skeletal-kmemimg.kt

// Skeletal Kotlin TL;DR for the truly impatient:
class MemoryImageProcessor(private val system: Any, 
                           private val eventSourcing: EventSourcing) {
    init {
        synchronized(this) {
            eventSourcing.replay<Command> { command -> command.applyTo(system) }
        }
    }

    fun execute(command: Command): Unit = synchronized(this) {
        TxManager.begin()
        try {
            command.applyTo(system)
            eventSourcing.append(command)
        } catch (e: Exception) {
            TxManager.rollback()
            throw e
        }
    }

    fun execute(query: Query): Any? = query.extractFrom(system)
}