1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
//! `AsyncSubject` example
//!
//! This example demonstrates the usage of the `AsyncSubject` in the `rxr` library.
//!
//! The `AsyncSubject` is a type of subject in reactive programming that emits only
//! the last value emitted by the source observable, only after that observable
//! completes. If the source observable terminates with an error, the `AsyncSubject`
//! will propagate that error.
//!
//! To run this example, execute `cargo run --example async_subject`.
use std::fmt::Display;
use rxr::{subjects::AsyncSubject, subscribe::Subscriber};
use rxr::{ObservableExt, Observer, Subscribeable};
pub fn create_subscriber<T: Display>(subscriber_id: i32) -> Subscriber<T> {
Subscriber::new(
move |v| println!("Subscriber #{} emitted: {}", subscriber_id, v),
|_| eprintln!("Error"),
move || println!("Completed {}", subscriber_id),
)
}
pub fn main() {
// Initialize a `AsyncSubject` and obtain its emitter and receiver.
let (mut emitter, mut receiver) = AsyncSubject::emitter_receiver();
// Registers `Subscriber` 1.
receiver.subscribe(create_subscriber(1));
emitter.next(101); // Stores 101 ast the latest value.
emitter.next(102); // Latest value is now 102.
// All Observable operators can be applied to the receiver.
// Registers mapped `Subscriber` 2.
receiver
.clone() // Shallow clone: clones only the pointer to the `AsyncSubject` object.
.map(|v| format!("mapped {}", v))
.subscribe(create_subscriber(2));
// Registers `Subscriber` 3.
receiver.subscribe(create_subscriber(3));
emitter.next(103); // Latest value is now 103.
// Emits latest value (103) to registered `Subscriber`'s 1, 2 and 3 and calls
// `complete` on each of them.
emitter.complete();
// Subscriber 4: post-completion subscribe, emits latest value (103) and completes.
receiver.subscribe(create_subscriber(4));
// Called post-completion, does not emit.
emitter.next(104);
}