Trait cqrs_es2::DomainEvent

pub trait DomainEvent: Serialize + DeserializeOwned + Clone + PartialEq + Debug + Sync + Send { }

A DomainEvent represents any business change in the state of an Aggregate. DomainEvents are immutable and with event sourcing they are the source of truth.

The name of a DomainEvent should always be in the past tense, e.g.,

• AdminPrivilegesGranted
• EmailAddressChanged
• DependencyAdded

To simplify serialization, an event should be an enum, and each element should have a payload. By convention, the payload has the same name as the element, and elements that do not require additional information use an empty payload.

Though the DomainEvent trait only has a single function, the events must also derive a number of standard traits.

• Clone - events may be cloned throughout the framework, particularly when applied to queries
• Serialize and Deserialize - required for persistence
• PartialEq and Debug - needed for effective testing

Examples

#[derive(
    Clone,
    Debug,
    Serialize,
    Deserialize,
    PartialEq
)]
pub enum CustomerEvent {
    NameChanged(NameChanged),
    EmailUpdated(EmailUpdated),
}

#[derive(
    Clone,
    Debug,
    Serialize,
    Deserialize,
    PartialEq
)]
pub struct NameChanged {
    changed_name: String,
}

#[derive(
    Clone,
    Debug,
    Serialize,
    Deserialize,
    PartialEq
)]
pub struct EmailUpdated {
    new_email: String,
}

Implementors