Rust 适配器模式讲解和代码示例
适配器是一种结构型设计模式， 它能使不兼容的对象能够相互合作。
适配器可担任两个对象间的封装器， 它会接收对于一个对象的调用， 并将其转换为另一个对象可识别的格式和接口。
Adapter in Rust
In this example, the trait SpecificTarget is incompatible with a call function which accepts trait Target only.
fn call(target: impl Target); The adapter helps to pass the incompatible interface to the call function.
let target = TargetAdapter::new(specific_target); call(target); adapter.rs
use crate::{adaptee::SpecificTarget, Target}; /// Converts adaptee's specific interface to a compatible `Target` output. pub struct TargetAdapter { adaptee: SpecificTarget, } impl TargetAdapter { pub fn new(adaptee: SpecificTarget) -> Self { Self { adaptee } } } impl Target for TargetAdapter { fn request(&self) -> String { // Here's the "adaptation" of a specific output to a compatible output. self.adaptee.specific_request().chars().rev().collect() } } adaptee.rs
pub struct SpecificTarget; impl SpecificTarget { pub fn specific_request(&self) -> String { ".tseuqer cificepS".into() } } target.rs
pub trait Target { fn request(&self) -> String; } pub struct OrdinaryTarget; impl Target for OrdinaryTarget { fn request(&self) -> String { "Ordinary request.".into() } } main.rs
mod adaptee; mod adapter; mod target; use adaptee::SpecificTarget; use adapter::TargetAdapter; use target::{OrdinaryTarget, Target}; /// Calls any object of a `Target` trait. /// /// To understand the Adapter pattern better, imagine that this is /// a client code, which can operate over a specific interface only /// (`Target` trait only). It means that an incompatible interface cannot be /// passed here without an adapter. fn call(target: impl Target) { println!("'{}'", target.request()); } fn main() { let target = OrdinaryTarget; print!("A compatible target can be directly called: "); call(target); let adaptee = SpecificTarget; println!( "Adaptee is incompatible with client: '{}'", adaptee.specific_request() ); let adapter = TargetAdapter::new(adaptee); print!("But with adapter client can call its method: "); call(adapter); } Output
A compatible target can be directly called: 'Ordinary request.' Adaptee is incompatible with client: '.tseuqer cificepS' But with adapter client can call its method: 'Specific request.'
