Struct Mediator

Source

pub struct Mediator { /* private fields */ }

Expand description

In-process dispatcher for commands, queries and notifications.

Construct one with MediatorBuilder, clone it freely (the registry is shared behind an Arc), and call Mediator::send, Mediator::query or Mediator::publish from anywhere in your async runtime.

Implementations§

Source §

impl Mediator

Source

pub async fn send<C: Command>( &self, command: C, ) -> Result<C::Output, HexeractError>

Dispatches a Command to its registered handler and returns the handler’s output.

A fresh CorrelationId is minted for this dispatch. To continue an existing causal chain (e.g. from inside another handler), use Mediator::send_with_correlation_id instead.

§Errors

Returns HexeractError::HandlerNotFound if no handler is registered for C, or the handler’s own error converted into HexeractError when the handler itself fails.

Source

pub async fn send_with_correlation_id<C: Command>( &self, command: C, correlation_id: CorrelationId, ) -> Result<C::Output, HexeractError>

Dispatches a Command to its registered handler using the supplied CorrelationId, preserving the causal chain across in-process dispatches.

Use this variant when the caller already holds a CorrelationId (for example ctx.correlation_id inside a handler) and wants all follow-up messages to share the same identifier. The plain Mediator::send method is equivalent to calling this with CorrelationId::new().

§Errors

Returns HexeractError::HandlerNotFound if no handler is registered for C, or the handler’s own error converted into HexeractError when the handler itself fails.

Source

pub async fn query<Q: Query>( &self, query: Q, ) -> Result<Q::Output, HexeractError>

Dispatches a Query to its registered handler and returns the handler’s output.

A fresh CorrelationId is minted for this dispatch. To continue an existing causal chain, use Mediator::query_with_correlation_id instead.

§Errors

Returns HexeractError::HandlerNotFound if no handler is registered for Q, or the handler’s own error converted into HexeractError when the handler itself fails.

Source

pub async fn query_with_correlation_id<Q: Query>( &self, query: Q, correlation_id: CorrelationId, ) -> Result<Q::Output, HexeractError>

Dispatches a Query to its registered handler using the supplied CorrelationId, preserving the causal chain across in-process dispatches.

Use this variant when the caller already holds a CorrelationId (for example ctx.correlation_id inside a handler) and wants all follow-up messages to share the same identifier. The plain Mediator::query method is equivalent to calling this with CorrelationId::new().

§Errors

Returns HexeractError::HandlerNotFound if no handler is registered for Q, or the handler’s own error converted into HexeractError when the handler itself fails.

Source

pub async fn publish<N: Notification>( &self, notification: N, ) -> Result<(), HexeractError>

Publishes a Notification to every handler registered for N. A notification with zero handlers is a no-op.

A fresh CorrelationId is minted for this dispatch. To continue an existing causal chain, use Mediator::publish_with_correlation_id instead.

Handlers are dispatched concurrently: every handler future is built up front and driven together with join_all, so a slow handler no longer blocks the handlers registered after it. The fan-out is cooperative and runtime-agnostic: it runs on the caller’s task without spawning, so a CPU-bound handler that never .awaits still blocks its siblings until it yields. Every handler shares the same CorrelationId so traces can link the fan-out to its source publish call, but each handler receives a dedicated MessageId.

§Ordering

Execution is interleaved, so the order in which handlers observe the notification is unspecified. Only the collection order is deterministic: the NotificationFailures aggregated on failure appear in handler registration order.

§Errors

Every handler runs regardless of its siblings. If one or more fail, their typed errors are aggregated into HexeractError::PublishFailed, each NotificationFailure retaining the failing handler’s name and the error source chain so the caller can recover an individual failure instead of parsing a flattened string.

Source

pub async fn publish_with_correlation_id<N: Notification>( &self, notification: N, correlation_id: CorrelationId, ) -> Result<(), HexeractError>

Publishes a Notification to every handler registered for N using the supplied CorrelationId, preserving the causal chain across in-process dispatches.

Use this variant when the caller already holds a CorrelationId (for example ctx.correlation_id inside a handler) and wants all follow-up messages to share the same identifier. Every handler in the fan-out receives the same supplied id and a dedicated MessageId. The plain Mediator::publish method is equivalent to calling this with CorrelationId::new().