Struct EventPublisher 

pub struct EventPublisher<E> { /* private fields */ }

A publish-only handle to a bus.

A publisher has no buffer to fill, so a part that only announces holds one rather than a BroadcastBus. Cloning it is cheap, and publishing never waits: a subscriber that falls behind loses events rather than holding up the publisher.

Examples

use pamoja_core::EventBus;
use pamoja_bus::EventPublisher;

let power = EventPublisher::new(8);
let mut control = power.subscribe();
let mut logger = power.subscribe();
assert_eq!(power.publish("battery.low"), 2);
assert_eq!(control.next_event().await?, Some("battery.low"));
assert_eq!(logger.next_event().await?, Some("battery.low"));

Implementations

impl<E: Clone> EventPublisher<E>

pub fn new(capacity: usize) -> Self

Creates a bus with no subscribers yet, and a publisher on it.

Arguments

• capacity - the per-subscriber buffer depth, rounded up to the next power of two. Values below one are raised to one, and values above MAX_CAPACITY are lowered to it.

Returns

A publisher to take subscribers from and publish to them.

pub fn publish(&self, event: E) -> usize

Hands an event to every current subscriber.

Arguments

• event - the event to broadcast.

Returns

How many subscribers the event was handed to. An event published while no one is subscribed is dropped, and the count is 0.

pub fn subscribe(&self) -> BroadcastBus<E>

Subscribes to the bus.

Returns

A handle that receives events published after this call and can also publish.

pub fn publisher(&self) -> EventPublisher<E>

Takes another publisher on the same bus, for another part that announces.

Returns

A publisher with a lifetime of its own, the same as a clone of this one.

Trait Implementations

impl<E: Clone> Clone for EventPublisher<E>

fn clone(&self) -> EventPublisher<E>

Returns a duplicate of the value.

fn clone_from(&mut self, source: &Self)

Performs copy-assignment from source.