An adapter to use LOG4J as service provider and runtime log engine for the ELF4J (Easy Logging Facade for Java) API
As an application developer using the ELF4J API, I want to have the option of selecting LOG4J as my log engine, at application deploy time without code change or re-compile.
- Java 8+
If you are using the ELF4J API for logging, and wish to select or change to use LOG4J as the run-time implementation, then simply pack this logging service provider in the classpath when the application deploys. No code change needed. At compile time, the client code is unaware of this run-time logging service provider. With the ELF4J facade, opting for LOG4J as the logging implementation is a deployment-time decision.
The usual LOG4J configuration applies.
With Maven, in addition to use compile-scope on the ELF4J API dependency, an end-user application would use runtime-scope for this provider as a dependency:
<dependency>
<groupId>io.github.elf4j</groupId>
<artifactId>elf4j</artifactId>
<scope>compile</scope>
</dependency>
<dependency>
<groupId>io.github.elf4j</groupId>
<artifactId>elf4j-log4j</artifactId>
<scope>runtime</scope>
</dependency>Note: Only one logging provider such as this should be in effect at run-time. If multiple providers end up in the final
build of an application, somehow, then the elf4j.service.provider.fqcn system property will have to be used to select
the desired provider.
java -Delf4j.service.provider.fqcn="elf4j.log4j.Log4jLoggerFactory" -jar MyApplication.jar