slf4j-lambda's Introduction

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);

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