Slf4j-Lambda

Slf4j logging with Java 8 lambda expressions.

The lambda expressions are evaluated only when the log level is enabled.

Requirements

• Java 8
• Slf4j API

Dependencies

dependencies {
    implementation 'kr.pe.kwonnam.slf4j-lambda:slf4j-lambda-core:0.1'
}

Usages

• Use LambdaLoggerFactory instread of Slf4j's LoggerFactory
• Use LambdaLogger instead of Slf4j's Logger. LambdaLogger inherits Logger, so you can still use all Logger's logging methods with lambda supporting logging methods.

import kr.pe.kwonnam.slf4jlambda.LambdaLogger;
import kr.pe.kwonnam.slf4jlambda.LambdaLoggerFactory;

LambdaLogger log = LambdaLoggerFactory.getLogger(YourClass.class);

// lambda for message itself
log.debug(() -> createMessage("debug level"));

// lambda for message format's arguments
log.info("info lambda formatter number {}, string {}", () -> 123, () -> "Hello LambdaLogger");

// method reference
public String longRunnigMethod() {
    return "some long running method";
}

log.debug("Long running method logging {}", this::longRunnigMethod);

// exception logging
log.error(() -> "error lambda exception msg - " + ex.getMessage(), ex);