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Getting Started with EAF Event Sourcing SDK

Quick start guide for implementing event sourcing with the EAF Event Sourcing SDK.

📦 Installation​

Add the dependency to your project:

dependencies {
    implementation("com.axians.eaf:eaf-eventsourcing-sdk:${eafVersion}")
}

⚙️ Configuration​

Configure the event store in your application.yml:

eaf:
  eventsourcing:
    datasource-url: 'jdbc:postgresql://localhost:5432/eventstore'
    username: 'eventstore_user'
    password: '${DATABASE_PASSWORD}'

🚀 Basic Usage​

Define an Aggregate​

@AggregateRoot
class Order : EventSourcedAggregate() {
    private lateinit var orderId: OrderId
    private lateinit var customerId: CustomerId
    private var status: OrderStatus = OrderStatus.DRAFT

    companion object {
        fun create(customerId: CustomerId): Order {
            val order = Order()
            order.apply(OrderCreatedEvent(OrderId.generate(), customerId))
            return order
        }
    }

    fun confirm() {
        require(status == OrderStatus.DRAFT) { "Order already confirmed" }
        apply(OrderConfirmedEvent(orderId))
    }

    override fun applyEvent(event: DomainEvent) {
        when (event) {
            is OrderCreatedEvent -> {
                orderId = event.orderId
                customerId = event.customerId
                status = OrderStatus.DRAFT
            }
            is OrderConfirmedEvent -> {
                status = OrderStatus.CONFIRMED
            }
        }
    }
}

Use the Repository​

@Service
class OrderService(
    private val orderRepository: EventSourcedRepository<Order, OrderId>
) {
    suspend fun confirmOrder(orderId: OrderId) {
        val order = orderRepository.load(orderId)
        order.confirm()
        orderRepository.save(order)
    }
}

Get started with event sourcing using the EAF Event Sourcing SDK.