EventToolkit

Succinct, dependency-free, ioc-friendly utilities for publishing / subscribing to events within the application domain.

Events

Events aid decoupling and separation of concerns.

public class Fee {
    public RecordPayment(amountPaid) {
      if (amountPaid >= amountOwed)
        EventBus.Publish(new FeePaidOff { Fee = this });
    }
}

[Test]
public void Should_notify_when_the_balance_is_paid_off() {
    Fee paidOffFee = null;
    EventBus.Subscribe<FeePaidOff>(e => paidOffFee = e.Fee);

    var customer = new Customer();
    var fee = customer.ChargeFee(100m);
    fee.RecordPayment(100m);

    paidOffFee.ShouldEqual(fee);
}

Moving non-essential code such as logging into event handlers can isolate your core domain from infrastructure concerns.

public class CustomerMakesPurchaseHandler : Handles<OrderPaid> {
    readonly ILogger logger;

    public CustomerMakesPurchaseHandler(ILogger logger) {
        this.logger = logger;
    }

    protected override void Handle(OrderPaid message) {
        logger.Log(message);
    }
}

Transactions

Events raised within a TransactionScope will be raised once the transaction is completed, or lost if the transaction is cancelled.

    EventBus.Subscribe<FeePaidOff>(e => Console.Log("Fee paid off!"));

    using (var trx = new TransactionScope()) {
        EventBus.Publish<FeePaidOff>(new FeePaidOff { Fee = this });
        Console.Log("Committing transaction...");
        trx.Complete();
    }

    // prints:
    // Comitting transaction...
    // Fee paid off!

Thanks

• Udi Dahan who introduced me to Domain Events
• Jimmy Bogard for a tactical introduction to Domain Events
• sapiens for DomainEventsToolkit, the inspiration for EventToolkit.

Contributing

1. Fork it
2. Create your feature branch (git checkout -b my-new-feature)
3. Commit your changes (git commit -am 'Added some feature')
4. Push to the branch (git push origin my-new-feature)
5. Create new Pull Request