Bridge.swift

protocol ClearMessageChannel {
    func send(message:String)
}

protocol SecureMessageChannel {
    func sendEncryptedMessage(encryptedText:String)
}

class Communicator {
    private let clearChannel:ClearMessageChannel
    private let secureChannel:SecureMessageChannel
    
    init(clearChannel:ClearMessageChannel, secureChannel:SecureMessageChannel) {
        self.clearChannel = clearChannel
        self.secureChannel = secureChannel
    }
    
    func sendClearTextMessage(message:String) {
        self.clearChannel.send(message)
    }
    
    func sendSecureMessage(message:String) {
        self.secureChannel.sendEncryptedMessage(message)
    }
}

class LandLine : ClearMessageChannel {
    func send(message: String) {
        print("LandLine: \(message)")
    }
}

class SecureLandLine : SecureMessageChannel {
    func sendEncryptedMessage(encryptedText: String) {
        print("Secure LandLine: \(encryptedText)")
    }
}

class Wireless : ClearMessageChannel {
    func send(message: String) {
        print("Wireless: \(message)")
    }
}

class SecureWireless : SecureMessageChannel {
    func sendEncryptedMessage(encryptedText: String) {
        print("Secure Wireless: \(encryptedText)")
    }
}

var clearChannel = LandLine()
var secureChannel = SecureLandLine()
var comms = Communicator(clearChannel: clearChannel, secureChannel: secureChannel)
comms.sendClearTextMessage("Hello!")
comms.sendSecureMessage("This is a secret")