Trait appliance::Handler

pub trait Handler<M: Message> {
    fn handle(&mut self, msg: M) -> M::Result;
}

A trait which must be implemented for all appliances which are intended to receive messages of type M. One appliance can handle multiple message types.

Handler’s logic is strongly encouraged to include only fast (non-blocking) and synchronous mutations of the appliance state. Otherwise, the appliance’s event loop may get slow, and hence flood the internal buffer causing message sending denials.

Example

type Counter = Appliance<'static, usize>;

struct Ping;

impl Message for Ping { type Result = usize; }

impl Handler<Ping> for Counter {
    fn handle(&mut self, _msg: &Ping) -> usize {
        *self.state() += 1;
        *self.state()
    }
}

struct Reset;

impl Message for Reset { type Result = (); }

impl Handler<Reset> for Counter {
    fn handle(&mut self, _msg: &Reset) {
        *self.state() = 0;
    }
}

const BUF_SIZE: usize = 10;

fn main() -> Result<(), appliance::Error> {
    let descriptor = Appliance::new_bounded(&DEFAULT_EXECUTOR, 0, BUF_SIZE);
    assert_eq!(*descriptor.send_and_wait_sync(Ping)?, 1);
    assert_eq!(*descriptor.send_and_wait_sync(Ping)?, 2);
    descriptor.send(Reset)?;
    assert_eq!(*descriptor.send_and_wait_sync(Ping)?, 1);
    Ok(())
}

Required methods

fn handle(&mut self, msg: M) -> M::Result

Handle the incoming message.

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Implementors

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