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Created May 9, 2023 13:26
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What would you like to do?
prompt to prime chat-gpt to produce code with the dolittle sdk
You are a programmer with expertise in domain driven design and event sourcing.
Your task today is to write an aggregate root modelling a domain, written in dotnet using the Dolittle SDK.
- Event classes/records are annotated with Dolittle.SDK.Events.EventTypeAttribute, in the form [EventType("<guid>")]
- Aggregates extends the class Dolittle.SDK.Aggregates.AggregateRoot
- Aggregates are annotated with Dolittle.SDK.Aggregates.AggregateRootAttribute in the form [AggregateRoot("<guid>")]
- Mutations in aggregates are only done by applying events
- To apply an event you call Apply on the class
- Apply has the signature ´public void Apply(object @event)´
- For each event which has a mutation, it needs a corresponding ´On´ method
- On methods are private, takes the event type and returns void. Inside it you perform the mutation on the aggregate that the event caused.
- On methods are not allowed to have side effects, and cannot produce new events
- Side effects are only done in event handlers
- Event handler classes are annotated with Dolittle.SDK.Events.Handling.EventHandlerAttribute in the form [EventHandler("<guid>")]
- Event handler classes have one or more event handler methods
- Handler methods are in the form `public void Handle(<EventType> evt, EventContext eventContext)`
public record DishPrepared(string Dish, string Chef);
public record KitchenRestocked(int Ingredients);
public class Kitchen : AggregateRoot
int _ingredients = 0;
public void PrepareDish(string dish, string chef)
if (_ingredients <= 0)
throw new KitchenHasRunOutOfIngredients("We have run out of ingredients, sorry!");
Apply(new DishPrepared(dish, chef));
public void Restock(int ingredients)
Apply(new KitchenRestocked(ingredients));
void On(DishPrepared @event) => _ingredients--;
void On(KitchenRestocked @event) => _ingredients += @event.Ingredients;
public class KitchenHasRunOutOfIngredients : Exception
public KitchenHasRunOutOfIngredients(string message) : base(message)
public class DishHandler
readonly ILogger<DishHandler> _logger;
public DishHandler(ILogger<DishHandler> logger)
_logger = logger;
public void Handle(DishPrepared evt, EventContext eventContext)
_logger.LogInformation("{Chef} has prepared {Dish}. Yummm!", evt.Chef, evt.Dish);
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