러스트로 작성된 퍼사드

퍼사드는 구조 디자인 패턴이며 간단한 (그러나 제한된 인터페이스를 클래스, 라이브러리 또는 프레임워크로 구성된 복잡한 시스템에 제공합니다.

퍼사드는 앱의 전반적인 복잡성을 줄이는 동시에 원치 않는 의존성들을 한 곳으로 옮기는 것을 돕습니다.

Conceptual Example

pub struct WalletFacade hides a complex logic behind its API. A single method add_money_to_wallet interacts with the account, code, wallet, notification and ledger behind the scenes.

wallet_facade.rs

use crate::{
    account::Account, ledger::Ledger, notification::Notification, security_code::SecurityCode,
    wallet::Wallet,
};

/// Facade hides a complex logic behind the API.
pub struct WalletFacade {
    account: Account,
    wallet: Wallet,
    code: SecurityCode,
    notification: Notification,
    ledger: Ledger,
}

impl WalletFacade {
    pub fn new(account_id: String, code: u32) -> Self {
        println!("Starting create account");

        let this = Self {
            account: Account::new(account_id),
            wallet: Wallet::new(),
            code: SecurityCode::new(code),
            notification: Notification,
            ledger: Ledger,
        };

        println!("Account created");
        this
    }

    pub fn add_money_to_wallet(
        &mut self,
        account_id: &String,
        security_code: u32,
        amount: u32,
    ) -> Result<(), String> {
        println!("Starting add money to wallet");
        self.account.check(account_id)?;
        self.code.check(security_code)?;
        self.wallet.credit_balance(amount);
        self.notification.send_wallet_credit_notification();
        self.ledger.make_entry(account_id, "credit".into(), amount);
        Ok(())
    }

    pub fn deduct_money_from_wallet(
        &mut self,
        account_id: &String,
        security_code: u32,
        amount: u32,
    ) -> Result<(), String> {
        println!("Starting debit money from wallet");
        self.account.check(account_id)?;
        self.code.check(security_code)?;
        self.wallet.debit_balance(amount);
        self.notification.send_wallet_debit_notification();
        self.ledger.make_entry(account_id, "debit".into(), amount);
        Ok(())
    }
}

wallet.rs

pub struct Wallet {
    balance: u32,
}

impl Wallet {
    pub fn new() -> Self {
        Self { balance: 0 }
    }

    pub fn credit_balance(&mut self, amount: u32) {
        self.balance += amount;
    }

    pub fn debit_balance(&mut self, amount: u32) {
        self.balance
            .checked_sub(amount)
            .expect("Balance is not sufficient");
    }
}

account.rs

pub struct Account {
    name: String,
}

impl Account {
    pub fn new(name: String) -> Self {
        Self { name }
    }

    pub fn check(&self, name: &String) -> Result<(), String> {
        if &self.name != name {
            return Err("Account name is incorrect".into());
        }

        println!("Account verified");
        Ok(())
    }
}

ledger.rs

pub struct Ledger;

impl Ledger {
    pub fn make_entry(&mut self, account_id: &String, txn_type: String, amount: u32) {
        println!(
            "Make ledger entry for accountId {} with transaction type {} for amount {}",
            account_id, txn_type, amount
        );
    }
}

notification.rs

pub struct Notification;

impl Notification {
    pub fn send_wallet_credit_notification(&self) {
        println!("Sending wallet credit notification");
    }

    pub fn send_wallet_debit_notification(&self) {
        println!("Sending wallet debit notification");
    }
}

security_code.rs

pub struct SecurityCode {
    code: u32,
}

impl SecurityCode {
    pub fn new(code: u32) -> Self {
        Self { code }
    }

    pub fn check(&self, code: u32) -> Result<(), String> {
        if self.code != code {
            return Err("Security code is incorrect".into());
        }

        println!("Security code verified");
        Ok(())
    }
}

main.rs

mod account;
mod ledger;
mod notification;
mod security_code;
mod wallet;
mod wallet_facade;

use wallet_facade::WalletFacade;

fn main() -> Result<(), String> {
    let mut wallet = WalletFacade::new("abc".into(), 1234);
    println!();

    // Wallet Facade interacts with the account, code, wallet, notification and
    // ledger behind the scenes.
    wallet.add_money_to_wallet(&"abc".into(), 1234, 10)?;
    println!();

    wallet.deduct_money_from_wallet(&"abc".into(), 1234, 5)
}

Output

Starting create account
Account created

Starting add money to wallet
Account verified
Security code verified
Sending wallet credit notification
Make ledger entry for accountId abc with transaction type credit for amount 10

Starting debit money from wallet
Account verified
Security code verified
Sending wallet debit notification
Make ledger entry for accountId abc with transaction type debit for amount 5