Implement Custom Functionality

Each component must implement the Runnable trait which allows it to be registered with the Engine to ensure that it is run when the simulation starts.

The async run(&self) method is defined by all components that provide custom functionality.

Currently this relies on the #[async_trait(?Send)] support for async traits. The (?Send) decoration indicating that only single-threaded support is required.

use async_trait::async_trait;
use std::marker::PhantomData;
use gwr_engine::traits::{Runnable, SimObject};
use gwr_engine::types::SimResult;

struct MyComponent<T>
where
   T: SimObject
{
   phantom: PhantomData<T>
}
#[async_trait(?Send)]
impl<T> Runnable for MyComponent<T> where T: SimObject {
    async fn run(&self) -> SimResult {
        // Implement custom-functionality

        // Return result - Ok unless there is an error to raise
        Ok(())
    }
}
fn main() {}

The examples/flaky-with-delay gives an example of a component that uses custom run() functionality.

Default Functionality

If the new component does not need to have any custom behaviour and is simply connecting a collection of sub-components then it can implement just use the default Runnable provided by the library with a derive statement.

use async_trait::async_trait;
use std::marker::PhantomData;
use gwr_engine::traits::SimObject;
use gwr_model_builder::Runnable;
use gwr_engine::types::SimResult;

#[derive(Runnable)]
struct MyComponent<T>
where
   T: SimObject
{
    // Component members
   phantom: PhantomData<T>
}
fn main() {}