A set of utility methods that can be used in Kotlin or Java.

• Main reason why I use this, is to provide info on what class instance was used.
• Quite commonly I attach it to the caller itself, to figure out who executed the function. As this is quite standardised, it is quite easy to filter out the results.
• This also works very well, when mutliple objects generate same message, as this class prints out the hex for the object. So it is visible, that the object is different for each message.

When it comes to backtracing your app / service, it is all about the logs and their verbosity. Project maintenance hangs on it.

Usage samples.

• Ex. 1. Appending instance to message with instance where it is used.

  logger.info("onInit(app: $app)".withLogInstance(this))
  

Source

/**
 * Debugging utils
 */
object LogUtils {

    /**
     * Converts [obj] to instance signature
     * Easier to figure out different object instance usage in combination to logging
     */
    @JvmStatic
    fun asStringInstance(obj: Any?): String {
        return if (obj != null) {
            String.format(
                "[%s@%s]",
                obj.javaClass.simpleName,
                Integer.toHexString(obj.hashCode())
            )
        } else "[null@instance]"
    }

    @JvmStatic
    fun asStringInstance(klass: KClass<*>, obj: Any?): String {
        return if (obj != null) {
            String.format(
                "[%s@%s]",
                klass.simpleName,
                Integer.toHexString(obj.hashCode())
            )
        } else "[null@instance]"
    }

    @JvmStatic
    private fun objMessage(klass: KClass<*>, obj: Any?, message: String): String {
        return String.format("%s: %s", asStringInstance(klass, obj), message)
    }

    @JvmStatic
    private fun objMessage(obj: Any?, message: String): String {
        return String.format("%s: %s", asStringInstance(obj), message)
    }

    fun String.withLogInstance(obj: Any?): String {
        return objMessage(obj, this)
    }

    fun String.withKLogInstance(klass: KClass<*>, obj: Any?): String {
        return objMessage(klass, obj, this)
    }

    fun String.withLogClass(klass: Class<*>): String {
        return String.format("[%s]: %s", klass.simpleName, this)
    }

    fun String.withLogKlass(klass: KClass<*>): String {
        return String.format("[%s]: %s", klass.simpleName, this)
    }
}