桥接模式是指结构设计模式。它允许您通过将逻辑移动到单独的抽象类中来抽象类逻辑的实现。听起来很简单，对吧？
假设我们实现一个垃圾邮件机器人，它应该能够向不同类型的信使发送消息。
我们使用通用协议来实现它：
protocol User {
let token: String
let username: String
}
protocol Messenger {
var authorize(login: String, password: String)
var send(message: String, to user: User)
}
class iSeekUUser: User {
let token: String
let username: String
}
class iSeekU: Messenger {
var authorizedUser: User?
var requestSender: RequestSender?
var requestFactory: RequestFactory?
func authorize(login: String, password: String) {
authorizedUser = requestSender?.perform(requestFactory.loginRequest(login: login, password: password))
}
func send(message: String, to user: User) {
requestSender?.perform(requestFactory.messageRequest(message: message, to: user)
}
}
class SpamBot {
func start(usersList: [User]) {
let iSeekUMessenger = iSeekU()
iSeekUMessenger.authorize(login: "SpamBot", password: "SpamPassword")
for user in usersList {
iSeekUMessennger.send(message: "Hey checkout demensdeum blog! http://demensdeum.com", to: user)
}
}
}
现在让我们想象一下，用于为 iSekU Messenger 发送消息的新的、更快的协议的发布。要添加新协议，您需要复制 iSekU 机器人的实现，仅更改其中的一小部分。如果只改变了一小部分类逻辑，则不清楚为什么要这样做。这种做法违反了 DRY 原则；随着产品的进一步开发，新功能的实现会出现错误和延迟，从而体现出缺乏灵活性。
让我们将协议的逻辑转移到一个抽象类中，从而实现桥接模式：
protocol User {
let token: String
let username: String
}
protocol Messenger {
var authorize(login: String, password: String)
var send(message: String, to user: User)
}
protocol MessagesSender {
func send(message: String, to user: User)
}
class iSeekUUser: User {
let token: String
let username: String
}
class iSeekUFastMessengerSender: MessagesSender {
func send(message: String, to user: User) {
requestSender?.perform(requestFactory.messageRequest(message: message, to: user)
}
}
class iSeekU: Messenger {
var authorizedUser: User?
var requestSender: RequestSender?
var requestFactory: RequestFactory?
var messagesSender: MessengerMessagesSender?
func authorize(login: String, password: String) {
authorizedUser = requestSender?.perform(requestFactory.loginRequest(login: login, password: password))
}
func send(message: String, to user: User) {
messagesSender?.send(message: message, to: user)
}
}
class SpamBot {
var messagesSender: MessagesSender?
func start(usersList: [User]) {
let iSeekUMessenger = iSeekU()
iSeekUMessenger.authorize(login: "SpamBot", password: "SpamPassword")
for user in usersList {
messagesSender.send(message: "Hey checkout demensdeum blog! http://demensdeum.com", to: user)
}
}
}
这种方法的优点之一无疑是能够通过编写实现抽象逻辑的插件/库来扩展应用程序的功能，而无需更改主应用程序的代码。
与策略模式有什么区别？两种模式非常相似，但是，策略描述了切换*算法*，而桥接允许您切换大部分*任何复杂逻辑*。
来源
https://refactoring.guru/ru/design-patterns/bridge
源代码
https://gitlab.com/demensdeum/patterns/ p>
