用Java来说,我试图创建一个对象(严格实例)的集合(向量),每个对象都实现一个接口(特征),因此我可以迭代该集合并对所有对象调用一个方法。
我已将其缩减为下面的一个示例文件,其中包含我希望能够更轻松地获得答案的所有部分。
// main.rs - try and compile using just "rustc main.rs"
use std::io::Result;
/// ////// Part 1
// Types used by implementors of the trait, and in creating a vector of implementors of the trai
pub struct SampleResult {
metric: String,
}
pub trait SampleRunner {
fn run(&self, &'static str) -> Result<SampleResult>;
}
pub struct Sample {
name: &'static str,
runner: &'static SampleRunner,
}
/// /////// Part 2
/// Create one specific static instance of such as Sample
static SAMPLE1: Sample = Sample {
name: "sample",
runner: &Sample1,
};
// need a struct to hold the run method to satisfy the trait???
struct Sample1;
// Implement the trait for this specific struct
impl SampleRunner for Sample1 {
fn run(&self, name: &'static str) -> Result<SampleResult> {
println!("Name: {}", name);
Ok(SampleResult { metric: "OK".to_string() })
}
}
/// /////// Part 3
/// Using the existing static instances of Sample struct, by creating a vector of references for them
/// then iterating over the vector and calling the trait method on each one
fn main() {
let sample_set: Vec<&Sample> = vec![&SAMPLE1];
for sample in sample_set.iter() {
match sample.runner.run(sample.name) {
Ok(result) => println!("Success"),
_ => panic!("failed"),
}
}
}
该特定示例失败并显示以下消息:
error[E0277]: the trait bound `SampleRunner + 'static: std::marker::Sync` is not satisfied in `Sample`
--> <anon>:21:1
|
21 | static SAMPLE1: Sample = Sample {
| _^ starting here...
22 | | name: "sample",
23 | | runner: &Sample1,
24 | | };
| |__^ ...ending here: within `Sample`, the trait `std::marker::Sync` is not implemented for `SampleRunner + 'static`
|
= note: `SampleRunner + 'static` cannot be shared between threads safely
= note: required because it appears within the type `&'static SampleRunner + 'static`
= note: required because it appears within the type `Sample`
= note: shared static variables must have a type that implements `Sync`
但根据我采取的方法,我遇到了许多不同的问题,与Sync
, Sized
等等等等