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//! Exchange records between workers.
use crate::ExchangeData;
use crate::dataflow::channels::pact::Exchange as ExchangePact;
use crate::dataflow::{Stream, Scope};
use crate::dataflow::operators::generic::operator::Operator;
/// Exchange records between workers.
pub trait Exchange<T, D: ExchangeData> {
/// Exchange records between workers.
///
/// The closure supplied should map a reference to a record to a `u64`,
/// whose value determines to which worker the record will be routed.
///
/// # Examples
/// ```
/// use timely::dataflow::operators::{ToStream, Exchange, Inspect};
///
/// timely::example(|scope| {
/// (0..10).to_stream(scope)
/// .exchange(|x| *x)
/// .inspect(|x| println!("seen: {:?}", x));
/// });
/// ```
fn exchange(&self, route: impl Fn(&D)->u64+'static) -> Self;
}
// impl<T: Timestamp, G: Scope<Timestamp=T>, D: ExchangeData> Exchange<T, D> for Stream<G, D> {
impl<G: Scope, D: ExchangeData> Exchange<G::Timestamp, D> for Stream<G, D> {
fn exchange(&self, route: impl Fn(&D)->u64+'static) -> Stream<G, D> {
let mut vector = Vec::new();
self.unary(ExchangePact::new(route), "Exchange", move |_,_| move |input, output| {
input.for_each(|time, data| {
data.swap(&mut vector);
output.session(&time).give_vec(&mut vector);
});
})
}
}