/
App.kt
107 lines (84 loc) · 3.04 KB
/
App.kt
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package ebanx
import java.io.IOException
import java.util.UUID
import org.slf4j.Logger
import org.slf4j.LoggerFactory
fun main() {
val ledger = Ledger()
val provider = PaymentProvider()
val service = PaymentService(ledger, provider)
try {
service.createPayment(PaymentRequest(100))
} catch (e: Exception) {
e.printStackTrace()
}
dump(ledger, provider, service)
}
fun dump(vararg dump: Dump) {
dump.forEach { it.dump() }
}
interface Dump {
fun dump()
}
fun logger(name: String): Logger = LoggerFactory.getLogger(name)
abstract class Service<I, O>(name: String) : Dump {
private val executedRequests = mutableMapOf<I, O>()
private val log = logger(name)
protected fun execute(request: I): O {
log.info("Executing request: {}", request)
val resp = response(request)
executedRequests[request] = resp
log.info("Sending response: {}", resp)
return resp
}
protected abstract fun response(request: I): O
override fun dump() {
log.info("Dumping executed requests")
executedRequests.forEach { log.info("Request {} -> {}", it.key, it.value) }
}
}
enum class ConnectionBehaviour {
FAIL_BEFORE,
FAIL_AFTER,
SUCCEED
}
class Connection<R>(private val behaviour: ConnectionBehaviour, val fn: () -> R) {
fun execute(): R = when (behaviour) {
ConnectionBehaviour.FAIL_BEFORE -> throw IOException("Failed before")
ConnectionBehaviour.FAIL_AFTER -> {
fn()
throw IOException("Failed after")
}
ConnectionBehaviour.SUCCEED -> fn()
}
}
// Ledger
data class DebitRequest(val accountId: Int, val amount: Int)
data class DebitResponse(val transactionId: String)
class Ledger : Service<DebitRequest, DebitResponse>("ledger") {
fun debit(debitRequest: DebitRequest): DebitResponse = execute(debitRequest)
override fun response(request: DebitRequest) = DebitResponse(UUID.randomUUID().toString())
}
// Payment Provider
data class PayRequest(val amount: Int)
data class PayResponse(val transactionId: String)
class PaymentProvider : Service<PayRequest, PayResponse>("paymentProvider") {
fun pay(payRequest: PayRequest): PayResponse = execute(payRequest)
override fun response(request: PayRequest) = PayResponse(UUID.randomUUID().toString())
}
// Payment Service
data class PaymentRequest(val amount: Int)
data class PaymentResponse(val id: String)
class PaymentService(private val ledger: Ledger, private val paymentProvider: PaymentProvider) :
Service<PaymentRequest, PaymentResponse>("paymentService") {
fun createPayment(request: PaymentRequest): PaymentResponse = execute(request)
override fun response(request: PaymentRequest): PaymentResponse {
Connection(ConnectionBehaviour.SUCCEED) {
ledger.debit(DebitRequest(1, request.amount))
}.execute()
Connection(ConnectionBehaviour.SUCCEED) {
paymentProvider.pay(PayRequest(request.amount))
}.execute()
return PaymentResponse(UUID.randomUUID().toString())
}
}