.tools.LoggingTool;" in all the matching "*.java" files
of the CDK project give this result: The logger is only used in 63 "*.java"
files while the project contains 553 "*.java" files.
So, my questions are:
- When should I use the logger and when should I avoid its use?
- Which arguments must lead me to use the logger?
- Is the logger usage restricted to test classes or not?


2- Sometimes, the logger is declared as a class field and sometimes it is
declared as a local variable within methods.
- When (and why) should I use the logger as a local variable?
- When (and why) should I use the logger as a class's field?


3- When the logger is declared as a class field, the logger is sometimes
declared with the *static* modifier and sometimes not.
- When (and why) should the logger be declared *static*?
- When (and why) should the logger not be declared *static*?


4- When the logger is declared as a class field, the logger is sometimes
declared with a *private* access modifier, and sometimes not.
- When (and why) should the logger be declared *private*?
- When (and why) should the logger not be declared *private*?


5- There are 5 levels which are DEBUG, INFO, WARNING, ERROR and FATAL.
- Which are used and what for? Are there avoided modes?
To be more accurate:
- What sort of messages should be reported with DEBUG mode?
- What sort of messages should be reported with INFO mode?
- What sort of messages should be reported with WARNING mode?
- What sort of messages should be reported with ERROR mode?
- What sort of messages should be reported with FATAL mode?


6- What should be the structure of a log message? Is there a specific format
that you wish to be used? How verbose should be a log message? Humm... I
suppose that this structure is different for each message level. So to be
more precise:
- What is the expected structure of DEBUG messages?
- What is the expected structure of INFO messages?
- What is the expected structure of WARNING messages?
- What is the expected structure of ERROR messages?
- What is the expected structure of FATAL messages?


7- Where should log messages be placed in the source code?



Thanks for yours answers.

Yours.
M.