CODEWITHSUNDEEP
kotlinannotations
bpereira
bpereira

Reputation: 1016

Implement @slf4j annotation from Lombok in Kotlin

Is there a way to implement something similar to Lombok's annotation @slf4j with annotation class in Kotlin?

Right now I have an extension function that instantiates a Logger Factory for me, and I must create these variables in each of my classes just like the example below:

@RestController
@RequestMapping("/api/v1/sample")
class SampleController() {
    private val log = logger()

    @GetMapping
    fun show(): String {
        log.info("SOME LOGGING MESSAGE")
        return "OK"
    }
}

inline fun <reified T> T.logger(): Logger {
    if (T::class.isCompanion) {
        return LoggerFactory.getLogger(T::class.java.enclosingClass)
    }
    return LoggerFactory.getLogger(T::class.java)
}

What I want to achieve is something like:

@Logger
@RestController
@RequestMapping("/api/v1/sample")
class SampleController() {
    @GetMapping
    fun show(): String {
        log.info("SOME LOGGING MESSAGE")
        return "OK"
    }
}

Upvotes: 8

Views: 8041

Answers (2)

NeilenMarais
NeilenMarais

Reputation: 3109

Turning Danny Lagrouw's comment into an answer:

You can get a similar to @Slf4j low-boilerplate solution that does not require you to specify the class manually by using Micro Utils' kotlin-logging

import mu.KotlinLogging

private val log = KotlinLogging.logger {}

class LoggingDemoClass() {

  fun logSometing() {
    log.info("Logging like a pro!")
  }
}

Caveat: I've only just started using it but and haven't investigated any of the kotlin sugar it puts on top of Slf4j but so far it seems to handle well enough as a drop-in replacement for @Slf4j in kotlin code.

Upvotes: 1

Amund
Amund

Reputation: 81

made this pretty thing yesterday

@Target(AnnotationTarget.CLASS)
@Retention(AnnotationRetention.RUNTIME)
annotation class Log {
    companion object {
        inline var <reified T> T.log: Logger
            get() = LoggerFactory.getLogger(T::class.java)
            set(value) {}
    }
}
edit:

Don't use this mess above. use

companion object {
    private val log: Logger = LoggerFactory.getLogger(this::class.java)
}

see Idiomatic way of logging in Kotlin

Upvotes: 7

Related Questions