Spring Boot config loader

ConfigLoader.kt

package com.example.conf

import io.lettuce.core.RedisClient
import io.lettuce.core.RedisURI
import org.slf4j.LoggerFactory
import java.io.FileOutputStream
import java.lang.reflect.UndeclaredThrowableException
import java.nio.ByteBuffer
import java.nio.file.Paths
import java.time.Duration

class ConfigLoadingException(message: String) : Exception(message)
class ConfigLoaderNotFoundException(message: String) : Exception(message)

interface ConfigLoader {
  @Throws(ConfigLoadingException::class)
  fun load(resourceName: String, args: Array<String>)
}

class ConfigLoaderFactory {
  companion object {
    fun loaderOf(type: String): ConfigLoader {
      return when (type) {
        "redis" -> RedisConfigLoader()
        else -> throw ConfigLoaderNotFoundException("Cannot find the config loader typed $type")
      }
    }
  }
}

private class RedisConfigLoader : ConfigLoader {

  override fun load(resourceName: String, args: Array<String>) {
    val logger = LoggerFactory.getLogger(RedisConfigLoader::class.java)

    val classLoader = RedisConfigLoader::class.java.classLoader
    val url = classLoader.getResource(resourceName)
      ?: throw ConfigLoadingException("Cannot find the resource named $resourceName")
    val path = Paths.get(url.toURI())
    logger.info("Resource file path is $path")
    val channel = FileOutputStream(path.toFile()).channel

    val host = args[0]
    val port = args[1].toInt()
    val password = args[2].toCharArray()
    val key = args[3]

    val redisURI = RedisURI(host, port, Duration.ofSeconds(5)).apply { this.password = password }
    val redisClient = RedisClient.create(redisURI)
    val conn = redisClient.connect()
    logger.info("Connected to Redis")

    val value = conn.sync().get(key)
    if (value.isNullOrEmpty()) {
      throw ConfigLoadingException("Cannot read resource from redis with key named $key")
    }
    val buffer = ByteBuffer.wrap(value.toByteArray())
    channel.write(buffer)

    channel.close()
    conn.close()
    redisClient.shutdown()
    logger.info("Replaced the resource file successfully!")
  }
}