New kind of logging and exception mapping. WIP

log_ex.kt

package com.expedia.ord.recon

import java.util.*

fun main(args: Array<String>) {
  val helloApp = HelloApp()
  helloApp.work()
  helloApp.funstuff("skiing")
  try {
    val asd = helloApp.otherstuff(10)
    println("otherstuff: $asd")
    val asd2 = helloApp.otherstuff(-1)
    println("otherstuff: $asd2")
  } catch (ex: CustomError) {
    println("Custom error caught: $ex")
  }
}

class HelloApp {
  fun work() = logging {
    println("working...")
    return@logging 1
  }

  fun funstuff(stuff: String) = messageLogging(stuff) {
    println("having fun...")
    1
  }

  fun otherstuff(value: Int) = exceptionMapper(ExceptionMapper()) {
    if (value < 0) {
      throw IllegalArgumentException("otherstuff args")
    } else {
      work()
      value + 10
    }
  }
}

fun <T> exceptionMapper(mapper: ExceptionMapper<T>, method: () -> T): T {
  return try {
    method.invoke()
  } catch (ex: Exception) {
    mapper.map(ex)
  }
}

class ExceptionMapper<T> {
  fun map(ex: Exception): T {
    throw CustomError(ex)
  }
}


class CustomError(ex: Exception) : RuntimeException(ex)

fun <T> messageLogging(stuffName: String, method: () -> T) = logging(
  mapOf(
    "REQUEST_ID" to UUID.randomUUID(),
    "Stuff_Name" to stuffName
  )
  , method
)

fun <T> logging(logMap: Map<String, Any> = emptyMap(), method: () -> T): T {
  if (logMap.isNotEmpty()) println(logMap)
  val result = method.invoke()
  println("End")
  return result
}

Motivation

• Kotlin first
• Spring AOP does not allow same class method calls
• AspectJ is too complicated to setup and problems with kotlin.