Logging with SLF4J

From JQuantLib

Contents 1 Introduction 2 Usage 2.1 Get a logger 2.2 Use the logger

Introduction

In JQuantlib we use the SLF4J logging framework (an abstraction layer for the concrete logging implementation).

Usage

Get a logger

As usual get a static Logger from the LoggerFactory

final static Logger logger = LoggerFactory.getLogger(ThisClass.class);

Note: Using a static logger has three main consequences:

• It is faster (compared to non-static)
• You don't have to care about potential serialization issues
• BUT: YOU MAY GET SEVERE CLASSLOADER PROBLEMS (eg. in JEE servers)

Use the logger

Using SLF4J you don't have to guard your logging statements any longer. To avoid the evaluation of expressions, when logging is disabled (on the respective level) you have to use parameterized logging. I.e.

logger.debug("The entry is {}.", entry);

the {} will be substituted by entry if logging on the respective level is in fact enabled. The substitution mechanism works for up to two objects (when more substitutions are required, you can use an array, check the apidoc ).